Category Archives: Heart Rate Variability

Articles about HRV and training.

How to increase HRV: Part 2 – Nutrition

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In Part 1 of this series I discussed inflammation and its relationship with HRV. Through monitoring my HRV daily I’ve learned that nutrition plays an important role in improving or reducing your adaptive capacity. Eating foods that promote inflammation in the body creates stress that your body must deal with. In dealing with this stress we reduce our ability to adapt and recover from training. Below is a screen shot of my HRV trend over a week of eating large amounts of foods commonly known to promote inflammation. You can see my scores drop each day and only return once I resumed eating better foods. This experience inspired this article series. To discuss the details of nutrition and inflammation I’ve recruited the help of my friend and PhD candidate Marc Morris.

Hi

My name is Marc Morris and I am a PhD student in Nutrition at the University of Saskatchewan. First, I’d like to thank Andrew for the invitation to participate in the discussion surrounding the use of heart rate variability and strength training. The utility of HRV in strength training is very interesting to me. Being a competitive powerlifter, I am always actively seeking ways to improve my training cycles. Truthfully, I don’t know a great deal about this measurement. What I do understand, however, is the potential that exists in a real-time measurement of the autonomic nervous system. Monitored on a daily basis, HRV may provide a tool from which we can objectively auto-regulate our training.

The goal of a dedicated athlete should be to maximize his or her adaptability to training. This is done in part by minimizing unnecessary stress on the body outside of training. From a nutritional standpoint, what you eat (or don’t) can play a significant role in your recovery and adaptability. This is what drew me to nutrition in the first place. Is it possible to improve my performance and body composition through what I consume? Your lifestyle plays a very big role in your training status and may very well be the difference in the transition from mediocre to elite.

We’ve always been told what you eat can effect performance (I’ve also learned that it’s a good idea to learn why you’ve always been told something on your own terms – usually these beliefs fall into the class of dogma). But, outside of eating complete junk and feeling like garbage, this is a tough concept to see and feel. It may not noticeably affect your body composition, it may not affect your energy, but it may be hindering your recovery. Chronic inflammation is not easy to “feel”. At least not until you’ve over done it.

My job today, and hopefully in future occasions, is to discuss how nutrition may influence inflammation, and what you can do to position yourself to be more adaptable in a training cycle. Andrew noticed a decreasing trend in his HRV over a week of entirely uncharacteristic eating (discussed here). This included plenty of processed foods, trans fats, refined carbohydrates and so on. These foods are common culprits of inflammation in the gut. Andrew felt well rested and rated his overall stress levels as low however his diet that week was creating an apparent stress that he couldn’t feel.

In Part 1, Andrew did a great job distinguishing what we know as acute inflammation, our body’s immediate response to injury and infection, and chronic systemic inflammation. As of late, “inflammation” has been a buzzword in most health circles. It has fallen victim to the black and white, all is bad classification. Chronic inflammation is a lingering, low-grade condition that has been linked to just about every health condition in the modern world, from heart disease to cancer. Managing this type of inflammation will help you not only avoid chronic disease in the latter half of your life, but could improve your performance now.

Health professionals may use biomarkers such as C-Reactive Protein (CRP, an acute inflammatory protein) and interleukin-6 (IL-6, a cytokine involved in the inflammatory response) to assess chronic inflammation (despite having a half life of 19-hours, CRP seems to correspond to the chronic condition pretty well). This may be suitable for someone that regularly visits the doctor. But, if you’re a healthy individual these tests will be costly and invasive (blood drawn). Additionally, this type of test won’t allow for an ideal frequency.

The most pronounced effect of diet on inflammation involves the essential fatty acids (EFA). Without going into too much of the physiology about this, the omega-3 and omega-6 fatty acids act as substrates in cascades that control inflammatory products (De Caterina and Basta, 2001 [free review]). Neither are bad, per se, however, the typical North American diet contains larger amounts of omega-6 that largely affect the pro-inflammatory pathway. This topic is so vast it deserves an entire blog post itself. The take home message would be: increase omega-3 intake to balance fats by eating fatty fish (or at least supplement with fish oil).

The ingestion of trans-fats have been shown to increase inflammatory markers, such as the aforementioned markers, CRP and IL-6 (Baer et al. 2004). To minimize low-grade chronic inflammation this would be a fatty acid to avoid (Calder et al. 2011). Foods such as pastries, doughnuts, margarine, and other snack foods commonly have high amounts of this unhealthy fat. So, apart from minimizing excess calorie intake, the high trans fat content of “junk” foods and its effect on inflammation is another reason to avoid these.

The last dietary factor I would like to address today would be alcohol. In small doses (1-2 drinks/day), alcohol has consistently shown to have an anti-inflammatory effect. Above this moderate dose, this effect changes to pro-inflammatory. So a glass of red wine every once in a while isn’t such a bad thing. However, going out and having 10 drinks will have some unwanted effects on your recovery (inflammation being only one of many negative effects).

It is important to acknowledge that not everyone is the same. Dietary choices may have a differing inflammatory response in each person. Having said that, below this article there is a chart of foods that are typically anti-inflammatory verses foods that are typically pro-inflammatory.

That’s it for today. In future posts, I’d like to address the macronutrient composition of the diet and the hypothesized mechanisms for dietary related inflammation.

Note: We are reluctant to categorize foods as in many cases it’s effect on the body is conditional. For example, lactose intolerant individuals will have a more adverse reaction to dairy than one who isn’t lactose intolerant. People with gluten sensitivity should obviously avoid gluten. So take this chart with a grain of salt as they are just intended to be generalizations.

Foods That Promote Inflammation

Foods That Reduce Inflammation
Pastries/Doughnuts Ginger
Margarine Tumeric
Dairy Onions
Gluten Garlic
Refined Wheat Products (breads, pastas) Citurs Peel
Peanuts Olive Oil
Hydrogenated Oils Organic, Grass Fed Meats
Vegetable Oil Wild Caught Fish
Grain/Corn Fed Meat and Fish Green Tea
Processed/Deli Meats Green Veggies (Broccoli, Kale)
Sugar Berries

Practical Applications:

  • Try and stick to grass fed meats and wild caught fish
  • Eat plenty of fruits and vegetables
  • Drink tea
  • Use spices and herbs when cooking
  • Use olive oil
  • Try to minimize refined carbohydrate sources

Note: We understand that eating this way isn’t entirely practical for students and busy folks. The key is simply to eat less of the foods you know may be hurting your progress and eat more of the ones you know will help.

References

De Caterina, R., Basta. G. (2001). European Heart Journal Supplements, 3 (Supplement D), D42–D49

Calder, P.C., Ahluwalia, N., Brouns F. et al. (2011). British Journal of Nutrition, 106, S3, 1-78.

Baer, D.J., Judd. J.T., Clevidence, B.A., et al. (2004). American Journal of Clinical Nutrition, 79, 969–973

How to increase HRV – Part 1: Inflammation

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Over the next several posts I’d like to share my thoughts on ways that you can increase your HRV to improve your health, fitness and responsiveness to training. I will tie in some research with anecdotal experience and encourage you to keep in mind that some of this may be a bit theoretical at times. These thoughts are based on my current knowledge level and experience with HRV as well as discussions I’ve had with other like minded individuals (many of which are much more experienced than I).

I’ve spent a lot of time lately reading about the relationship between inflammation and HRV and therefore this will be the focus of today’s discussion. I highly recommend checking out this article where Dr. Miller presents and summarizes some of the research pertaining to nervous system regulation of inflammation and HRV. I don’t yet fully grasp this relationship as the physiology of inflammation can get pretty technical to say the least, but I would still like to offer some thoughts. Before I get into further detail about anything I’ll go over some preliminaries.

What is inflammation?

Inflammation is the protective or destructive response of body tissues to irritation or injury in attempt to maintain tissue homeostasis. Inflammation may be acute or chronic. The hallmark signs of inflammation are; redness, heat, swelling, pain and is often accompanied by loss of function. Too much inflammation or too little inflammation can be indicative of, or lead to a variety of diseases.

At the most basic level inflammation is a sympathetic response. This isn’t exactly black and white however as I’ve come across some research that shows how the SNS can actually play a small role in reducing inflammation in certain organs under certain conditions (Straub et al, 2006). However, for the purpose of this discussion I’ll generalize the SNS as being predominantly involved in inflammatory responses.

Parasympathetic activity on the other hand, modulates inflammation by inhibiting the secretions of pro-inflammatory cytokines (Mravec, 2011). Inflammation is not just caused from physical stress (training, injury, etc) but can also be brought on by; ingesting certain foods, excessive alcohol intake, smoking and exposure to pollution and certain chemicals. It appears that even psychological stress can cause inflammation (Steptoe et al, 2001).

It should be obvious that inflammation is pretty important to one’s survival. Inflammation is a major part of the healing process. For example, inflammation is necessary for hypertrophy (muscle growth) as it participates in protein breakdown, removal of damaged muscle fibers and production of prostaglandins (Pedersen & Hoffman-Goetz, 2000).

To effectively adapt from a stress (like training) we need to allow our body to go through the process of healing itself. In doing so, we increase our tolerance to the initial stressor. With adequate adaptation to strength training, we increase our strength (this applies to endurance, hypertrophy or any other quality you train to develop). So this explains why making sure we are sufficiently adaptable is important.

The simplest and most effective measure of your adaptability in my opinion is through heart rate variability (HRV) monitoring. In short, HRV tells you when your body can tolerate stress well (such as training) and when it can’t. It does so by providing the user with information about the balance of the autonomic nervous system. It does this by measuring the variability between your heart beats over a given period of time.

Generally speaking,

High HRV = low inflammation, good recovery, good testosterone-cortisol ratio, high tolerance to stress (good adaptability) → A green light for training.

Low HRV = an increase in inflammation (not always), insufficient recovery, reduced testosterone-cortisol ratio, low tolerance to stress (poor adaptability) → Reduction or cessation of training suggested.

It can get a little more complicated than this but for now this explanation will suffice.

Back to inflammation…

So even though I just explained why inflammation is important I’ll switch gears here and say that we are not doing ourselves any favors by contributing to further inflammation via nutritional, environmental and/or psychological factors.

Some of this is out of our control such as pollution and mental stress. It can be difficult to control what’s in the air we breathe or the chemicals we absorb from different surfaces and products. We also can’t control our car breaking down or other mentally frustrating events. However, we can control things like what we ingest (and what we don’t for that matter), how much we sleep, our fitness levels, and so forth. Maximizing these controllable variables can really enhance your adaptability by reducing or preventing unnecessary inflammation and/or promoting parasympathetic activity.

The forthcoming installments to this series will focus on ways that can potentially help raise your HRV (nutrition, aerobic work, restoration, massage, etc.).

The plan right now is for the next post to be about nutrition. I’ve enlisted the help of a friend who’s completing his PhD in Nutrition at the University of Saskatchewan to explain how certain foods contribute to inflammation and why this is something we generally want to avoid. I feel that much of the information presented in the next post will really illustrate WHY you should be more conscious about what you eat. As a former athlete and current trainer of athletes I’ve seen what it’s like to be on either side. Athletes know that they’re supposed to eat certain foods and avoid others. But they usually don’t understand why. They have a hard time understanding how what they ate on the weekend can affect their ability to get stronger or faster. We’ll discuss not just the importance of reaching appropriate macronutrients (protein, carbs, fats), but touch on which sources are likely better than others. We’ll touch upon alcohol intake as well since that’s obviously a major factor in the life of college (and let’s be honest, high school) athletes.

Thanks

How effective is pre-planned training?

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I was about 4 weeks out from Canadian Raw Nationals 2011 (powerlifting). I was on pace to hit personal records in all 3 lifts at a lighter bodyweight. I took a scheduled deload and when I started my last training cycle before the meet, the weights felt like a million pounds. I couldn’t fix whatever the problem was and ended up pulling out of the meet. This was a huge disappointment. I thought to myself that there had to have been a way to prevent this or at least see it coming so I could make adjustments in time to avoid such a disaster. I knew about HRV and considered using it before but held off. It was this meet prep disaster that inspired me to purchase the iThlete to determine how useful it is for strength athletes (see my post here for an explanation of what the iThlete is and how it works). It’s now been 8 months since I’ve been using this device and it has changed my whole outlook on managing the training process.

In this post from a couple of months ago I wrote about my observations with HRV. I also gave a vague explanation of how I was then going to use HRV to guide my training. At this point I’d like to share what I’ve learned from measuring my HRV since then.

  • I have not taken a deload week since late January. Typically I would deload after every 3 week cycle. The purpose of the deload was to allow my joints a break from the heavy loading, allow my CNS to recover from the heavy lifting and allow for optimal recovery so I return at a higher level of strength (supercompensation). I was pretty surprised to see that in nearly 2 months of training I have not felt the need to deload. Instead I have simply chosen to take a deload day only when my HRV score was low. I have squatted heavy every week during this experiment because my HRV was always at baseline or above on Mondays (Squat day). I have had to deload on only 3 occasions. All of these occurred on a Wednesday (Bench Day). I continue to make progress every week and therefore will continue with not taking a planned deload week. On my deload days I simply work up to the heaviest weight I can handle with zero strain or struggle for the same amount of reps I would’ve done anyway.

    For example, on Bench day when I needed to deload I was supposed to work up to 3 sets of 3 with a 4 rep max or RPE of 9. However since my HRV was low and I had to deload I simply worked up to 1 set of 3 with a weight that I felt if I added any more weight too, would cause me to strain. For the assistance and accessory work I simply cut the volume in half. The take home message (atleast so far) is that deloading should occur when your body will not tolerate intense training. HRV provides this information. What’s the point of taking a whole week to deload if your ability to adapt to stress returns to a good level within only a few days?

    I will experiment with planned overreaching in the future where I will purposely train heavy as my HRV declines and follow it up with a planned deload. This is more similar to how athletes are training. My concern with this method is the potential heightened risk of injury from training when HRV is low. See this post for further discussion on HRV and injury.

  • This past week was my spring break. I went to Cincinnati to visit my family. If you know me personally you are aware that I’m pretty strict with my eating. I eat a lot, but I stick to whole foods and avoid processed/junk foods. I also eat fairly low carb. Well, in Cincinnati I allowed myself to eat whatever I wanted all week. I was crushing home-made oatmeal butterscotch cookies, ice cream, nacho’s and guacamole, Cheesecake Factory dinners and desserts, the famous Cincinnati Chilli, pub food, etc. It was a disaster. Apart from the binge eating I felt very well rested, slept well and enjoyed some unseasonably warm weather.

    Cincinnati Chili

    It’s fair to say that the only thing out of the ordinary that would have been stressful to my body was my terrible eating. Well, my HRV declined after the second day and it got worse each day after. It only climbed back up again since I returned and resumed my usual eating habits. You can see in the screen shot below that my HRV steadily decreased the longer I ate poorly and started to climb back up on Saturday (returned to PA on Friday evening). Although we’re all well aware that nutrition plays a vital role in how we recover from training and perform, it was pretty eye opening to see just how important nutrition is. Such a simple way to improve performance and adaptation to training is to just eat well. How much time are we wasting busting our ass in the gym if we go home every day and eat terribly?

  • Lately, whenever my HRV is low I feel weaker. I found it interesting that on many squat workouts in the past 6 or 7 weeks I felt that I was fighting the bar, not finding my groove, etc, yet was still squatting heavy. When my HRV has been low (3 low days on Bench days) the weight would feel much heavier. 315×5 is a walk in the park for me typically. However, on a deload day it was a major grind. I really shouldn’t have gone that heavy on a deload. This leads me to believe that performance will be worse when HRV is low (consistent with research that I discuss here.) Since I’ve been able to squat heavy even when my technique felt shaky when HRV was high, it leads me to believe that performance will likely be better when HRV is high. I’ll be doing some research in the near future on collegiate football players to see if I observe the same thing.

My experience with HRV and the research I’ve read thus far has lead me to believe that pre-planned training for collegiate athletes is not optimal. It is common for strength coaches to program around Christmas holidays, spring break and so on. Keep in mind that holiday’s and breaks are usually planned deloading periods that mark the end of a given cycle/phase and will mark the beginning of a new one upon return. This may work if the athlete’s all lived the exact same lives and had the same genes as one another.

A common example of pre-planned periodization that I found on google images

Allow me to illustrate for you an example of how ineffective this method is not because the theory is incorrect (a debate for another time), but because it fails to account for the behaviour of the athletes. I’m going to provide 4 scenario’s of what many athlete’s on the same team may do over the break that will effect there adaptation to the previous cycle and readiness for the next cycle.

Scenario 1: The athlete heads to Florida for spring break and drinks alcohol every day, all day on the beach, parties all night and eats cheap restaurant food.

Scenario 2: The athlete goes home and although doesn’t drink or party all night, he eats terribly.

Scenario 3: The athlete goes home and rests all week and eats perfectly.

Scenario 4: The athlete goes home and trains at his own gym and therefore doesn’t get much rest.

Many football teams have over 100 players. This creates 100 different scenarios. It’s quite obvious that not every athlete will be prepared for the same training loads. Any strength coach is already aware of this and unfortunately has to do their best with what they’ve got. However, since HRV is sensitive to any stress that our body experiences, we now have a more accurate way to determine who is ready and who is not. This can prevent you from overtraining certain athletes, undertraining other athletes and most importantly reducing the likelihood of injury. If you so desired, you can investigate further into the personal lives of the athletes to determine why they are experiencing so much stress when the training isn’t the cause.

I realize that monitoring the HRV of all your athletes may seem impossible but the new apps that are available make it extremely easy and affordable. The biggest challenge becomes how you will handle providing different workouts on a day to day basis according to everyone’s HRV score. I’ll share my thoughts on potential ways to accommodate this in a future post, but I believe it can be done without too much burden.

Today’s post paints a picture of what my current thought process is based on my experience and the literature. I am really excited to get the research started on the football players. In my next post I will give an update of exactly what I’ll be doing, why, my hypothesis and all that good stuff.

Thanks for reading.

If you’re not assessing (the ANS), you’re guessing

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“If you’re not assessing, you’re guessing” is a phrase often used by strength and conditioning professionals to explain the importance of movement assessment prior to exercise prescription. Prescribing a program that doesn’t consider the athlete’s movement ability (or lack thereof) can end up causing problems.Essentially, you would be guessing that your exercise prescription is helpful when in fact it could be exacerbating a problem. I wholeheartedly agree with this. However this article has nothing to do with movement assessment. This was just my way of illustrating what my next point is.

I am going to apply the same logic we use for why we assess movement (to influence program design) with monitoring the function of the autonomic nervous system (ANS); if you’re not assessing the ANS, you’re guessing.

If you’re unfamiliar with what the ANS is and why it’s important I suggest you read this. In a nutshell the ANS governs “rest and digest” and “fight or flight” responses in the body. This is done without our conscious control. The two components of the ANS are the parasympathetic branch and sympathetic branch. Sympathetic activity is elevated in response to stress be it physical, or mental. Adrenaline is secreted and catabolic activity (the breakdown of structures) ensues. Parasympathetic activity is elevated in the absence of stress and functions to heal and repair the body.

We can monitor our ANS status non-invasively and inexpensively through heart rate variability (HRV). I explain how you can do this here.

HRV as an indicator of autonomic function can tell you a tremendous amount about your athlete’s responsiveness to training. I shared plenty of research in this post that lends support to HRV as an effective tool for; reflecting recovery status, showing better adaptation to training and even predicting performance. In a separate post I shared my thoughts on HRV as a predictor for injury.

Let me summarize what I shared in my initial research review post;

HRV reflects recovery status in elite Olympic weightlifters (Chen et al 2011), national level rowers (Iellamo et al 2004) and untrained athletes (Pichot et al 2002).

Cipryan et al (2007) showed that hockey players performed better when HRV was high while performance was rated lower when HRV was low.

Endurance athletes who improved vo2 max had consistently high HRV while athletes who did not improve vo2 max had low HRV (Hedelin et al 2001).

Endurance athletes who trained using HRV to determine their training loads had a significantly higher maximum running velocity compared to athletes in a pre planned training group (Kiviniemi et al 2007, Kiviniemi et al 2010).

Female athletes who used HRV to guide their training increased their fitness levels to the same level as females in a pre planned training group but the HRV group had fewer high intensity training days (Kiviniemi et al 2010).

(references for the above articles can be found in my original post here.

I’d now like to show some more research that lends support to the usefulness of HRV in monitoring athletes.

Mourot, L (2004) saw decreased HRV in overtrained aerobic athletes. Uusitalo et al (2000) also saw decreased HRV in overtrained female aerobic athletes.

Huovinen et al (2009) measured HRV and testosterone to cortisol (T-C) ratio in army recruits during their first week of basic training. The training was class room based (not physical) and therefore all stress can be considered mental. The authors found that HRV declined in several soldiers, though not all. This demonstrates that, what can be interpreted as stress is highly variable and dependent on the individual. The authors used the terms “high responders” and “low responders” to describe the differences among soldiers. Immediately I thought about the differences among athletes and how their bodies perceive stress. You can’t assume everyone is responding in kind to a training program. What is stressful for one athlete may not be as stressful to another.

All soldiers that showed decreases in HRV also showed lower T-C ratios. In contrast, soldiers with higher HRV had higher T-C ratio’s. Baseline T-C levels were not recorded so we shouldn’t draw any concrete conclusions however it appears that low HRV (increased sympathetic activity with parasympathetic withdrawl) is associated with a reduced T-C ratio.

Hellard et al. (2011) found that in national level swimmers, as HRV dropped (sympathetic predominance) there was an increased risk of illness. The drops in HRV that lead to illness were preceded by a sudden increase in parasympathetic activity the week prior to illness. The authors speculated that the preceding increase in HRV (parasympathetic/vagal activity) was a reflection of the body experiencing the first incubation period and that an increase in vagal activity was a protective response trying to modulate the magnitude of early immune responses to inflammatory stimuli. The subsequent increase in sympathetic activity and decrease in HRV occurs during the symptomatic phase of the illness.

In humans, increased sympathetic activity is generally associated with inflammatory responses while parasympathetic predominance actually inhibits inflammation. At this point in time I will not elaborate on this for the simple fact that I don’t fully understand it. However, we can speculate that if we’re seeing consistently low HRV scores in ourselves or our athletes there is probably an increase in inflammation occurring. Check out Thayer (2009) for more information regarding HRV and inflammation. Simon from iThlete sent me that paper and I’m still processing it.

When dealing with a team or if we train multiple athletes at the same time we need to be aware of how they are adapting and recovering from training. Work by Hautala et al (2001) shows that athletes will recover from exercise at different rates according to fitness levels (obviously). Basically, fit individuals recover faster and show less HRV fluctuation compared to less fit individuals. In a team setting, some individuals who are highly fit may not be getting a sufficient training stimulus while other athletes who are less fit can be overworked.

Kiviniemi et al (2010) found that females take longer to recover from aerobic training than males. This needs to be considered if you are training a mixed gender group.

Buchheit et al (2009) and Manzi et al (2009) both found HRV to be a predictor of aerobic performance.

I’m well aware that the development of athletes has been taking place without the use of HRV monitoring. There are many great coaches and trainers who have their own systems and methods of monitoring recovery in their athletes that work well.

HRV is a tool to use within your own systems. I have thoughts about how I would implement this in a team setting that I will share another time.

To truly autoregulate the training of ourselves or of athletes, we need as much information about present physiologic status as possible. Based on the research and my own personal experience with HRV, this technology takes much of the guesswork out of load/volume manipulation and training prescription. Training hard when HRV is low can be counterproductive and delay recovery. Training hard when HRV is chronically low can lead to illness, injury, overtraining syndrome and suppressed testosterone. Alternatively, increasing load/volume on days when HRV is high can lead to more favourable adaptation. HRV can tell us how stressful the training was for our athletes based on how long it takes HRV to reach baseline in subsequent days. HRV can indicate how much stress your athlete is experiencing outside of training. There are several indications one can take from a simple HRV measurement. Further research will reveal more correlation between HRV and sports performance.

I believe that to train an athlete optimally, we need to be assessing the state of the autonomic nervous system… otherwise we’re guessing.

References:

Buchheit, M. et al (2009) Monitoring endurance running performance using cardiac parasympathetic function. European Journal of Applied Physiology, DOI 10.1007/s00421-009-1317-x

Hellard, P., et al. (2011) Modeling the Association between HR Variability and Illness in Elite Swimmers. Medicine & Science in Sports & Exercise, 43(6): 1063-1070

Huovinen, J. et al. (2009) Relationship between heart rate variability and the serum testosterone-to-cortisol ratio during military service. European Journal of Sports Science, 9(5): 277-284

Kiviniemi, A.M., Hautala A.J., Kinnunen, H., Nissila, J., Virtanen, P., Karjalainen, J., & Tulppo, M.P. (2010) Daily exercise prescription on the basis of HR variability among men and women. Medicine & Science in Sport & Exercise, 42(7): 1355-1363.

Manzi, V. et al (2009) Dose-response relationship of autonomic nervous system responses to individualized training impulse in marathon runners. American Journal of Physiology, 296(6): 1733-40

Mourot, L. et al (2004) Decrease in heart rate variability with overtraining: assessment by the Poincare plot analysis. Clinical Physiology & Functional Imaging, 24(1):10-8.

Thayer, J. (2009) Vagal tone and the inflammatory reflex. Cleveland Clinic Journal of Medicine, 76(2): 523-526

Uusitalo, A.L.T., et al (2000) Heart rate and blood pressure variability during heavy training and overtraining in the female athlete. International Journal of Sports Medicine, 21(1): 45-53 


Can HRV predict injury?

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In my first post on HRV I highlighted what I thought to be HRV’s most promising attributes. I would like to add another to that list;

HRV may be able to tell you when you’re at a higher risk of injury.

After one of many e-mail based discussions I’ve had with Simon Wegerif  (creator of iThlete), he  happened to put this idea in my head. I told him about the study we are trying to run here at Cal U where we will compare HRV guided training vs. pre-planned training in off-season collegiate football players. We are looking to see if one method is better than the other for increasing strength. Simon mentioned that we should consider looking at illness and injury among the players as well. He followed up this suggestion by mentioning some research done by a veterinarian who found a correlation between low HRV scores and increased injury rates among race horses.

I immediately began scouring several databases for any research to show HRV as a predictor for injury potential. My search proved to be futile as nothing of note came up. I was however, able to get my hands on the article on race horses Simon had mentioned.

In a nutshell, Dr. Christine Ross monitored the HRV of 16 competitive race horses, all of which were in training. Of the 16, 13 had HRV readings that were associated with pain, fatigue, illness or injury. It was stated that even though the horses appeared healthy and energetic, they were considered “at risk” based on their HRV. There were no outward signs or symptoms to suggest these horses were currently sick or hurt. Within 3 months, 12 of the 13 at-risk horses got injured or sick requiring veterinary intervention and cessation of race training. (Message me if you would like to see the article)

The results of Dr. Ross’ findings are staggering. Can HRV detect the same issues with humans?

Naturally, I began thinking of all of the injuries I’ve had over the years from football, hockey, lifting, etc.

Since I’d only been measuring my HRV for the past 7 months I focused on injuries since mid-August. I just so happened to have injured myself once during this time period. Through my training log I was able to pinpoint the exact day. It was Oct. 11, 2011. During a set of squats with about 60% of my 1 rep max on the bar, I pulled a muscle in my lower back. This injury kept me from lifting for about a month. I cross referenced that day with my HRV scores. Sure enough, my HRV was extremely low at 66.4 and my heart rate that morning was 83.8 beats per minute. Keep in mind that at this time I was simply taking my HRV score for observational purposes and not using it to guide or manipulate my training. In the image below you can see the large downward deflection in HRV from early October when I hurt my back.

Back Injury in October HRV Score

Typically only conditioning workouts or illness cause my HRV to drop so dramatically as I explained previously in this post. In this instance, I had not performed a conditioning session nor was I sick in any of the days prior to the injury. What caused such a significant drop in HRV? Well, that weekend I was in Ohio for my grandmother’s funeral. My best guess is that the emotional stress in addition to the stress from travelling caused this drop.

I wish I had more than animal research and anecdotal experience to share on this topic. I will keep my eyes peeled for any further evidence on this topic. I’m sure coaches who have been monitoring the HRV of their athletes would be able to provide some better insight on the matter.

If HRV happens to be an accurate indicator of a heightened risk of injury (among many of its other purported attributes), would you be monitoring your HRV? If you are a coach, would you want to know the daily HRV scores of your athletes? If one of your starting football players was showing poor HRV scores on a day where you were going to have them perform tackling drills in practice, would you have him sit out? How would you manipulate strength and conditioning training based on your athletes HRV scores?

I hope to shed some light on this topic with the research we are trying to do here at Cal U. I want to monitor the HRV in both training groups and observe what may happen to an athlete in the pre-planned group who may be having low HRV scores. Though we will be measuring strength, we can still observe if and when athletes get sick or hurt.

I’m happy to report that we recently received a sample HRV device from Polar (the RS800 Watch). Our fingers are crossed that we can work something out to get several more for the study!

Download IMG00944-20120211-1535.jpg (245.5 KB)

Have a good weekend!

My observations with HRV and how I will now use HRV to guide my training

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I’ve been monitoring my HRV for almost 7 months. Throughout this time I did not use HRV to guide my training but rather have just observed how my HRV scores responded to my regular routine. My regular routine consisted of training upper body and lower body twice/week. Monday was Squat, Tuesday was Bench, Thursday was Deadlift, Friday was Incline or Overhead press. I’d follow each main lift up with assistance work.  Today I’ll disclose what I’ve learned from my observations and how I will start to use HRV to vary my training.

Observations:

I’ve noticed that conditioning sessions (intervals on steps) affect my HRV the next morning much more than heavy strength work outs. This is obviously because I had been performing no conditioning work within the last year. However, after performing the conditioning sessions consistently over several weeks (one time per week) I noticed an overall improvement in HRV and I no longer experience massive drops the morning after the conditioning session. This is a prime example of HRV reflecting adaptation to what initially was an immense stress on my body. To give you an example, the morning after my first stair interval workout my morning heart rate after waking was 84 bpm and my HRV was 66. My typical morning heart rate is around 60 bpm (give or take) with HRV averaging almost an 80. If I miss a few weeks of conditioning, the next time I do them again my HRV plummets (I have deconditioned) .

We run 67 steps that look very similar to those above for between 30-50 rounds depending on the day.

I’ve recently began performing 20 minute light aerobic recovery work on off days to see what would happen. I found that when I do these consistently my HRV scores show smaller fluctuation from day to day. No surprise here.

I rarely get sick, but when I do, I see a significant drop in HRV. This winter there was a morning where I woke up (from a terrible night’s sleep) with a head cold, stuffed nose, etc. My morning heart rate was 92 bpm and my HRV was 56. This was my worst ever result. Needless to say I did not train that day. In the past I would often debate in my head if I should train anyway. Actually seeing how much it affects my adaptability to training was very eye opening.

I have not experienced any significant changes in HRV from minor muscular injuries. However, I do notice a decline in HRV after a few days if the injury causes me to stop training. Furthermore, I’ve noticed that HRV stays higher on average when I am consistently exercising over time and am more active throughout the days. When I’m at Cal in the weight room every day moving around and training athletes, my HRV is tpyically higher compared to when I go home for a month over Christmas and sit around too much. Within a few days of inactivity I’ll typically see HRV decline somewhat.

I’ve noticed lower HRV scores during times of travel and sleeping at places other than my own bed. I drove 4 hours from Pittsburgh to my folks place in Cincinnati and slept there for 2 weeks. The first two mornings my HRV was noticeably lower than normal. I found this to be surprising as I didn’t feel that the travel was too stressful, nor did I think that sleeping in a different bed was too stressful. This happens pretty much every time I travel.

I have not experienced a correlation with higher strength levels on days where HRV is above baseline. I’m going to elaborate on this more in a different post as I have a lot of thoughts on HRV and performance prediction as well as more research to share regarding this.

How I plan on using HRV to manipulate my training loads:

– I will change from lifting on Mon-Tues-Thurs-Fri , to adjusting to an every other day format. This is because my HRV scores on Tuesday and Friday are always lower due to Monday and Thursday training sessions. Having a day off between workouts allows for an increase in HRV on all training days which hypothetically allows for better adaptation. We’ll see how it affects my training.

– On days where HRV scores are above 80, I will perform a higher volume of work over 90% of my 1 rep max. The idea here is that since I’m more adaptable to training, I will place a greater stress on my body. For example I’ll perform 3 sets of 3 above 90% whereas I typically would do only 1 work set over 90%.

– If HRV is around baseline (77-80) I will perform a lower volume of work over 90% such as 2 sets of 2.

– Finally, if HRV is below baseline I will avoid working over 80%. I typically deload after every 3 week cycle but will no longer be doing so. I will simply reduce volume and intensity on days where HRV is low. I will deload only if and when I feel I need it based on HRV scores, performance markers (strength) and how my joints feel.

For now, this is the plan. The reps and percentages are not set in stone. The main idea is that I’ll be training with high intensity and volume on high HRV days; high intensity and moderate volume on baseline HRV days; deload on low HRV days. If I set any personal records in the gym on Bench, Squat or Deadlift I’ll know the plan is working. I haven’t hit a PR since Canadian Nationals in 2010. This is partially due to injuries and partially due to dropping 20 lbs of body weight. I’ll stop now with the excuses.

In my next post I’ll give an update on the research we’ll be doing here in the weight room with HRV and football players. I’ll also elaborate on my thoughts on HRV and its ability to predict performance.

Thanks for reading.

HRV Explained Part 3: How to measure HRV

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*Update: For a much more thorough and updated description of how to measure HRV please see this post.

If you’ve been following my discussions you’re probably curious about how one goes about monitoring their HRV. Today I’ll inform you of how I monitor mine as well as a few other options available. I strongly suggest reading Part 1 and 2 of my HRV discussion before reading this if you haven’t already.

If you have $30,000+ lying around then you can buy yourself an Omegawave. This device is used by organizations within the NFL, NCAA, Olympics, Pro Soccer leagues in Europe, etc.

Here is a demonstration of NFL players having their HRV measured on the Omegawave prior to training camp.

Assuming that dropping 30 g’s is unreasonable for you there are some other options.

I personally use an app called the iThlete that is compatible with both ios and android. The iThlete requires a heart rate strap and a small ECG receiver that you plug into the headphone jack.

To measure HRV you simply plug the ECG receiver in, strap on the heart rate monitor and press the start button on the app. You should measure HRV in the morning after you wake up. This will give you the most accurate score since you’ve yet to encounter any stressful events for the day. The app will measure your heart rate for about a minute and provide you with your heart rate score in beats per minute (bpm) and HRV. It provides the HRV score through a calculation based on the time interval between each beat. You do not see the raw data but are just given a score. The higher the score for HRV, the more recovered and rested you are (parasympathetic dominant). Here is a screen shot from my score this morning.

HRV and Heart Rate score this morning

*To give you an idea of my HRV scores anything between 77-80 would be good. Anything above would be exceptional recovery and anything under would indicate insufficient recovery. This morning my resting heart rate was 63bpm and my HRV was 81. This is a great score for me.

Now here is where the app gets really cool. If you select the chart button at the bottom of the screen you see a chart of your HRV trends over time. You can see a chart displaying all HRV scores ever measured, all HRV within the last 3 months, 1 month or week. Here is a picture of mine.

HRV Chart

Upward deflections represent higher scores (increase in parasympathetic activity) and the downward deflections represent lower scores (decrease in parasympathetic activity). Green lines tell you that intense training will be well tolerated, amber lines caution you not to go overboard with your training and red lines tell you to take a recovery day.

The massive red downward deflections you see on the chart all occurred the day after I performed intense conditioning sessions. These were so stressful to my body because I’ve been training for powerlifting for the past few years and have done little conditioning. My body was not adapted to that type of training and clearly reflects this in my HRV scores. The most recent drops in HRV (shown in late December) actually show my adaptive reserves plummet while getting sick with a head cold. The first day I started to feel the cold coming on my heart rate was 78bpm and my HRV dropped to 68! The next day (the worst day of my cold) my morning heart rate was 92 and my HRV was 56! Needless to say I did not train on those days.

The last image I’ll show you from the app is the graph you can view.

This displays all of your HRV scores ever taken. You can scroll down for more scores. Additionally you can e-mail your data to your coach or anyone who may be overseeing your training allowing them to make any necessary adjustments in your training.

Another app exists called the Bioforce HRV App. Bioforce is compatible with ios and Android. This was designed by former NFL strength coach and current MMA strength coach Joel Jamieson. This app functions similar to the iThlete as it is manufactured by the same developer. BioForce differs from ithlete mainly in measurement duration (2.5 minutes vs 55 seconds), preferred position (supine vs. seated or standing).

I’ll also mention that Polar has heart rate monitor watches that can also provide HRV scores. The RS800 watch from polar is a valid instrument for collecting RR intervals and has been used quite a bit in research. However, be prepared to manually export your data from the watch to software that can analyze the data. This is not the most convenient option but will provide very accurate data.

If you’re interested in buying an HRV device I suggest you do your research on each one and find which best suits your needs.

In my next post I will discuss what I’ve learned from monitoring my own HRV for the past 7 months or so. I’ll include details on how I’ve altered my training structure because of it and give examples of how I manipulate my training day to day based on my HRV score. Additionally I’ll discuss non-training related events that have sapped my HRV scores that really taught me about how my body responds to things such as travelling, poor sleep, etc. I’ll include anecdotes about when my HRV scores were exceptionally high and what I think may have influenced them.

Thanks for reading.

HRV Explained Part 2: The Research

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In today’s post I want to provide some research to support my bold claims about the effectiveness of HRV. The following research studies have been summarized to make more reader friendly as to not bore anyone who isn’t too interested in research methods, statistical analyses and so on. I have listed the citations for each study at the end for anyone interested in reading the research themselves. Additionally I have each one as a .pdf so just request a copy and I can send it.

HRV Reflecting Recovery status:

Chen et al (2011) found that HRV drops significantly within 24 hours of recovery from a high intensity strength workout in elite male competitive weightlifters and returns to baseline by 72 hours. Weightlifting performance was recovered exceeding baseline and reaching maximum at 72 hours thus showing a significant correlation between HRV and recovery.

Iellamo et al (2004) studied male rowers from the Italian national team during preparation for the world championships. The researchers found that from 50% to 100% of training load, there was a significant decrease in HRV and increase in sympathetic tone. As training reduced to 50% during the World Championships, HRV returned to base line and a return of autonomic indices to previous levels was seen. They concluded that monitoring of HRV can provide useful information to assess the dynamics of training through a simple non-invasive approach.

Pichot et al (2002) set out to test HRV as a practical and reliable marker of fatigue during training. 6 untrained subjects showed improved HRV during intense training. During overload training an increase in sympathetic activity was seen with a corresponding decrease in HRV. During a recovery week there was a sudden and significant rebound of parasympathetic activity and increase in HRV.

Research demonstrating better adaptation to training when HRV scores are high:

Hedelin et al (2001) found that endurance athletes who improved Vo2 max consistently showed higher HRV scores compared to athletes who showed deterioration in aerobic performance; of which showed lower HRV scores.

Kiviniemi and colleagues (2007) split 26 fit males into an HRV guided training group, a pre-planned training group and a control group. The HRV group was given intense training if HRV was the same as baseline or higher while moderate training or complete rest was given with significant drops in HRV. The pre-planned training group followed a pre-planned program typical of most endurance athletes. The results showed that HRV guided training produced a significantly greater increase in maximum velocity running compared to the pre-planned training group.

Kiviniemi et al (2010) conducted a very similar study to their 2007 work but in this case HRV groups were split in to a female group and a male group. The methodology was the same as the 2007 study where HRV groups performed training based on HRV scores while the pre-planned training group had pre programmed training. The results showed that men in the HRV group had greater maximum velocity than the pre planned group consistent with 2007 results. The HRV female group saw no significant increase in maximum velocity over the pre planned group. What’s interesting is that the HRV female group was able to improve their fitness to the same levels of the pre planned group with a lower weekly training load (fewer high intensity training days).

HRV predicting performance:

Cipryan et al (2007) showed that male hockey players have higher rated performances from their coach when HRV is high and that any drops in HRV correspond with a lower rating of performance. Of the sample players, the one with consistently low HRV was rated the lowest in performance. This demonstrates a strong correlation between HRV score and performance.

Devils Advocate

I should mention some research that shows HRV’s inconclusive ability to monitor training in attempt to be impartial. Bosquet et al (2008) performed a literature review to determine if HRV is effective at monitoring over-reaching. They determined that HRV should be used along with other known indicators and symptoms of overtraining to be meaningful. Additionally, Nigam (2010) concluded that HRV is more accurate than heart rate but not enough research exists to use either as a sole indicator of overtraining.

Edit: For more research on HRV see this post.

My Thoughts

It’s pretty evident that HRV can reflect recovery status. This has been demonstrated in both aerobic and strength athletes several times. This quality alone makes HRV worth monitoring if you are serious about your training. I’d like to see more research showing correlations with HRV and performance. Does having high HRV mean we can perform better on that day? Does low HRV doom us to substandard performance? The study on Hockey players is the only paper I found that would suggest this. I personally am not convinced. More research needs to be conducted on strength athletes in particular as this it is greatly lacking.

Grabbing the bull by the horns

Rather than complain that not enough research exists I thought I’d take matters into my own hands. I have proposed a research study to a researcher here at my university with the support of Bobby (the head strength coach) and Dr. Brian (Director of Athletic Performance) to compare HRV guided training vs. pre-planned training in collegiate football players this offseason. We will test 1 rep maxes in the big lifts before and after and see which group made the greatest improvements. This is basically copying Kiviniemi’s design except we are measuring strength performance in football players as opposed to running velocity in endurance athletes.

I’m happy to say that the department of athletic performance are all on board to conduct this research though there is still much to be done in acquiring valid instruments, getting approval from the IRB and so forth. Fingers are crossed that we can get it done. This is not part of my graduate program as I’m completing a course work based Master’s rather than a thesis based one. This research will be entirely out of personal interest on behalf of myself and the participating staff at the school.

Weight Room

In my next post I will display nearly 7 months worth of data from my own personal HRV scores. It will be much more interesting than this post I promise.

Thanks.

References

Bosquet, L., Merkari, S., Arvisais, D., Aubert, A.E. (2008) Is heart rate a convenient tool to monitor over-reaching? A systematic review of the literature. British Journal of Sports Medicine, 42(9): 709-714.

Chen, J., Yeh, D.,  Lee, J., Chen, C.,  Huang, C.,  Lee, S., Chen, C.,  Kuo, T., Kao, C., & Kuo, C. (2011) Parasympathetic nervous activity mirrors recovery status in weightlifting performance after training. Journal of Strength and Conditioning Research, 25(6):  1546-1552

Cipryan, L., Stejskal, P., Bartakova, O., Botek, M., Cipryanova, H., Jakubec, A., Petr, M., & Řehova, I. (2007)  Autonomic nervous system observation through the use of spectral analysis of heart rate variability in ice hockey players.  Acta Universitatis Palackianae Olomucensis. Gymnica, 37(4): 17-21.

Hedelin, R., Bjerle, P., & Henriksson-Larsen, K. (2001) Heart Rate Variability in athletes: relationship with central and peripheral performance. Medicine & Science in Sports & Exercise, 33(8), 1394-1398.

Iellamo, F., Pigozzi, F., Spataro, A., Lucini, D., & Pagani, M. (2004) T-wave and heart rate variability changes to assess training in world class athletes. Medicine & Science in Sports and Exercise, 36(8): 1342-1346.

Kiviniemi, A.M., Hautala, A., Kinnumen, H., & Tulppo, M. (2007) Endurance training guided by daily heart rate variability measurements. European Journal of Applied Physiology, 101: 743-751.

Kiviniemi, A.M., Hautala A.J., Kinnunen, H., Nissila, J., Virtanen, P., Karjalainen, J., & Tulppo, M.P. (2010) Daily exercise prescription on the basis of HR variability among men and women. Medicine & Science in Sport & Exercise, 42(7): 1355-1363.

Nigam, A.K. (2010) Resting heart rate and overtraining in athletes. International Referred Research Journal, 2(21): 38-40.

Pichot, V., Busso, T., Roche, F., Gartet, M., Costes, F., Duverney, D., Lacour, J., & Barthelemy, J. (2002) Autonomic adaptations to intensive overload training periods: a laboratory study. Medicine & Science in Sports & Exercise, 34(10), 1660-1666.

Heart Rate Variability Explained: Part 1

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Edit 03/25/2014: For a more in depth discussion on HRV click here

To open my discussion on HRV and its potential usefulness in athletes I would like to first highlight some of HRV’s most promising attributes.

  1. HRV can help determine if and when one is overtraining
  2. HRV can inform you when you are more adaptive to training and when you are less adaptive (telling you when to train hard and when to back off)
  3. HRV can potentially predict if you will perform better or worse on a given day (I’m not sold on this yet)
  4. HRV pretty accurately reflects recovery status

If you take your sport/training seriously, this information is extremely valuable. Throughout the next few posts I will do my best to fully explain what HRV is, how it works and from there we will discuss how to put it to use practically. I would also like to mention that HRV can be effective in both strength and endurance athletes. In fact, the majority of the research that exists on HRV has been performed on endurance athletes. So if you are a runner, cyclist, rower or all of the above, this blog may still offer useful information.

By now you might be wondering what the heck is HRV exactly? HRV is the measurement of time between each heartbeat. If you thought that the heart beats on a fixed rhythm you are incorrect. The time interval between each heart beat is highly variable. Specifically, we’re talking about the measurement of time between each R-R interval from an electrocardiogram (ECG) measurement. The variability in your heart rate provides critical information about the function of your autonomic nervous system (ANS). Typically HRV is measured on an ECG in a clinical setting. Fortunately, other more affordable and accessible devices exist that will measure your HRV (I will provide more info on these later).

What is the ANS and why is it important?

Here’s where the discussion turns a little more technical but bear with me. The ANS contributes to the body’s homeostasis by exciting or inhibiting cardiac muscle, smooth muscle and glands in response to subconsciously perceived visceral sensations (Tortora & Derrickson 2006). The ANS is comprised of two branches; the sympathetic nervous system (SNS) and the parasympathetic nervous system (PSNS). The easiest way to distinguish the differences between these two branches is to associate “fight or flight” responses with the SNS and “rest and digest” responses with the PSNS.

Sympathetic activity increases heart rate, force of contraction and blood pressure; increases blood flow to your muscles while decreasing blood flow to your gastrointestinal organs and releases sugar into the blood to provide energy to the working muscles. Adrenaline and glucocorticoid hormones are released to enhance these actions. In essence, the SNS responds to stress by providing the body with the resources and ability to move quickly to safety or to fight in response to danger. Think about anytime you’ve felt an adrenaline rush before a big sporting event or when someone scared you. That is your SNS being activated.

In contrasts, the PSNS does the complete opposite. In the absence of stress the body will reduce your heart rate and blood pressure; increase digestive processes and focus on the build up and repair of tissues (such as muscle) and storage of sugar (glycogen). In essence it recovers the body from any damage done during the stress response of the SNS.

Our SNS is activated when we train or compete. This is a good thing as it will enhance our ability to perform. However, intense training is extremely stressful on the body and requires sufficient recovery. It is important to understand that the acute response to a heavy strength training workout is actually weakened and damaged muscle tissue and a fatigued central nervous system. This is why we need to allow for sufficient recovery time to let the parasympathetic nervous system mobilize adaptive reserves and repair our muscle tissue and thus bring us to an increased level of strength.  An imbalance between sympathetic and parasympathetic activity can lead to reductions in performance and in severe cases, overtraining.

Enter HRV. HRV provides a non-invasive look at the function of our autonomic nervous system. If our body is still stressed from training it will be reflected in our HRV. Alternatively, if we are sufficiently recovered from training it will also be reflected in our HRV. Training intensely when HRV scores are poor would be counterproductive. When HRV scores are high, intense training will be well tolerated because adaptive reserves are high.

Keep in mind that it is not just training stress that the body must recover from. Any form of stress, be it mental or physical will use up adaptive reserves and elicit a stress response. Money problems, fighting with your significant other, moving to another city and so forth can all be extremely stressful on the body. HRV will be effected by any stressor making it all the more valuable to monitor. In future posts I will discuss how different non-training related events have significantly affected my HRV scores.

I will wrap this post up here as this can be a lot to swallow for anyone without a background in human physiology. In my next post I will discuss some research that supports the claims I made earlier about HRV.

Reference

Tortora, G. & Derrickson, B. (2006) Principles of Anatomy and Physiology 11th Edition. Biological Sciences Textbooks Inc.