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!

Have a good weekend!