Exam Stress Impact on HRV and the Immune System: Implications for Student Athletes

The importance of academic examination periods for student athletes at both the high school and collegiate level cannot be overstated. In most cases, academic performance can affect scholarship money (in the collegiate setting); playing time; academic standing (probation) and so forth. Any former athlete can probably attest that exam weeks involve a lot of cramming, plenty of caffeine, suboptimal eating habits and sleep deprivation. Needless to say, the added stress load from exams and exam preparation can have consequences on physical health and possibly performance. In this discussion I will review the available literature pertaining to exam periods and HRV in students to determine its potential usefulness at reflecting this stress. In addition, I will present and discuss some data I’ve collected from a couple of students during their recent exam weeks.

*Note: Very little of the research specifically involves student-athletes.

Perhaps one of the more interesting studies involving college students over exam periods was performed by Dimitriev et al. (2008). Female students (n=70, Age 20-25) were evaluated twice; once during the semester and once on the morning of examinations. Data on HRV, blood pressure, state anxiety and self-reported test performance (how they expected to perform on the exam) was collected. Essentially, students who performed the best on exams were the most pessimistic and showed the largest decrease in parasympathetic indices of HRV (HF and RMSSD). Students who performed best on the exams tended to have a higher state anxiety compared to during the semester while poor performers showed less state anxiety and less change in HRV.

Srinivasan et al. (2006) evaluated perceived stress and HRV in 36 male and female first year med students. A strong correlation was found between the high stress group and LF and LF/HF HRV parameters. Though not statistically significant, there was also a tendency for lower HF values among the high stress group. Kumar et al. (2013) also reported reductions in HRV in med students over exams compared to periods of lower stress before and after exams.

In a study by Tharion et al. (2009) a group of 18 undergraduates (9 male, age 18.7) had HRV and blood pressure assessed on the morning of examination (high stress) and one month later during holidays (low stress). As expected, during the exam period students showed lower HRV (total variability of both time and frequency domain). Interestingly changes in LF, HF, LF/HF and RMSSD were not statistically significant, though there were differences. These changes are likely still meaningful.

An investigation involving 20 female undergrads (age 18-19) showed that compared to the non-exam period, HRV parameters gathered during exams decreased (RMSSD, HF, with increases in LF and LF/HF) indicating a withdrawal of parasympathetic modulation and increase in sympathetic tone (Zaripov & Barinova, 2008). This was despite no changes in perceived stress during exams. Simic and colleagues (2006) reported a linear increase in perceived exam apprehension leading up to exams while HRV reached lowest values during exams and  increased thereafter.

This next study did not include HRV analysis however I felt it was worth including. Kang et al. (1997) collected blood samples from 87 high-school students at mid-semester, final exams and post-exams to assess immune responses to the academic stressor. Results showed that during the exam week there were significant immunological alterations; “Natural killer cell activity was significantly lower, whereas lymphocyte proliferation and neutrophil superoxide release were significantly higher. These immune changes tended to return toward baseline during the postexam period, but the enhanced neutrophil reactivity continued to rise.” Another study involving first year med students also found a strong link between stress related immunosuppression and health based on blood sample assay.

Athletes may be at greater risk of immune suppression compared to non-athletes because of the physical demands (strain, monotony) of their sport participation (Putlur et al. 2004). Enforcing responsible exam preparation will increase likelihood of exam performance and reduce the need for procrastination which is a major contributing factor to stress among students (Tice & Baumeister, 1997).

Data from a High School Football Player Over Exams

  • Exam week occurs in the last week of the ithlete trend below.
  • Following Monday, HRV remains well below baseline until Saturday
  • Poor sleep due to late nights studying
  • Though the athlete is currently involved in various Track & Field events as well as summer football, he had no competitions during exam week.

VL_Exam

Below is the weekly mean HRV in the 3 weeks prior to and the exam week.

  • HRV weekly mean does not reflect the acute stress experienced by this athlete day to day (a limitation of only assessing weekly mean)
  • Overall the exams appeared to be only a moderate stressor for this athlete
  • I included reaction test data because it was available; interestingly it was also effected (slower) during exam week
  • See here for more details and info on the Reaction Test

V_Exam_Big_Trend

I have included solo charts of the HRV and Reaction trend because I continue to see a consistent negative correlation between  HRV weekly mean and Reaction weekly mean. These charts reflect this relationship better than the above chart.

V_Exam_HRV_AVG

Weekly Mean HRV Trend

V_Exam_Reaction_AVG

Weekly Mean Reaction Time Trend

Data from a Grad Student Strength Coach in the Final Weeks of School

Below is the ithlete HRV data from a colleague who had a very stressful last month of grad school.

  • Week 1 represents baseline
  • Week 2 is the week before major presentations and a research paper due date. He reports this week to be highly stressful
  • Week 3 -5 include presentations, final exams, research paper deadlines, etc.
  • Week 6-7 represent the ascent in his HRV trend back to baseline after completing his school work.
  • Both the weekly mean trend and the daily trend provide a good reflection of his perceived stress
J_dailyHRV_exams

Daily HRV Trend

J_weeklyHRV_exams

Weekly Mean HRV Trend

Closing Thoughts 

Not surprisingly, exam periods are stressful for students. HRV appears to do a reasonably good job of reflecting this. However, responses tend to be individual with some students being more effected than others. If competitive seasons conflict with examination schedules, coaches may want to consider reducing training loads or at the very least, keep a closer eye on fatigue and stress in their athletes. Using a proactive approach by enforcing responsible exam preparation far enough in advance (study hall, tutoring, etc.) should reduce potential stress related issues by discouraging procrastination and associated changes in life style. Of course this is much easier said than done.

References

Dimitriev, D. A., Dimitriev, A. D., Karpenko, Y. D., & Saperova, E. V. (2008). Influence of examination stress and psychoemotional characteristics on the blood pressure and heart rate regulation in female students. Human Physiology, 34(5), 617-624.

Glaser, R., Rice, J., Sheridan, J., Fertel, R., Stout, J., Speicher, C., … & Kiecolt-Glaser, J. (1987). Stress-related immune suppression: Health implications. Brain, behavior, & immunity1(1), 7-20.

Kang, D. H., Coe, C. L., McCarthy, D. O., & Ershler, W. B. (1997). Immune responses to final exams in healthy and asthmatic adolescents. Nursing research46(1), 12-19.

Kumar, Y., Agarwal, V., & Gautam, S. (2013). Heart Rate Variability During Examination Stress in Medical Students. International Journal of Physiology, 1(1), 83-86.

Putur, P. et al. (2004) Alteration of immune function in women collegiate soccer players and college students. Journal of Sports Science & Medicine, 3: 234-243.

Shrinivasan, K., Vaz, M., & Sucharita, S. (2006). A study of stress and autonomic nervous function in first year undergraduate medical students. Indian Journal of Physiology & Pharmacology, 50(3), 257.

Simić, N. (2006). Evaluation of examination stress based on the changes of sinus arrhythmia parameters. Acta Medica Croatica 60(1): 27.

Tharion, E., Parthasarathy, S., & Neelakantan, N. (2009). Short-term heart rate variability measures in students during examinations. Natl Med J India, 22(2), 63-66.

Tice, D. M., & Baumeister, R. F. (1997). Longitudinal study of procrastination, performance, stress, and health: The costs and benefits of dawdling. Psychological Science, 454-458.

Zaripov, V. N., & Barinova, M. O. (2008). Changes in parameters of tachography and heart rate variability in students differing in the level of psychoemotional stress and type of temperament during an academic test week. Human Physiology, 34(4), 454-460.

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About hrvtraining

I hold an MS in Exercise Science and am a CSCS with the NSCA. I"m currently working in the Human Performance Lab at Auburn University (Montgomery) completing several research projects on HRV and exercise. I will be pursuing a PhD in Human Performance this Fall (2014) at the University of Alabama. Formerly, I worked as an assistant strength and conditioning coach at Cal U in PA. I have an extensive athletic background including hockey, rugby and collegiate football. I now compete in raw powerlifting and was the 2010 Canadian National Champion (amateur). I am interested in all aspects of strength and conditioning however my research interest pertains to heart rate variability and its application to monitoring the training of athletes.
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5 Responses to Exam Stress Impact on HRV and the Immune System: Implications for Student Athletes

  1. Vlad says:

    You wrote in the beginning on the article about higher performers having lower HRVs. Would waking on the morning of the exam with a low HRV be conducive to exam performance? What if one did some relaxed breathing to shift towards the parasympathetic system and increase the HRV? Would you expect this to lower test scores?

  2. hrvtraining says:

    Hi Vlad,

    In that study the high performers showed the most anxiety which would obviously result in lower HRV. I think they performed better because they cared more about the exam and likely studied more as a result. Those who performed poorly tended to have less anxiety and higher HRV. Perhaps they were a little more indifferent and less focused or concerned about their grades. I’m not sure how much of an effect manipulating HRV would have on exam performance in the grand scheme of things. You either study and know the material or your don’t. I would not expect to see a decrease in scores by simply altering breathing patterns to increase parasympathetic tone.

    Open to your thoughts,

    Andrew

  3. Pingback: How to Increase Your Heart Rate Variability

  4. Pingback: How to Increase Your Heart Rate Variability - HealthnExercise.com

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