We know that each athlete’s ability to be ‘on’ every day for months on end is zero. We all have good training days and bad training days because we’re human. What if coaches, trainers, and athletes could know when the athlete is going to have a great work out and give them the appropriately hard training session knowing they’re going to crush it? What if coaches, trainers, and athletes could know when the athlete is going to have an off day and could give them the appropriate recovery workout? That would powerful.
Taking an accurate measurement of your physiological response to training is now possible through daily heart rate variability (HRV) monitoring using a smart phone (1). HRV monitoring can take a snapshot of the body’s autonomic nervous system, our unconscious master controller of physiological functioning. This is an easy, non-invasive, and accessible way for coaches and athletes to see how the stress of training is affecting their physiology. If a coach or athlete is not monitoring HRV, they are merely guessing at how effective their training program is.
The guessing method has, in general, helped athletes and coaches push the limits of our physical capacities. But can we do better in our preparation for performance? Can we maximize each individual’s genetic potential more effectively, more intelligently with less guessing? Each athlete’s training capacity can demonstrate a relatively high amount of variability throughout the preparation period leading to their primary race. Based on the standard training model, athletes could be training above or below their capacity to tolerate necessary training loads.
Currently, HRV monitoring allows the coach and athlete to know when the athlete is potentially falling into overtraining (7) as well as to prevent injuries (6). But as someone recently asked me – can taking your daily HRV actually improve performance? Well…good question.
Studies are starting to trickle in that HRV monitoring can not only prevent overtraining but can indeed improve performance. Researchers are calling it an ‘HRV-guided, day-to-day periodization’ model. Instead of the conventional meso/macro/micro cycle of training periodization – where an athlete does the prescribed training no matter what for an ‘X’ amount of weeks and months – a coach would prescribe the days training based off of the athlete’s daily ability, or readiness, to perform that training. There are a number of studies across different sports that have been researching the topic. Let’s go over some of the studies to get an idea how daily physiological monitoring can improve overall performance.
2019 – Cycling (2)
Tools such as HRV will allow us to take the principle of individualization a step further.
Researchers at the Sports Research Center at the University of Elche in Spain and the Institute of Sport and Exercise Medicine at Stellenbosch University in South Africa took cyclists who had a decade of training under their belt and trained them for 8-weeks. They tested them on a 40-minute time trial before diverging off into experimental (HRV group) and control groups (no HRV guided training). The cyclists were tested again after the 8-weeks of training. The HRV-guided group improved average power output on time-trial by 7.3% vs 4.5% for the traditional group.
How did the HRV-guided group improve during the 8-weeks of training? They, on average, did LESS moderately intense training. The two groups performed almost the same amount of volume (the HRV-guided group performed slightly more volume of work) but when comparing total amount of time spent going easy, moderate, or hard, the HRV-guided group did more training at an easy pace and the same amount of training at an intense level.
The researchers concluded the sameness of “traditional training programs produces different levels of response and adaptation of the athletes, preventing the individualization and adjustment of the training load, which would be obtained using the HRV as a tool to control adaptation. Therefore, tools such as HRV will allow us to take the principle of individualization of the load a step further.”
2016/2017 – Running (3,5*)
HRV monitoring can optimize the timing of vigorous training sessions.
Researchers at the Institute for Olympic Sports and the University of Jyväskylä in Finland took 20 women and 20 men and again trained athletes for 8 weeks. Before and after the prescribed training the two groups performed a 3-kilometer time trial, amongst other measurements (VO2max, lactate thresholds, etc.). Results showed, on average, a 14.3 second drop in time in the HRV-guided group compared to an average drop of 7.8 seconds in the control group.
How did this HRV-guided group improve during their 8-weeks of training? Same outcome: the HRV-guided group did LESS moderate training. BUT, in this study, the HRV-guided group also did LESS high intensity training, on average (1.8 vs 2.8 intense sessions/week).
The researchers concluded: “the timing of moderate and high intensity training sessions according to HRV is more optimal compared to subjectively predefined training. Therefore, HRV shows a potential tool in endurance training prescription by optimizing the timing of vigorous training sessions.”
*Just going to discuss study (3). Same result for study (5), HRV-guided group did better.
2018 – Nordic-skiers (4)
Researchers from the National Ski-Nordic Centre and the Institute of Sport Sciences at the University of Lausanne tested 24 elite Nordic-skiers and trained them for three weeks. These athletes were members of the cross-country ski and Nordic-combined French national team and were already highly trained athletes with little room for more improvement. Nonetheless, the HRV-guided group improved performance in a 10k roller ski test by 2.7% and an incremental treadmill test to exhaustion by 6.8%. The control group did not improve in either test.
During the first 15 days of training, only 3 days were adjusted due to lower HRV measurements compared to the control group (so 20% of workouts were adjusted for the HRV-guided group). The researchers reported no significant differences between groups in the time spent training in the different intensity zones.
The researchers concluded that the improved performance and oxygen consumption (VO2max) in the HRV-guided groups confirm the effectiveness of HRV monitoring even in elite endurance athlete.
Other Sports (5, 6)
An HRV-guided, day-to-day training regimen has also been shown to be superior in CrossFit when compared to traditional periodized models. I've posted the articles below if you wish to look at them.
Coaches, what is the value here? The value is it is now possible to give the right training stimulus to an athlete on any given day. The value here is the ability to make you, the coach, more effective by understanding your athlete’s physiology and how they’re adapting to YOUR training regimen. HRV monitoring is the way to quantify how your athletes are feeling and their nervous system’s readiness to train hard. Empirical data can now be used to predict how athletes are going to perform when they show up for a workout. The value here is that HRV-guided, day-to-day training allows the athlete to have MORE successful training days because we now know when their nervous system can handle the hard training. As the studies are showing, this results in better performance at the end of the season.
Athletes, what is the value here? HRV-guided, day-to-day training puts objective data into why and how you can train on any day, which helps you to interpret your own intuition of how you feel you’re doing. You can make more sense of what you should do if a training session feels off, or conversely helps to explain why one day you may think you’re going to be sluggish but end up rallying. The value here is simply training smarter so that you show up to the starting line knowing you’ve trained your best.
Coaches, trainers, and athletes: we are still in the dark ages of optimizing training. We have a long way to go before we are able to prescribe the exact, down to the minute, volume and intensity necessary for optimal training stimulus. That day is coming. HRV monitoring and day-to-day workout design is the future of training.
Dobbs, W. C., Fedewa, M. V., MacDonald, H. V., Holmes, C. J., Cicone, Z. S., Plews, D. J., & Esco, M. R. (2019). The accuracy of acquiring heart rate variability from portable devices: a systematic review and meta-analysis. Sports Medicine, 49(3), 417-435.
Javaloyes, A., Sarabia, J. M., Lamberts, R. P., & Moya-Ramon, M. (2019). Training Prescription Guided by Heart-Rate Variability in Cycling. International journal of sports physiology and performance, 14(1), 23-32.
Vesterinen, V., Nummela, A., Heikura, I., Laine, T., Hynynen, E., Botella, J., & Häkkinen, K. (2016). Individual endurance training prescription with heart rate variability. Medicine and science in sports and exercise, 48.
Schmitt, L., Willis, S. J., Fardel, A., Coulmy, N., & Millet, G. P. (2018). Live high–train low guided by daily heart rate variability in elite Nordic-skiers. European journal of applied physiology, 118(2), 419-428.
Nuuttila, O. P., Nikander, A., Polomoshnov, D., Laukkanen, J. A., & Häkkinen, K. (2017). Effects of HRV-guided vs. predetermined block training on performance, HRV and serum hormones. International journal of sports medicine, 38(12), 909-920.
Gisselman, A. S., Baxter, G. D., Wright, A., Hegedus, E., & Tumilty, S. (2016). Musculoskeletal overuse injuries and heart rate variability: Is there a link?. Medical hypotheses, 87, 1-7.
Morgan, S. J., & Mora, J. A. M. (2017). Effect of heart rate variability biofeedback on sport performance, a systematic review. Applied psychophysiology and biofeedback, 42(3), 235-245.
Ortega, E., & Wang, C. J. K. (2018). Pre-performance Physiological State: Heart Rate Variability as a Predictor of Shooting Performance. Applied psychophysiology and biofeedback, 43(1), 75-85.
Chrismas, B. C., Taylor, L., Thornton, H. R., Murray, A., & Stark, G. (2019). External training loads and smartphone-derived heart rate variability indicate readiness to train in elite soccer. International Journal of Performance Analysis in Sport, 19(2), 143-152.