Toolbox: Heart Rate Recovery Metrics
Training and performance are often referenced as points on a continuum. Each day you begin your training at a certain level of freshness and fitness intent on achieving the most bang for your training buck. But are you shooting fish in a barrel or shooting yourself in the foot?
By Matt McNamara
Is my training effective? It is a common question that has many potential answers ranging from tactical and strategic to hard numbers from your power meter, your heart rate monitor or your own self-reporting. In my coaching I try to arm my athletes with as many beneficial options as I can. These days that includes revisiting heart rate and recovery as a measure of merit.
Recovery, as defined last time, is the process of returning the body to a normal state. To that end we outlined a few of the common recovery refrains: sleep lots, eat within 90 minutes, get a massage, and rehydrate. With the help of some industry heavies, we brought the concept of recovery full circle by referencing performance and the ability to repeat (and improve) bouts of exercise as the real world proof that recovery had, in fact, occurred. To this was added subjective feedback from the athlete as measures of merit.
The logical next step is to provide some objective measures that you can use to gauge your recovery, and some tools that may facilitate that recovery. Let’s look at a couple of approaches to monitoring recovery that are built around heart rate.
Heart Rate Variability
Two of the more intriguing developments in performance recovery management come from the medical field; the concepts of Heart Rate Variability (HRV) and Heart Rate Recovery (HRR). HRV has long been used as a reference point for the established and significant relationship between the autonomic nervous system (ANS) and cardiac mortality. Heart Rate Recovery is often used in a medical setting to assess cardiac health in at risk populations. Both are built on the premise that the ANS, consisting of sympathetic and parasympathetic components, provides a unique insight into the effects of training by way of its responsiveness and interconnection with other physiological systems.
Heart Rate Variability is measured as the time/gap between heart beats, also known as the RR interval. The RR interval looks like this:
Heart rate variability, as the name suggests, is calculated from how regular your heart beats in time.
HRV theory says that with an increase in training load the sympathetic nervous system (SNS) becomes more reactive, elevating resting heart rate and increasing the HRV. The argument is that by tracking ones HRV across time an athlete is better able to monitor and plan their training to match physiological capacity, or how much stress is being placed on their central nervous system.
To date there have been a few studies using HRV as a primary measure, indeed a keyword search of the PUBMed database didn’t return any specific research looking at heart rate variability and cycling performance (although there was one study looking at HRV and cadence).
There are a couple of companies that are using HRV-derived values for tracking athlete performance across time. Since I don’t have a full evaluation of these systems I’ll defer to the future for a look at these innovative options.
Heart Rate Recovery
Heart Rate Recovery (HRR), on the other hand, is defined as the reduction in heart rate within the first 60 seconds after the completion of a maximal, or nearly maximal, workload. In 2010 a study by Lambert, Swart, et al looked at the efficacy of HRR as a monitoring option for athletes taking part in a 4-week High Intensity Training study.
They broke their athletes into two groups – Increasing HRR (meaning their HR dropped more) and Decreasing HRR (less drop in HRR over time). The protocol consisted of a 4- week training block of two HIT sessions, two 90-minute recovery rides and three rest days. 40 km time trials were completed at the beginning and end of the study. The subjects also completed peak power test before and after the training block for comparison. HIT sessions consisted of 8×4-minute intervals at 80% of peak power, with 90 seconds of rest between efforts.
The improved 40 km TT times for the group with continually increasing HRR values was the primary finding of the study. While this is somewhat unsurprising, considering the trending of increased fitness being reflected by an increasing HRR value, it was surprising that the HRR decreasing group reached a seeming plateau after the 6th HIT training bout. Surprising, in part, because the Decreasing group was younger and “fitter” (higher relative VO2max values) than the Increasing group. Perhaps these athletes came into the trial a bit closer to overload, or maybe they trained more than they were supposed to – whatever the reason, it was an interesting outcome. The practical application is that a larger drop in heart rate represents better fitness and recovery.
One factor thought to contribute to red blood cell production is Human Growth Hormone (HGH). Sleep has been shown to have a positive effect on HGH secretion, especially as you enter a third REM (Rapid Eye Movement) cycle.
While there are any number of self report metrics that have been used across time to try and quantify, and understand, an athlete’s recovery, the true value of these is somewhat limited without a reliable objective measure to cross correlate with. Measures like the Profile of Mood States (POMS), Rating of Perceived Exertion (RPE) and sleep pattern qualification have proven to be fairly robust when applied consistently across time, the need for a useful metric that reflects actual physiology is legitimate.
Several promising tools have shown crossover potential from the medical population to the athletic one. These include Heart Rate Recovery and Heart Rate Variability, two measures that aim to quantify recovery, and importantly potential for future training modification (up or down). Both systems rely on the Autonomic Nervous System to help paint a picture of recovery built around the moment to moment variation in heart rate values. HRR looks at how quickly heart rate falls at the cessation of intense exercise (more drop is better), while HRV looks at the changing relationship of the heart’s contraction over time, related to a baseline. Both need more quality research, but each presents a potentially novel approach to understanding the role of recovery in performance.
1. Guidelines for Heart Rate Variability: Standards of measurement, physiological interpretation, and clinical use. Task Force of The European Society of Cardiology and The North American Society of Pacing and Electrophysiology. European Heart Journal (1996) 17, 354–381
2. Heart rate variability and physical exercise. Current status. Hottenrott, Hoos, Esperer.
Institut fьr Sportwissenschaft, Martin-Luther-Universitдt Halle-Wittenberg, Halle-Wittenberg.
About Matt McNamara: Matt is a USA Cycling Level 1 coach with over 20 years of racing, coaching and team management experience. He is the founder and president of Sterling Sports Group. If you have any questions or comments please feel free to contact him directly at [email protected] You can learn more by visiting his website at www.sterlingwins.com.