Recent years have seen an influx of devices measuring HRV (Heart Rate Variability) on the market. You may even have that feature on your smartwatch and not know it. What is HRV and how is it useful to triathletes?
If you’re coached by a Team Atomica coach, recovery weeks are part of your plan, allowing anaerobic and aerobic adaptations to occur, leading to improved performance. But, finding the ideal balance of training and recovery is very individual and depends on many factors beyond the physical. Moreover, it can fluctuate daily.
There are a number of training metrics in the industry that aim to quantify just how much stress/workload athletes are enduring. These tend to incorporate a variety of readings such as the Training Stress Score (TSS) on TrainingPeaks, the results of which can sometimes be unclear, relying as it does on duration, normalized power, average heart rate, as well as an athlete’s FTP, and the IF (Intensity Factor) of a given workout. For example, sometimes a short hard track workout might yield a significantly lower TSS than say, a medium long run.
By contrast, tracking HRV can potentially be much more precise in registering just how recovered you are. Among endurance athletes over the last few years, two brands have dominated HRV tracking, and for good reason. The WHOOP and the Oura Ring provide (by most accounts) the most accurate data.
Heart Rate vs Heart Rate Variability (HRV)
When we use Heart Rate to quantify efforts in training, we are referring to the number of heartbeats per minute (bpm). The space between those heartbeats varies and is determined by our autonomic nervous system. The variability of that spacing is referred to as HRV. Any high stress scenario (think sympathetic nervous system “fight or flight” responses) will increase HR and the parasympathetic nervous system drives the “rest and digest” response, thereby decreasing HR. Both are at play in HRV.
In general, variability is good as it means the cycles of work and recovery are happening. We are in a state of high stress when the variability between successive heartbeats is low, such as during a heavy training block. A consistently low HRV reading suggests overtraining, fatigue (lack of sleep), and other external stresses that are compromising the system. By contrast, high HRV readings point to higher parasympathetic activity—states of low stress.
Tracking HRV is useful for optimizing the training cycle and can help you and your coach detect when you might be getting sick, when you need to shift a recovery week, or simply modify your plan. But it can also boost your confidence going into a race when, for example, you experience the “blahs” of tapering. A solid HRV reading can help you stick to that tapering plan.
If you’re interested in tracking HRV, it is important to establish a baseline and to take readings under the same conditions every time (such as in the morning before breakfast and seated or lying down). Doing so could help you maximize your training and racing.