I hope it’s valuable information and easy to understand. So as not to overwhelm anyone, there will be two other segments where I’ll answer more specific questions around HRV and utilizing it in training.

 

The world of training is evolving. 10 years ago, the idea that sleep was a crucial factor for performance was known but the amount of coaches who talked about it with their clients or teams was negligible. Now, everywhere you turn another coach is talking about sleep, breathing, heart rate variability (HRV), some cool new gadget or piece of tech that will better allow them to track and monitor the workload of their clients. Unfortunately, the buzzwords and catchphrases seem to be the bulk of the knowledge most coaches can give. This can (and has) led to confusion, misinterpretation and, in the case of HRV, concern over the data people are getting to look at and make decisions based on. I wanted to dive into HRV a bit and give what I hope is helpful information. Part 1 will talk about the basics of HRV and part 2 will discuss the more individual and specific concerns people have. 

 

So what exactly is HRV?

Heart rate variability, HRV, is a measure that describes the beat-to-beat variation in your heart rate. Our heart does not beat at a consistent rhythm. No, I’m not talking about the increase in your heart rate when you workout or are scared, I mean that when you are at rest and your heart rate is 60 bpm, heartbeats are not spaced out in one second intervals. Some are spaced out at intervals of .7 seconds, some at 1.3 seconds, but overall, over the course of a minute your heart beats 60 times. These variations between .7 and 1.3 seconds are measured and averaged out over the course of a minute to give you your HRV reading.

 

Ok but what does that mean? Why should I care?

Our body is constantly trying to maintain a systemic balance. Hormone levels, blood pressure, food digestion, core temperature, etc are always in flux and our body is always working to maintain a sense of balance and normalcy. This is done through the parasympathetic (pNS) and sympathetic nervous systems (sNS), the “rest-and-digest” and “fight-or-flight” systems. Among other systems they control, both the pNS and sNS influence the heart and how fast or slow it beats. HRV is an accessible and easy way to roughly measure this interplay between these two systems. In general, a higher HRV means that the pNS is more dominant at the moment (your more relaxed/less stressed) and lower HRV means that the sNS is more dominant (higher stress or anxiety). 

 

So high HRV is good and low HRV is bad. What determines my HRV?

HRV is determined by the interplay of the pNS and the sNS. The more stressed we are, the more the sNS has influence, the less stressed and better rested we are, the more the pNS has influence. So if stress is the main influencer, this really means that HRV is showing us how well we are dealing with stress. Stress includes physical stress, like exercise, and emotional stress, like worry and anxiety. But in addition to those, stress can also come in the form of poor diet, excessive alcohol, smoking, illness, lack of sleep. Environmental factors such as air quality, altitude, extremes in weather can all be counted towards “stress”. Stress is reduced through sufficient sleep, proper nutrition and hydration practices. Disconnecting and just spending time in nature can also reduce stress. 

 

This is why HRV is always seen in the context of recovery, or how well we are adapting to the stress we are putting our body under. For athletes, it helps them see how well they are adapting to a training load or how well they are recovering leading up to a big competition. For the non-athletes among us, HRV is a good feedback tool that lets us see how our body is adapting/managing the lifestyle we are leading.

 

In part 2 I’ll go through how we should read our HRV and factors that might cause a specific type of trend. Part 3 I’ll go over specific questions from people I have worked with and ones that I have seen asked frequently.