There always seems to be something new to measure when it comes to athletics. As we understand more and more about what impacts athletic performance, we also discover new metrics to help optimize training. The latest data point that is emerging as a go-to metric is HRV, which stands for Heart Rate Variability. So what is it and why should you care? Read on!
The topic of HRV tends to be highly technical, but I'm going to try to distill it to a few very core basic principles as it relates to training. There are plenty of resources out there if you want to dive into the technical aspects - this post can be a good starting point if you want to dive into more technical aspects later.
HRV as a Signal of Fight-or-Flight and Relaxation Responses in the Brain
To explain HRV simply, it is simply a measurement of the variation of time between each heartbeat. These variations are normal, and controlled our autonomic nervous system (ANS), which is just fancy talk for the part of our brain that is also known as the part that is involved in our 'fight-or-flight' and 'relaxation' responses.
These two systems are impacted by a variety of things in our day-to-day life, including; stress, sleep, diet, relationships, isolation, exercise (or lack of) and more. HRV is a way that you can identify any imbalances or concerns about your well-being, which for a training program can mean identifying when you need extra rest, should scale back a workout, or even take a day off to prioritize recovery and sleep.
The Difference Between HRV and Measuring Resting Heartrate
One of the tried-and-true training metrics that I always tracked was resting heartrate - if I saw a spike in my resting heartrate, I knew I had to keep an eye on recovery. Often, a spike in resting heartrate can indicate an incoming sickness, and if you catch it before you are symptomatic and prioritize sleep and recovery instead of training, the length of the sickness is often cut down significantly than if you trained up until actually feeling sick.
The only problem was that my resting heartrate fluctuations weren't accurate enough to distinguish between building up the fatigue necessary for fitness gains and actually getting sick. Sometimes my resting HR would spike, but I could train through it to build some fatigue for endurance. Other times, a spike in HR meant I was about to come down with a serious man-flu.
HRV gives a more detailed and accurate picture to understanding whether you should continue stacking on training, or take a break, and the more I've used it and compared it to simple resting heartrate, the faster I find HRV will signal a need for a break.
Getting Started with HRV and Applying it to Training
All you need to get started with HRV is a heart-rate strap accurate enough to pick up on the minor variations in your heartbeat (which almost all modern straps do), and an app or data dashboard capable of analyzing and showing your HRV. I use Elite HRV on my phone paired to a Wahoo Tickr strap, but any HRV program and strap should do.
From there, you need to get in the habit of measuring your HRV, at the same time, in the position, everyday to establish a baseline. HRV can vary based on time of day and your position, so it's important to keep things consistent.
I take my HRV reading first thing in the morning, sitting up in bed, before getting up to start my morning. I find this the easiest way to ensure consistency.
The Elite HRV app is a very intuitive platform that does all the thinking work for you, and after enough days of establishing your baseline, it will display your data visually after each reading, giving you a simple colored gauge and a number on 1-10 showing your 'readiness' for training that day.
Above are just a few screenshot examples from the app shown after an HRV reading is taken. Green means all is good, yellow means some caution may need to be taken (aka no high-intensity intervals) and red means definitely take a break and cancel any training intensity.
As you get more familiar with the concept, the Elite HRV app shows far more data for your own interpretation if you want, but I find that even just by using the simplified colored gauges, it is an incredibly valuable tool for training.
Have you measured your HRV before? How do you use it for training? Comment below!