There are many metrics we can keep track of these days to help guide us toward better health and fitness. We can use metrics from fitness trackers such as the Fitbit, Apple Watch, Garmin, Whoop, Morpheus, etc. The list of products and the data they give you go on and on, but how do we actually use this data to improve our health and fitness? What data is most important for us to track?

These devices most commonly track things like steps, sleep quality, food, and heart rate. But if you’re exercising at a moderate to high-intensity regularly, there is one specific metric you should be paying attention to more so than the others. This metric is known as Heart Rate Variability or HRV.

HRV is a great measure to keep track of if you’re a regular exerciser, because you can use it to gauge your readiness for another workout. It will give you an idea if you should be hitting the gym hard again or if you should maybe take it easy and rest or do a lighter recovery workout.

So, what exactly is HRV?

To put it in as simple terms as possible, there is a certain amount of time that goes by from one heart beat to the next (measured in milliseconds, or ms). HRV represents the variations in these time intervals that occur from beat to beat. Here’s a visual representation of what that may look like. So, if you have a high HRV, these time intervals will vary a lot (i.e. be different), and if you have a low HRV, these time intervals will be very similar.

HRV will tell you how balanced your Sympathetic Nervous System (SNS) (i.e. fight or flight mode) and Parasympathetic Nervous System (PNS) (i.e. rest and digest mode) are. In general, if you are SNS-dominant (i.e. lower HRV) you are in a slightly-stressed state, and you would be better off taking the day off and focusing on activities that enhance your recovery such as meditation, yoga, tai chi, or just getting more quality sleep. If your HRV is higher, this is an indicator that your SNS and PNS are balanced, you are more resilient, and you can most likely handle a more stressful workout.

How can you measure and use HRV?

There are many apps and products out there that can measure HRV, and they all have their own ways of quantifying it, some of which use the same algorithms. Some of these products include Whoop, Morpheus, Oura Ring, and Elite HRV.

Whoop and Morpheus are both wearable fitness trackers that measure HRV on the wrist, but are also compatible with chest straps, which are more accurate, considering that they sit really close to the heart. The Oura Ring is a relatively new product that measures HRV through the arteries of the finger. Elite HRV is an app that is compatible with certain chest straps and will give you an HRV score as well.

As stated previously, these wearables and apps measure HRV in different ways, but the important thing to remember is that you should be tracking your HRV compared to your baseline levels over time (i.e. weeks and months).

If you wake up one morning and see that your HRV is much lower than usual, you should use this information to guide your decision on whether or not you should push yourself hard that day. If your HRV is low for an extended period of time, you also risk some negative health consequences. You want to shoot for a higher HRV compared to your baseline. Some days will be lower and some will be higher. You won’t always be feeling top-notch.

This is just another great metric you can use to gauge your readiness to perform another tough workout at the gym.

Check out the resources below to take a deeper dive into HRV.

Got questions? Leave a comment below.

References

Stress and Heart Rate Variability

Sleep and Heart Rate Variability

What is HRV and What Can You Learn From It?

More about HRV