You may simply track your own health indicators at home with the aid of your phone, Apple Watch, or Fitbit. Fitness and technology go hand in hand. But knowing what to track is just as important as having the appropriate tools.

Heart-rate variability, or the time between heartbeats, is an important health metric that many people aren't yet tracking. This test, sometimes referred to as HRV, can reveal details about your general health, level of stress, amount of exercise, and much more. Since not all wearables enable HRV, it is more challenging to monitor it than your typical heart rate or pulse.

One of the few wearables that monitors HRV is the Whoop tracker, which uses it along with a few other factors to help assess whether you are adequately recovered from your most recent workout to perform extra training. Because of these particular measures, professional athletes and endurance trainers are major proponents of the product. In actuality, I didn't learn about HRV until I took a look at the Whoop band on the company's website.

Like any other measure provided by fitness trackers, HRV is essentially meaningless unless you know what it means and how to apply it to better your fitness and health. To learn more about HRV, how to test it, and how it can help you improve your health, continue reading.

According to Holly Roser, a certified personal trainer, 'HRV is the interval between each heartbeat, which is governed by the autonomic nervous system.' The parasympathetic and sympathetic nervous systems, which make up the autonomic nervous system, are basically your body's stress or nervous system regulators.

The nervous system is crucial because it controls your body's automatic functions, including your heart rate, digestion, and blood pressure. The sympathetic nervous system reaction, often known as your stress response or what puts you into 'fight or flight' mode, is what you can conceive of. The 'rest and digest' state, also known as the parasympathetic nervous system response, is crucial for allowing your body to digest food and for bringing your heart rate and blood pressure down.