Heart Rate Variability (HRV) is an important indicator of health and fitness. The metric has been around for a while but its only now that its gaining more attention. This is because HRV is becoming more accessible to the average person and not just medical professionals and fitness pros.
When you measure your heart rate, you will get a beats per minute value. At rest, this ranges between 60 and 80 for most people. The fitter you are, generally the lower your resting heart rate. This is due to the heart getting bigger and stronger with exercise, and getting more efficient at pumping blood around the body.
However, your heart does not beat with a steady rhythm. The intervals vary from one heartbeat to the next. And this is where HRV comes in. Put simply, it measures the variation in the time interval between heartbeats.
Its all linked to your sympathetic and parasympathetic nervous system. These are parts of your nervous system that control your body’s survival functions such as breathing, heart rate, digestion, organ control and blood pressure.
The sympathetic part of the nervous system is linked to the fight or flight instinct. It fuels your body into action when needed. The parasympathetic part is the counterpart. It helps your body to rest and recover when shocked by the sympathetic nervous system. HRV is a way to analyze and observe the parasympathetic nervous system. Unlike your resting heart rate, you should be aiming for a high HRV. Its a bit counter-intuitive, but a healthy HRV should not be beating t a perfect tempo. Research has shown that when your HRV is high, your body is showing better stress resilience and health. Which means, the more variability between heartbeats, the better. Typically, a higher HRV is correlated with younger biological age and better aerobic fitness.
A low HRV (little variation between beats), on the other hand, indicates less resilience. You’ll get low values when you are overloaded with stress, are sick, have not slept well or have been working out a bit too much. This is when its good to take some time to recover. Recovery makes performance possible.
A few low values should not be of concern as your HRV will vary from day to day. But if your HRV is consistently low it could be an indicator of health problems. Best to consult a doctor if this is the case.