Heart Rate Variability

Heart rate variability (HRV) and its role in monitoring your health seems to be on everyone’s lips these days. I remember learning as a medical student that it is normal for our heart rate to vary when we breath. However, as with all medical research we are learning more about how important for our health HRV is.

This post will discuss HRV from a practical perspective:

  • what it is
  • what it can tell you about your body’s health
  • how to measure it
  • how knowing it can help you

 What is Heart Rate Variability?

A normal, healthy heart does not tick evenly like a metronome, but instead there is constant variation. We are not aware of this variation and most heart rate monitors we wear display your heart rate as beats per minute. Also, it is not the same as your heart rate increasing and decreasing with activity or rest.

HRV is influenced by exercise, hormonal reactions, metabolic processes, cognitive processes, stress and recovery. When learning to interpret ECGs we were taught about a phenomenon called sinus arrhythmia, where your heart rate slows when you breath out and increases as you inhale. This is just one component of heart rate variability.

What dies Heart Rate Variability tell you about your health?

 “Higher HRV has been found to be associated with reduced morbidity and mortality, and improved psychological well-being and quality of life.”

For a normal healthy person HRV should increase during relaxing activities such as sleeping and meditation. Whereas HRV naturally decreases during stress when your heart rate is higher. Stress can be exercise or being in a stressful situation. HRV therefore should vary from day to day, as our activity and mental stress fluctuates. However, when we are chronically stressed or overloaded HRV can remain low. The low HRV and raised stress hormone levels could lead to mental or physical health problems.

If you monitor HRV daily you can identify if you are in a period of chronic stress at work or home, or as an athlete if you are overtraining. This should alert you to the risk this could be having on your health. As an athlete you may need to have more rest or easy days. It is not always easy to manage work or family stresses, however this easy to measure metric could prompt you to take time for yourself.

How you can measure it yourself

There are ways you can measure it such as wearing a heart rate monitor chest strap or one of the many watch-like devices such as a Fitbit or Garmin. They will give you a number which is loosely described as your stress level. However not all wearable devices constantly monitor every heart beat.

There are apps available which use your camera on your smartphone. Some are free and tell you your HRV at that moment in time. Others charge, but give you much better insights into your health over time. I have used HRV4Training which requires daily use, but also allows you to input other data such as how you are feeling, alcohol consumption and any exercise you have done. It takes all this information and tells you whether you should rest or if you are ready for normal training or to reduce the intensity.

The ideal situation to get an idea of your day to day heart rate variability is to measure it the same time every morning before getting out of bed. This is when you should be at your most rested and your cortisol stress hormone at a consistent level.

How knowing your Heart Rate Variability can help you

You can improve their individual HRV by improving your health, fitness, stress management and recovery skills. High HRV is generally considered an indicator of a healthy heart. A higher HRV has been found in many studies to be associated with reduced morbidity and mortality and improved psychological well-being and quality of life.

You can monitor your HRV to:

  • assess your current health
  • use it to track any lifestyle changes you choose to make
  • watch for signs over overtraining before you become unwell