Does my heart rate variability (HRV) tell me anything about my health?

HRV measures how much the time between successive heartbeats varies. That variation is not noise: it reflects how flexibly your autonomic nervous system operates, the part that unconsciously regulates your heart rate, breathing and digestion. A higher HRV is associated with greater adaptability to stress and better overall health. But it remains a signal, not a direct cause: you cannot simply draw causal conclusions from it^1,2.

How clinically useful HRV can be is illustrated by a study of 271 hospitalised COVID-19 patients. In patients aged 70 and older, a higher HRV at admission was associated with a greater chance of survival and a lower chance of intensive care admission in the first week. In younger patients this association was absent. This is observational research, so causality has not been proven. But it shows that HRV can provide useful additional information for vulnerable older patients².

If you want to influence your own HRV, slow breathing is the best-supported approach. A meta-analysis of 223 studies shows that it raises HRV, both during and immediately after a breathing session and after a longer series of sessions. It costs nothing, requires no equipment and has few side effects³.

HRV biofeedback, in which you learn to consciously steer your heart rhythm with the help of a device, also has a broad evidence base. A meta-analysis of 58 randomised studies shows small to moderate positive effects on anxiety, depression, anger and athletic performance. For sleep and quality of life the effects are smaller. Researchers therefore view it as a complement to existing care, not a replacement⁴. A smaller study of 76 people compared five weeks of HRV biofeedback, mindfulness meditation and physical exercise: all three reduced stress, anxiety and sleep problems, with no clear difference between them⁵.

Music as a way to raise HRV has also been studied. Different genres can activate or calm the nervous system, but the effects are inconsistent and depend strongly on the type of music. The quality of the available studies is too low to recommend music as a serious intervention. For the time being, people looking to improve their HRV have little to gain from it⁶.