Eli5 Heart rate variability


Eli5 What is heart rate variability and why is it important??

In: Biology

Your heart never really beats at a steady rate, instead it varies from moment to moment based on need. You can use this to determine some things about a person’s health and mental state.

For a person living relatively normally without a lot of stressors, getting into a situation that is stressful or anxiety inducing will cause abrupt shifts in heart rate.

But someone under a lot of stress for a long time will have a much slower change in rate in similar situations. They’ve gotten ‘used’ to it to the point where their body only just barely cares.

So a higher variability means you are in general in better health. Of course this alone doesn’t tell you very much, so you need more data from other systems to really tell you how someone’s doing. And it also really only matters when measured long term, just because of natural variation that happens from daily events which otherwise have no impact.

So its a useful tool, but not a clear indicator of much on its own.

Just to make things clearer. Heart rate variability is not really a change in heart rate in longer scales. Your heart rate can be 60bpm and stay there for several hours when you are sleeping for example. but there is variability between each heart beat. 60bpm heart rate means that heart beats every 1s on avarage during the time of doing that measuremets but the actual heart beats differ from each other (differences can be like 100ms for healthy persons)

changes in this variability can explain stress/exhaustion/diseases and so on because the variability is important for heart to quickly adapt to different physiological changes. The reasons behind this complex variability are not easy but it has been shown that stress and overtraining can reduce the variability so measuring it can be used to detect stress/overtraining for example.