why is heart rate variability a good thing?

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I’ve read that it indicates your heart’s ability to handle stressful stimuli, but I don’t understand why. Seems like you’d just want a steady heartbeat. Why isn’t high variation the same as arrhythmia?

ETA: a couple of articles I’ve read on the subject. They all say basically the same (no)thing.

https://www.health.harvard.edu/blog/heart-rate-variability-new-way-track-well-2017112212789

https://my.clevelandclinic.org/health/symptoms/21773-heart-rate-variability-hrv

https://en.m.wikipedia.org/wiki/Heart_rate_variability

In: Biology

3 Answers

Anonymous 0 Comments

I think in this case they’re not talking about how *steady* your heartbeat is, but the difference between your “resting” heart rate and your “stressed” heart rate. (It’d be nice to link the articles you just read, it makes it easier for people to understand what you’re asking about!)

When you’re stressed or exercising, you need your heart to beat faster so blood moves faster through your body and delivers oxygen/other things to the things that need it. But heart rates higher than some amount put stress on your heart and the rest of your circulatory system, so if your heart rate can’t go below that amount when you calm down you face increased risks of a lot of bad things.

So a healthy person has a relatively low “resting” heart rate. Obviously if it’s too low you could have a lot of problems, but in general if it’s lower that means less stress on your body, which is what you want when resting. People who have higher resting heart rates are having their circulatory system go through more stress than people with lower resting heart rates. You can sort of visualize your heart as having hit points like a video game, and more stress means it loses them faster. Less stress means it loses them more slowly.

Arrhythmia is a little different. Your heart’s normally supposed to respond to increased activity by beating faster, and gradually beat slower as you rest. In either case, if you maintain the same amount of activity, it ought to hit a pretty stable rate. You’d expect that to look like a curve, as it goes from say 70 to 80 to 100 to 120 as you get more active, then 125 to 120 to 100 to 80 to 70 as you calm down. Arrhythmia would look more like 70 to 90 to 50 to 120 to 70 to 140 to 110… you get the picture. It’s more of a jagged line than a curve. It might be because the heart isn’t even beating consistently. It’s supposed to be a nice rhythm: boom boom. boom boom. boom boom. But it could also screw up and be like boom…. boom. boomboom. boboom. boom…. boom. That messes up how well it can pump blood and is a very bad thing.

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