Heart rate variability,explained

HLTH Science  ·  4 min read

A healthy heart doesn’t tick like a clock. The time between beats shifts slightly from one beat to the next, and that variation, called HRV, reflects how your body is coping and recovering.

What is HRV?

HRV is the natural, millisecond-level variation in time between heartbeats [1]. HLTH Band tracks it overnight, when your body is still and readings are most comparable night to night.

Your two-speed nervous system

Your autonomic nervous system has two sides: “rest and digest”, which tends to raise HRV, and “fight or flight”, which tends to lower it [1][2]. HRV is one window into the balance between the two.

What higher or lower HRV means

As a rough guide, higher HRV is linked to a relaxed, recovered state, and lower HRV to stress, poor sleep or hard training [1][3]. But HRV is very personal. Compare yourself with your own baseline, not with anyone else.

What moves your HRV

Habits that support your HRV

Keep regular sleep times, go easy on alcohol, build in rest days and find ways to unwind. Then watch your overnight trend over weeks rather than reacting to one night.

How HLTH Band tracks HRV

The band’s optical sensor reads the timing of your pulse while you sleep, and the app charts your overnight HRV as a trend. Daily ups and downs are normal; the longer trend is what’s useful. Use it to help decide whether to push or rest.

HRV questions

What’s a good HRV?

There’s no single good number. It’s personal [1].

Why does mine change every day?

Sleep, stress, alcohol and training all move it.

When does the band track it?

Overnight.

Can HRV tell me if I’m ill?

No. It’s a wellness trend, not a medical test.