How fast does that heart beat?

Heart rate falls with body size almost perfectly — a shrew’s heart runs 200 times faster than a blue whale’s.

Heart rate Measured in

Almost exactly a human at rest

70 bpm is faster than 3 of the 10 references on this page.

Reference figures are measurements and are rounded; the unit conversion behind them is exact.

Every reference on this page, with its size and its ratio to your number
Reference	Size	Yours ÷ theirs	Note
blue whale	6 bpm	11.7×	As low as 2 during a dive
elephant	28 bpm	2.5×
horse	40 bpm	1.75×
human at rest	70 bpm	1×
dog	110 bpm	0.636×
human at exercise	160 bpm	0.438×
cat	160 bpm	0.438×
mouse	600 bpm	0.117×
etruscan shrew	1,200 bpm	1/17.1	The smallest mammal
hummingbird in flight	1,260 bpm	1/18

A blue whale’s heart beats twice a minute at the bottom of a dive and about 37 times at the surface.
An Etruscan shrew’s heart beats 1 200 times a minute — 20 times a second — and it must eat twice its body weight daily.

Frequently asked

Because surface area grows more slowly than volume, so small animals lose heat faster per gram and must burn energy faster to replace it.

60 to 100 beats a minute for an adult. Endurance athletes are routinely in the 40s, and below 40 is common in elite cyclists.