Thump-Thump. Thump . . . Thump. (Thump.)

Pro athletes and coaches are using new technology to optimize training according to signals from your heart. Michael easter investigates whether you should, too.

- Jamie Millar

The human heart beats like a metronome, right? All evenly spaced thumps and regular rhythms? Wrong. When you’re at your healthiest, your heart is actually more like your six-Scotches-deep uncle whaling on the family drum set: The . . . ... beats . . . are spaced...... . . . . . . . . . ……… unevenly.

It’s only when your body is stressed— either for a short-term reason (like a bad night of sleep, a cold, or an insane deadline) or a long-term one (like you’re a smoker or have a chronically stressful job)—that the beats are more sober and steady. (We know: We were surprised, too.)