In guys who lift weights regularly, doing more reps with lighter weights and short breaks gives a bigger boost in growth hormone early on (by week 3) than doing fewer reps with heavier weights and longer breaks—but by week 10, that difference goes away.

If you lift lighter weights with only 30 seconds of rest between sets, your body might spike growth hormone and make your muscles look bigger right after the workout—more than if you lift heavier weights and rest for 3 minutes between sets, as long as the total amount of lifting is the same.

When men who lift weights start training, doing more reps with lighter weights causes a bigger short-term boost in certain hormones compared to lifting heavy weights for fewer reps. But this hormone boost gets smaller the longer they keep training.

If you're a guy who lifts weights, doing more reps with lighter weights (which spikes your hormones more) doesn't build more muscle or strength over 8 weeks than lifting heavier weights with fewer reps—even though the hormone changes look different.

Even though lifting weights with short breaks makes your body release more growth hormone, that doesn’t mean you’ll grow bigger muscles over time.

Even if your muscles get a big burst of growth hormone right after lifting weights, that doesn’t mean you’ll grow bigger muscles over time—some people who got way more of this hormone didn’t grow more muscle than others.