Lifting heavy weights just a few times doesn’t stress your body as much right after as doing lots of lighter reps.

Doing many reps triggers a bigger stress and inflammation response in the body right after exercise than doing fewer heavy reps.

When trained guys do lots of reps, they feel more tired, weaker longer, and more stressed than when they do fewer heavy reps — even though their muscles are damaged about the same.

More reps don’t break your muscles more than heavy lifts — but they do make you more stressed and tired right after.

Even if you lift heavy or light weights for 12 weeks, your body’s short-term hormone spike after each workout doesn’t change—and that means those hormone surges probably aren’t why your muscles get bigger or stronger over time.

When you lift weights that get harder or easier as you move (like with resistance bands), your body reacts more strongly in the short term—your muscles get more tired, your stress hormones spike higher, and your cells show more signs of being worked hard—compared to lifting the same weight the whole time, even after training for 20 weeks.