For people who aren't super fit to start with, different types of workouts—like steady cardio, intense interval training, and short sprints—boost the energy powerhouses in their muscles by about the same amount, around 23–27%.

Sprint workouts might boost your muscle energy factories way faster per minute than other types of exercise — about 2-4 times more efficiently than harder or longer workouts, especially if you're just starting out or somewhat active.

Doing steady, moderate exercise regularly might help your muscle cells' energy factories work better by boosting a protein that helps them merge and stay healthy.

Doing light, steady exercise—like a brisk walk—can boost the energy powerhouses in your muscles.

Doing moderate, steady exercise like brisk walking or cycling for several weeks might boost the energy powerhouses in your leg muscles, which could help your body burn fuel better and improve overall health.

When young adults do intense workout bursts, take a 3-month break, then start again, their muscles' energy factories improve more the second time—even if their overall fitness doesn’t get much better—like their cells remember how to adapt faster.