High-intensity interval training (HIIT) and endurance training can stimulate the creation of new mitochondria (mitochondrial biogenesis).

“By the way, that's awesome. You want more mitochondria in your muscle. It's associated with improved muscle mass, improved endurance. Mitochondria are essentially, they're making energy in your cell. We don't make more mitochondria normally. You have certain inputs, high-intensity interval training, exercise can do it.”

“You have certain inputs, high-intensity interval training, exercise can do it. - Can actually make more mitochondria.”