When you push your muscles to their absolute limit with heavy lifting, your muscles quickly pull in more sugar and turn it into a form that helps them keep working hard — like revving up a battery to...

When you push your muscles to their absolute limit with heavy lifting, a specific chemical in your muscles more than doubles — this might help your body keep making energy without running out of steam.

When you lift super heavy weights until you can't do another rep, your muscles use up a lot of their stored sugar (glycogen) to keep going — this shows your body is breaking down that sugar fast to power your workout.

After a hard, short workout, your body releases more sugar and insulin into the blood, which helps your muscles refill their energy faster.

If endurance athletes eat a specific amount of carbs right after a workout—especially a mix of glucose and fructose—they’ll probably refill their muscle energy faster, especially if they’re not eating a lot of carbs overall and need to recover quickly for their next session.