It’s the morning after Thanksgiving, and you’re not feeling awesome: Too much pie combined with staying up late with your cousins the night before have you wishing you could lounge in bed all day. Plus, you’re stressed about that English paper due the day you get back from the holiday. The last thing you feel like doing is working out. But if you fight through that reluctance and move your body—even just by going for a walk around the block—you’ll not only feel physically better, you’ll get more energy, be in a happier mood, and even have improved focus and concentration for writing your paper. Can exercise really do all those things? It really can. Here’s how.