There's a HUGE connection between the two. When you feel energized and strong, do you get sad? Nope. You get happy. When you see a picture and you like it, do you get sad? Nope. You get happy. When you can take the stairs and not the elevator, do you get sad? Nope. You get happy (and probably a little more winded than using the elevator). But when you look and feel better physically, a lot of times you feel better mentally.