When the Cleveland Browns' standout running back Trent Richardson hits the practice field for wind sprints this summer, the wry smile on his face won't just be because he's confident of improving on his most-touchdowns-by-a-rookie season. Kicking out over a gallon of sweat during practice (no problem in summer camp) is guaranteed to raise your spirits, as long as you stay hydrated.
 

For those of you who enjoy your workouts at a slightly slower pace, three to five sessions of exercise for 45-60 minutes can up your happy quotient ... and your sagging backside! The routine: Aerobics that raise your heart rate to 80 percent to 85 percent of its maximum (max heart rate is equal to 220 minus your age) and resistance training (three sets of eight repetitions) at 80 percent of the max you can lift.

A bit depressed? Doing this routine for 10 to 12 weeks will give you a much more upbeat outlook.
 

What happens to the body when you sweat? All kinds of magic. Your 2.5 million sweat glands keep you cool and clean out your pores for healthier, smoother skin. Internally, you're promoting blood vessel flexibility, ridding your body of toxins and cranking up endorphin and serotonin levels - that'll raise your mood!

You're also creating brain connections and neurons, and fending off cognitive problems by making your key memory area, the hippocampus, bigger. And, oh yeah, if you're physically active, you'll have a more active sex life, too! So, head outside for some sweet sweatin' - and drink 8-16 ounces of non-sugary liquid for every 60 minutes of exercise.