Glance around the gym, and you'll probably see lots of people who are exercising in an attempt to shed pounds, tone muscle and look better. But numerous research studies have uncovered many other benefits to working out, ones that aren't necessarily visible from the outside.

Here, some of the awesome ways exercise can benefit your mind, body and soul:

It zaps anxiety. Ever notice that you can start a workout feeling stressed and anxious, and end it feeling good? It isn't in your head. Or, actually, it is: According to a new study from Princeton University, exercise appears to change the chemistry of the brain by causing the release of GABA, a neurotransmitter that helps quiet brain activity and minimize anxiety. The study found that people who ran regularly had a low reaction to stressful situations, even if they hadn't run in more than 24 hours.

It boosts immunity. Regular exercise can reduce your risk of certain serious health conditions, including heart disease, diabetes and some cancers. It can also decrease your chances of developing -- and getting stuck with -- more common illnesses, such as flus and colds. (According to one recent study, colds lasted 43 percent longer for people who exercised once a week or less.)

It improves body image. After summarizing the effects of 57 separate studies, a group of researchers determined that exercise does indeed improve how you feel about your body.

It gets you in the mood. You may have heard that smelling the pheromones in sweat can make you want to get down and dirty -- but that's not the main reason exercise can lead to sex. For men, exercise can lower the risk of erectile dysfunction, and it gives both genders stamina and feel-good vibes about the body.