Everyone knows that exercise gets our blood pumping, burns fat and calories, and reduces the chances of developing heart disease and obesity, among other maladies. But now a growing body of evidence suggests that even as few as 10 minutes of activity a day can bolster your mental health and leave you thinking more clearly and feeling happier and less stressed. People who exercise report feeling better in general -- even after just one workout. Here, five ways that exercise revs up your state of mind.

1. Exercise boosts brain power.
"We know that regular physical activity improves reaction time, concentration, creativity and mental vigor, Most likely, that's because it improves the body's ability to pump blood, which boosts the amount of oxygen in the bloodstream and speeds up blood flow to the brain. Experts believe that all of these changes encourage quicker physical and mental reactions.

2. Exercise helps fight aging.
In a recent study, researchers found that doing something as simple as walking on a regular basis helps prevent mental slowdown in women over 65, and the longer and more often they walk, the greater the mental edge. Best of all: Most people reap these stay-sharp benefits after just nine weeks of thrice-weekly workouts. The sessions don't have to be high intensity, It's enough to just move around and get your heart rate up.

3. Exercise stops stress in its tracks.
Exercise can reduce anxiety and may even help you deal with anger. The reason is simple: It's tough to focus on unpaid bills and looming work deadlines when you're running your heart out on the treadmill. Aside from helping you forget about that mile-long to-do list, regular aerobic exercise also boosts your cardiovascular fitness, which may actually make you less likely to overreact to problems and able to recover more quickly from major life stressors. Rhythmic, repetitive aerobic activities, such as walking, cycling, swimming and jogging, are best for busting stress, as are more obviously meditative pursuits, such as yoga.

4. Exercise gives you a natural high.
Whether you prefer your workouts short and intense or long and leisurely, exercise can boost levels of feel-good chemicals in the brain, such as adrenaline, serotonin, dopamine and endorphins, the body's natural painkillers. (How else could a marathoner run 26.2 miles and have fun doing it?) A study conducted in England found that 83% of people with mental health problems relied on exercise to improve their mood and reduce anxiety. For people with mild or moderate depression, we now know that exercising over a period of at least 16 weeks can have the same mood-boosting effects as prescription antidepressants such as Zoloft and Prozac.

Researchers found that 60% of people suffering from depression for four months who worked out for 30 minutes three times a week were able to overcome the blues without using any medication. One possible reason for the activity-induced boost: Exercisers seem to spend less time in the REM phase of sleep, a period during which the body stops producing serotonin, the depression-fighting brain chemical. But whatever the physiological reason, exercise is definitely a powerful drug. "This doesn't mean people should just stop taking their medication, especially if they have severe depression. But many psychologists are now writing a prescription for three weekly dates at the gym, along with the latest blues-busting medication.

5. Exercise boosts self-esteem.
It stands to reason that getting stronger, leaner and more adept at an activity can have a positive impact on self-esteem. Indeed, one recent study found that teenagers who are active in sports have a greater sense of well-being than their sedentary peers. There's a fine line, though, between committing to regular workouts and obsessing about getting to the gym. "The stress should be on achieving a healthy body image" and improving your fitness level, not on looking like some scrawny model on the cover of a fashion magazine.