Exercise!

Want to be sharper at work? Feel less tired at home? Spend some quality time with your spouse? How about enjoying a cookie without guilt? If you answered "yes" to all of these questions (and who wouldn't?), exercise is the answer.

This pictures illustrates 10 fitness facts that may help inspire you to get off the couch.

1. Exercise Boosts Brainpower

Not only does exercise improve your body, it helps your mental function, says certified trainer David Atkinson. "Exercise increases energy levels and increases serotonin in the brain, which leads to improved mental clarity," says Atkinson, director of program development for Cooper Ventures, a division of the Cooper Aerobics Center in Dallas.

All that makes for a more productive day. "It is clear that those who are active and who exercise are much more productive at work," says Todd A. Astorino, assistant professor of kinesiology at California State University-San Marcos. Improved productivity not only makes you a better worker, it makes things better for everyone in the workplace. Companies with less wasted work hours and less sick time end up with lower health-care costs -- and an improved bottom line, Astorino says.

2. Movement Melts Away Stress

As much as it may stress you out just to think about exercising, once you actually start working out, you'll experience less stress in every part of your life.

"Exercise produces a relaxation response that serves as a positive distraction," says Cedric Bryant, chief exercise physiologist for the American Council on Exercise. He says it also helps elevate your mood and keep depression at bay.

You're not the only person who will benefit from more happiness and less stress in your life. When you're less stressed, you're less irritable, Atkinson says -- and that could improve relationships with your partner, kids, and coworkers.

3. Exercise Gives You Energy

You might be surprised at how, say, popping in a workout DVD for 30 minutes in the morning can change your whole day. When endorphins are released into your bloodstream during exercise, says Astorino, "you feel much more energized the rest of the day."

And when you improve your strength and stamina, it's easier to accomplish everyday tasks like carrying groceries and climbing stairs.