Need to break out of a bad mood? Try these tips for cheering yourself up.

Think Fast
Rapid-fire thinking makes people feel happier and more energetic, confident and creative—even if they are thinking about something sad, reveals a study published in Psychological Science. "Slow thinking is a characteristic of depression," says researcher Emily Pronin, PhD, assistant professor of psychology at Princeton University, "and picking up the pace may cause mood-boosting chemical changes in the brain. It's like taking your mind for a run."

Stuck in a negative groove? Try this mental gymnastic: Quickly come up with five solutions to your problem—good, bad or in between, just do it fast. Other beneficial exercises: speed-read a magazine or just rapidly recite your pessimistic thoughts. Making your brain race may rev you up.

Shake a Leg
"Aerobic exercise is the single best way [to escape] a bad mood and increase your energy—and all it takes is ten minutes," says Robert E. Thayer, PhD, professor of psychology at California State University, Long Beach. "Sophisticated tests have shown that when you're feeling energetic, your good feelings about yourself are much stronger."

Act Extroverted
Feeling grumpy or gloomy? Then get out and act as if you're on top of the world! Being gregarious, assertive or adventurous can actually improve your mood—even if you're shy, finds a study from Wake Forest University in Winston-Salem, North Carolina.

"All the subjects, even introverts, reported being happier when they acted in an outgoing rather than a withdrawn manner," says study leader William Fleeson, PhD, associate professor of psychology. "This shows that changing your behavior can change your mood."

To see if acting like an extrovert can turn your frown around, smile at strangers, talk to neighbors, voice an opinion during a discussion or ask a question in a meeting at work, suggests Dr. Fleeson.

Give Yourself a Treat
When little annoyances darken your day, chase the cloud away with a little retail therapy.

"When you're feeling bad, treating yourself to something good does wonders for your spirits. It's a way of reminding yourself that you're worth the pampering," says Randy Larsen, PhD, professor and chair of psychology at Washington University in St. Louis.

Even the tiniest treat may pick up your mood, suggests research by Alice M. Isen, PhD, a psychology professor at Cornell University. "Good mood isn't determined by the size of the treat so much as the pleasure of the experience," says Dr. Isen, who found that something as simple as receiving a free store sample or finding money on the street put people in a more cheerful frame of mind.

Check In with a Cheery Friend
Moods are contagious. So being around someone with a sunny disposition or who makes you laugh may give you an attitude adjustment. But don't use a get-together for a gripe session. This will only reinforce your bad feeling—and drag your friend down.

Lend a Helping Hand
Random acts of kindness, such as giving money to a homeless person, bringing soup to a sick neighbor or making photocopies for a time-pressed co-worker, can make you feel happier, according to Stanford University study. Giving makes you feel good yourself, particularly when other people appreciate your efforts.