I'd recommend deep breathing exercises for stress reduction. It's easy, you can do it any place at any time, no equipment need and it's free.
Check out my webpage on breathing and there are exercises there. very easy!
www.Path2HealthyLiving.com/breathing.htmlIt's also good for asthma sufferers, increasing your metabolism and boosting your immune system. You'll feel like a million after doing the exercises for a couple weeks.