Are you nervous? Many people do yoga to increase strength and flexibility, to lower stress and to gain mental and spiritual clarity. Those are great reasons. After a yoga practice, no matter which style (e.g., Ashtanga, Iyengar, etc.) you'll undoubtedly be left with an overall feeling of peacefulness that tops the way you felt before you moved your body.

Getting physical does make you feel good, as the endorphins released during bodily activities directly influence your mental health. Try spending a day in front of your computer, typing away furiously—using the excuse that you have no time for exercise due to a client deadline.

"It happens whenever you look at me," he says of my morning look.