Here are some exercise tips from Dr. Ratey:

1. Commit to six hours a week: do some form of aerobic exercise six days a week, for 45 minutes to an hour. Four days should be on the longer side, at moderate intensity, and two on the shorter side, at high intensity, but don't do it back to back; your body and brain need to rest.
2. Types of exercise include low-intensity (walking); moderate (jogging); high (running).
3. Start your exercise regime by walking, with a goal of 10,000 steps a day (about five miles). Once you work up to an hour of walking (without feeling too winded to be able to converse with a walking partner), increase your pace to moderate and then to high-intensity. (Details on how to differentiate between the different intensities can be found in the book).
4. If you only have 20 minutes to exercise, do a moderate work-out with intervals of sprints.

Dr. Ratey explains that if you miss a few days or even a week or so, your brain will respond again quickly- as soon as the second day back on track. He also recommends exercising in the morning, though evening workouts are equally good.

Whatever time or type of exercise you choose, there's one main thing to remember. As the commercial so aptly expresses it, "just do it."

*Note: always check with your physician before beginning an exercise program