John Ratey is a famous Harvard psychiatrist who wrote Driven to Distraction. In Spark: The Revolutionary New Science of Exercise and the Brain (http://www.amazon.com/Spark-Revolutionary-Science-Exercise-B...), he explains how intense aerobic exercise, like sprints or interval training, will generate the fuel that grows your brain and makes you smarter, and puts your brain chemicals in balance to improve learning esp if you have a history of partying, stress, anxiety, etc.

I have been running several miles a day for a few months, and then last week I started running sprints and noticed an immediate effect.

This is the routine I've been doing: I've been running in a field about the size of a soccer field. To start off I jog half the soccer field and then on the second lap I sprint the length of the field (about 50 yards) and then jog the remaining part. Then walk a lap to catch my breath. So one interval is three laps -- one jog, one jog/sprint, one walk -- at first I did that 4 times, and then increased it to 5, 6, 7, as you get better. When you sprint, just pump your arms and run as fast as you can. Do that 3 times a week -- every other day to let your brain and body recover. On off days, jog a few miles. He gives more details in the book.

I used to struggle to jog a mile at a slow pace, now I'm training for a marathon.

However, the mental benefits are key. So the reframing matters to me. If the purpose of cardiovascular exercise was just to run a marathon, it'd be a waste.