According to the Harvard Medical School, exercise:

  • Preserves muscle strength
  • Keeps your heart strong
  • Helps you maintain a healthy body weight
  • Staves off chronic diseases such as diabetes
  • Boosts your thinking skills

“Exercise boosts your memory and thinking skills both directly and indirectly, acting directly on the body stimulating physiological changes such as reductions in insulin resistance and inflammation, along with encouraging production of growth factors — chemicals that affect the growth of new blood vessels in the brain, and even the abundance, survival, and overall health of new brain cells," says Dr. Scott McGinnis, an instructor in neurology at Harvard Medical School. 

Studies suggest parts of the brain that control thinking and memory are larger in volume in people who exercise. Exercise can also boost memory and thinking indirectly by improving mood and sleep, and by reducing stress and anxiety.

Establish exercise as a habit, and be patient to start reaping the benefits. Studies have shown that it takes about six months to notice the cognitive benefits of exercise.

Aim for a goal of exercising at a moderate intensity — such as brisk walking — for 150 minutes per week. Start with a few minutes a day, and increase the amount by five or 10 minutes every week until you reach your goal.

Source: http://www.health.harvard.edu