Regular exercise is beneficial in the prevention of cognitive impairment and dementia in old age, according to the Alzheimer’s Association.

It’s considered to be a prime factor in reducing your risk of Alzheimer’s disease and especially vascular dementia because movement benefits brain cells by increasing blood and oxygen flow to the brain.

“There’s a lot of science behind this,” says Dr. Scott McGinnis, an instructor in neurology at Harvard Medical School.

Experts point out the exercise boost your memory and thinking skills both directly and indirectly. It stimulates physiological changes in the body such as reducing insulin resistance and dangerous inflammation. It also encourages positive growth factors such as producing chemicals that affect the growth of new blood vessels in the brain and improve the abundance and survival of new brain cells.

But exercise can actually affect the brain itself. Many studies have demonstrated that the parts of the brain that control thinking and memory are larger in people who exercise than in those who don’t, according to Harvard Health Publishing.

“Even more exciting is the finding that engaging in a regular exercise program of moderate intensity over six months or a year is associated with an increase in the volume of selected brain regions,” says Dr. McGinnis.

Exercise can also boost memory and thinking indirectly by improving mood and sleep, and by reducing stress and anxiety. Problems in these areas frequently contribute to cognitive impairment.

Although almost all of the research has been done on walking as the most common and available form of exercise, McGinnis believes any form of aerobic exercise—swimming, walking or biking- that gets your heart pumping could yield similar benefits.

Interestingly, a study published in the Journal of the American Geriatrics Society found that the gentle but disciplined art of tai chi also enhanced the cognitive function of adults. Those who participated regularly in this slow, focused form of martial arts gained benefits in the realm of executive function, which manages cognitive skills such as planning, working memory, attention and problem solving. Experts say learning and memorizing new movement patterns boosts brain power.

Dr. McGinnis recommends making exercise a daily habit, like taking prescription medication. And since most studies show it takes six months to start reaping the cognitive benefits, he prescribes a side dose of patience as you anticipate the results. And then he suggests making exercise a lifelong habit.

Experts recommend aiming for a goal of 150 minutes per week of moderate intensity exercise such as brisk walking. Start with a few minutes each day and increase the amount of time by 5 or 10 minutes every week until you reach your goal.