2 Hours a Week of Exercise Can Boost Brain Health

June 21, 2018

Exercising for at least 52 hours over a six month period — for an average of about two hours a week — can lead to improved thinking skills in older men and women, including those who already have dementia, a new analysis found. The exercise need not be intense and can include some combination of mild aerobics, like walking, strength training, or mind-body exercises, like yoga or Tai Chi.

The analysis, published in the journal Neurology, sought to determine how much exercise is needed to boost brain health. It identified 98 rigorous trials that focused on how much people exercised. Researchers collected information on how long people exercised for, how many times a week they exercised, and how much exercise they got over time.

The analysis included a total of more than 11,000 participants whose average age was 73. Of those, 59 percent had normal memory and thinking skills. Another 15 percent had Alzheimer’s disease or other forms of dementia. And 26 percent had mild cognitive impairment, a type of malfunctioning of the brain that half the time leads to full-blown Alzheimer’s disease.

Aerobic exercise was the most common form of exercise for study participants, with walking the most common activity. Biking and dancing were also popular aerobic forms of exercise. Others did strength, or resistance, training, the kind involving weights. And some did mind-body exercises like yoga or Tai chi.

The researchers found that at least 52 hours of exercise conducted over an average of about six months led to improvements in the brain’s processing speed, or the amount of time it takes to complete a mental task. Benefits were noted both in those who were cognitively healthy and in those with dementia or mild cognitive impairment. In healthy people, that same amount of exercise also improved executive function, or the ability to manage time, pay attention and achieve goals.

In contrast, people who exercised for an average of 34 hours (or less?) over the same time period did not show any improvement in their thinking skills.

“These results suggest that a longer-term exercise program may be necessary to gain the benefits in thinking skills,” said study author Joyce Gomes-Osman, of the University of Miami Miller School of Medicine in Florida. “We were excited to see that even people who participated in lower intensity exercise programs showed a benefit to their thinking skills. Not everyone has the endurance or motivation to start a moderately intense exercise program, but everyone can benefit even from a less intense plan.”

It is important to note that nearly 60 percent of those studied did not exercise before enrolling in a study. The findings suggest that combating sedentary behavior may be critical for good brain health. It is unclear from the current analysis whether similar cognitive effects can be seen in response to exercise in people who are already physically active.

While the analysis found that exercise improved thinking skills, it did show that exercise led to improved memory skills. But other studies in animal and people have found that regular exercise can lead to improvements in memory and may help to stave off dementia onset. The difference might be in the frequency and the intensity of the exercise.

The Department of Health and Human Services, the American Heart Association and the American College of Sports Medicine suggest that people engage in at least 150 minutes of moderate intensity exercise or 75 minutes of vigorous exercise per week to achieve benefits in physical health. And as numerous studies have shown, what’s good for the heart is also good for the brain.

Numerous studies have found that physical exercise can promote brain health, improving the ability to remember, learn, plan, concentrate, and maintain a clear, active mind. Exercise can also counteract many of the negative effects of aging, and may also help to combat major depression. When exercising in groups or at a gym, it brings a social component that is also beneficial. People who are very active and physically fit at midlife and beyond, for example, have a lower risk of developing Alzheimer’s disease and other forms of dementia in old age. This analysis found that even people who had symptoms of dementia could get gains from regular exercise.

By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Marc Flajolet, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.

Source: Joyce Gomes-Osman, PT, PhD, Danylo F. Cabral, Timothy P. Morris, et al: Exercise for cognitive brain health in aging A systematic review for an evaluation of dose. Neurology: Clinical Practice June 2018 vol. 8 no. 3, pages 257-265


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