How Much Exercise Is Too Much for the Brain?

Hi. I'm Dr. Richard Isaacson, director of the Alzheimer's Prevention Clinic at Weill Cornell Medicine and NewYork-Presbyterian. What is the most optimal dose of exercise, when should it best be begun, and can someone do too much exercise when it comes to brain health and Alzheimer's prevention?

Some really exciting research has recently been published. One paper was written by collaborators from the University of Miami Miller School of Medicine, Beth Israel Deaconess Medical Center, and Harvard Medical School, who came together to do a very broad review of the literature.^[1] In that very nicely done paper, they showed that 52 hours was the optimal dose of exercise [associated with improved cognitive performance] over a 6-month period. Now, when you look at the numbers, that's about 2 hours of exercise per week. This included a mix of different [modes] of exercise, from aerobics to strength training, and a variety of different types.

In this study, exercise absolutely may have a positive impact on brain health. For the first time, we are starting to figure out a dose-related response. This is very interesting, but too much exercise may not be appropriate. Another study, called the DAPA trialwhich was conducted in the United Kingdom, was a randomized study that enrolled people who had mild-to-moderate dementia.