Q. I heard regular aerobic exercise is better for the brain than strength exercises (resistance training). Is that true?
A. The study you probably heard about involved rats, not humans. The rats were made to engage each day in sustained aerobic exercise, high-intensity interval training, or resistance training, or they were allowed to just be sedentary. At the end of the study, the researchers examined the rats' brains. The rats doing regular aerobic exercise had more brain cells than the sedentary rats. However, the rats made to perform high-intensity interval training or the ones doing resistance training did not have more brain cells than the sedentary rats.
Why was this study done in rats, not people? Rats are mammals, like us, with brains built like ours. They don't live long, so you can study them for a good fraction of their life span, in a relatively short fraction of yours. And, at the end of the study, you can take out their brains and count the number of brain cells. It's not so easy to get similar information from human volunteers.
We don't know if this study has lessons for humans. I'm betting it does.
-- Anthony Komaroff, MD
Editor in Chief, Harvard Health Letter