There’s no question that exercise is good for your body. But what does revving up your heart rate do for your brain?

“There’s a massive amount of scientific evidence that indicates that ongoing exercise directly does good things to your brain,” said Mayo Clinic Neurologist Dr. Erik Ahlskog. “It’s like liberating fertilizer in your lawn.”

Ahlskog said the brain shrinks with age, and it happens to nearly everyone and, “If you’re in your 80s, most people — maybe not all — but most people have kind of a shrunken brain,” said Dr. Ahlskog. “And if you look at it under the microscope at what’s going on, they’ve also lost a lot of brain connections. And it’s less losing brain cells than losing those connections. So, what can you do to maintain brain integrity? Well, it’s exercise.”

Dr. Ahlskog said any exercise that gets the heart pumping and makes people sweaty and tired works. He urges people to talk to their health care provider before beginning a new exercise program.