It's important to have an occasional day of rest when working out. However, don't make that break too long. New research has found that when we stop exercising, we not only lose muscle mass (no surprise there), we also lose brain strength.

The study, led by the University of Maryland's School of Public Health, found that physically fit, healthy older adults who stopped exercising for ten days (that's right, only ten days) showed signs of significant decreases in blood flow to parts of the brain�like the hippocampus�responsible for thinking, learning, and memory.

In this study, researchers used MRI brain scans to measure blood flow in older adults (50-89 years old) who were considered extremely fit (i.e., "master athletes"). The measurements were done before they stopped exercising, and again ten days later. The results showed significant reductions in resting brain blood flow in eight brain regions, including the right and left hippocampus. The other seven regions included parts of the brain structure also known to deteriorate quickly in people with Alzheimer's disease.

Because the participants were all master athletes, they shouldn't be considered equivalent to the typical active older adult. However, this research still adds to growing evidence that exercise improves cognitive health and positively impacts the hippocampus in older people. (In fact, additional research shows that exercise can actually prevent the hippocampus from shrinking.)

Bottom line: Exercise is good for your body, but it's also good for your brain. So if you don't want to lose it� move it.

This post originally appeared on Lifetime Daily.