As you watch your parents or your grandparents' generation age, you’ve probably noticed it yourself. Seniors who are physically active are generally just more mentally “with it” than those who are content to sit in the easy chair and let the contestants on American Ninja Warrior do all the work on TV.

In fact, study after study has shown that people who move more don’t just have healthier hearts and lungs (and maybe better definition in the calf muscles). They usually score better on tests that measure memory and decision-making as well. There’s a reason that people in the health world sometimes call exercise “food for the brain.”

It is true that this kind of research usually relies on people’s own estimation of how much physical activity they get, which can be unreliable. However, the results from one recent study should banish any uncertainty. Scientists strapped accelerometers, electronic devices that measure movement, to nearly 500 people and tracked them for twenty years, to see how much they moved corresponded to how well they did on cognitive tests they regularly took for the length of the study. The conclusion was inescapable: move more; think better!

So now researchers are on the threshold of figuring out the hard part: what’s going on inside your brain when your body is in motion. In other words, what explains these almost (but not) too good-to-be-true results. Here’s the take-away to date:

Your brain gets better “irrigated”.  

Think of your gray matter as your own inside-the-body garden. And just like a garden, it needs to be regularly watered, or else patches here and there will wither and even die off. So goes the brain. It needs healthy circulation in the small vessels inside of it to bring oxygen and nutrients throughout the organ. And nothing promotes healthy blood flow and tamps down the production of vessel-clogging plaque like moving the body.

Your brain gets bigger.

Let’s stick with the brain-as-garden idea. In a well-nourished garden, your plants sprout new leaves and shoots. Same with the brain. Exercise promotes something called “neurogenesis.” Put simply, you grow more new brain cells. Blood drawn from exercisers is likely to show a higher level of a particular chemical, BDNF, that promotes cell growth upstairs. And the more your brain is able to generate new cells, the better it can respond and adapt to the changing world around you. (Ever notice that some seniors seem to be stuck in a past decade. Don’t let that be you.) Scientists have a fancy term for this: neuroplasticity.

The very latest research has even shown that the brains of people who move more are actually, on average, physically bigger! They have a thicker cerebral cortex, where the brain does most of its cognitive heavy lifting. (The hippocampus region, essential for making and keeping memories, is especially important here.) When we’re younger, a physically bigger brain doesn’t necessarily mean a smarter brain. But, as we age, shrinking brain volume spells cognitive problems. So get moving – and keep moving!

Brain and body fight inflammation together.    

For all the direct effects that exercise has on brain health, the indirect ones, via the cardiovascular system, may be just as important. Moving the body eats up excess sugar in the bloodstream which not only keeps the heart healthy but keeps our muscle cells sensitive to insulin. We get more mileage with less insulin and that protects us from prediabetes and diabetes and ensures the whole body is running on an even keel (think, low-inflammation). That very much includes the brain. It’s now well established that people with cardiovascular and metabolic issues are at much higher risk for dementia and Alzheimer’s. For years, integrative doctors have thought of these neurological conditions as diseases caused by “inflamed brains.” And now brand-new research is suggesting that exercise may be tamping down brain inflammation directly by maintaining the health of the brain’s immune cells, the microglia.

A happy brain is a smart brain.  

I hope you‘ve noticed that when you’re getting more physical activity in your life, you usually just feel better, about everything. We know that exercise stimulates the production of a brew of brain chemicals that make us feel good, everything from endorphins to serotonin and dopamine. And new research suggests that it can actually increase the number of dopamine receptors in the brain, helping to keep us “receptive” to the fun things in life. (In other words, the answer to the “same old, same old” syndrome.) Movement also serves to keep our stress hormones in check. High levels of our primary stress hormone, cortisol, are closely associated with depression which is all too good at making your brain feel sluggish. We now know that exercise can be as or more effective than side-effect-laden anti-depression drugs in combating depression.

Grab Your Slice of the Brain Benefit Pie.  

OK, this one isn’t brain science (except that it is): move your body. The government recommends at least two hours a week of moderate-intensity aerobic exercise. Boring and dutiful-sounding, right? The antidote to that is to build movement into your everyday activities: take walks and climb stairs to get where you’re going; take a break at your desk and do some calisthenics or yoga poses; do anything other than sitting in one spot for prolonged periods of time. You may not consider these frequent mini breaks throughout the day a “work-out” but your body does. What’s more, your insulin metabolism will become more efficient and those brain-enhancing brain chemicals will begin to pump.

All that said, the research does suggest that some of the brain benefits of physical activity are enhanced when you move vigorously, working at higher heart-rate levels. That doesn’t mean you have to be down at the track doing sprint intervals like you’re training for the Olympics (but if that’s your thing, go for it). Try taking a daily long walk. Maybe you do half the walk at your normal comfortable soaking-in-the-scenery pace and the other half as briskly as you can, without breaking a sweat or into a jog. Like to swim? Alternate between sprints and laps done at a more relaxed pace. It all works, so don’t just stand there, move your body to support your brain!