This morning I came across a Fast Company article on NYU neuroscientist Wendy Suzuki and her book, Healthy Brain, Happy Life, a memoir-slash-scientific monograph about the relationship between exercise, brain health, and intelligence. Some of the findings— like the role exercise plays in helping people deal with stress— won’t be a surprise, but other parts are more novel:

One reason exercise leads to a happier, healthier brain is because it promotes neurogenesis, or the birth of new brain cells, which helps improve cognitive function, says Suzuki. Importantly, there’s one very specific region of the brain where actual new brain cells are created because of exercise: the hippocampus. A small seahorse-shaped region on either side of the brain, the hippocampus is critical for our ability to form and retain new long-term memories.

With only two areas of the brain capable of producing new brain cells in adulthood—the olfactory bulb, associated with our ability to smell, and the hippocampus, which is critical not just for memory, but also mood and imagination, says Suzuki, it’s important to understand just what’s going on neurologically when we exercise.

The hippocampal cells produced as a result of exercise aren’t the same as the ones we already have, she says. “They are different from the old hippocampal cells that are there,” says Suzuki. Because they are newer and stronger, “they get integrated into more hippocampal circuits faster.” Hence the improvement in memory and mood.

Much of the research in exercise and its effects on the brain has focused on the prefrontal cortex, the area of the brain involved in shifting attention, personality, and executive functions like decision making. While exercise doesn’t produce new brain cells in the prefrontal cortex, it does promote gliogenesis, or the production of support cells that connect neural cells in the prefrontal cortex, allowing them to work more efficiently.

During exercise, there’s a hormone secreted by the muscles called irisin, which stimulates the presence of BDNF, or brain-derived neurotrophic factor, important for the efficient transmission of signals in the brain. “BDNF, like the oil in a car, will grease the wheels and make the brain work better,” says Suzuki.

These benefits don’t all come quickly: it took a year and a half for Suzuki to see all the improvements in brain health— and greater attention, concentration, etc.— that she describes in the book.

I think one of the reasons I’ve been able to write two books in the last couple years, and generally feel smarter than ever, is that I now take exercise much more seriously than I did earlier in life. (One of the things that got me back in the gym and taking exercise seriously was John Ratey’s Spark: The Revolutionary New Science of Exercise and the Brain. I highly recommend it.) Not that I’m in amazing shape today, but you don’t have to look like a Pilates instructor to get the cognitive benefits of exercise. (And after years I’ve discovered that when I’m in better shape I don’t get svelte, but bulkier— the term “barrel-chested” was invented to describe how my body responds to exercise.) So I go to the gym regularly, and I try to avoid driving in favor of biking (having a job that’s only a couple miles away helps) and walking (having two dogs REALLY helps). 

It’s also led me to support both my kids being more athletic, on the theory that it would provide benefits both immediately and in the long run. I played a little soccer in high school, but didn’t really keep it up, and if I had to do high school over again, I’d continue playing. (There’s a very interesting study about the relationship between sports and lifetime earnings: people who play sports tend to have more lucrative careers than those who don’t.) Fortunately, the Bay Area has some outstanding coaches, and a climate that allows for sports year-round; and neither of my kids is in a school or a sport that attracts really hard-charging, win-at-all-costs coaches or parents.