You know that logging miles on the treadmill can give you a trim body, but adding more cardio to your life will also ratchet up your smarts, boost your productivity, rev your energy, and turn you into an unstoppable success machine. Even one 30-minute cardio session pumps extra blood to your brain, delivering the oxygen and nutrients it needs to perform at max efficiency. Cardio also floods the brain with chemicals that enhance functions such as memory, problem solving, and decision making. And new research has found that this kind of exercise may even cause permanent structural changes to the brain itself.
"Cardiovascular health is more important than any other single factor in preserving and improving learning and memory," says Thomas Crook, Ph.D., a clinical psychologist and memory researcher. "You're working out your brain at the same time as your heart."
And the mental mojo you get from cardio isn't limited to making you smarter. It also has the power to lower your stress levels and shake you out of a funk. It's no coincidence that so many high-achieving women—from Madonna to Condoleezza Rice—share the cardio habit. Here's how it works.
Your Brain on Cardio
Anyone who has ever tackled a StairMaster has a pretty good idea of what happens to your body when you break a sweat. But here's what's going on in your head at the same time: All that extra blood bathes your brain cells in oxygen and glucose, which they need to function. The more they get, the better they perform.
Every muscle you move also sends hormones rushing to your brain. There, they mix with a chemical called brain-derived neurotrophic factor, or BDNF, which plays a role in brain cell growth, mood regulation, and learning. "BDNF is like fertilizer for the brain," says John J. Ratey, Ph.D., associate clinical professor of psychiatry at Harvard Medical School. "Without it, our brains can't take in new information or make new cells."
Exercise has another vital role: It signals the release of several key hormones, including serotonin, the famed mood booster; dopamine, which affects learning and attention; and norepinephrine, which influences attention, perception, motivation, and arousal. This exercise-induced chemical cocktail has a powerful impact. "By elevating neurotransmitters in the brain, it helps us focus, feel better, and release tension," Ratey says.
Experienced regularly, all that rushing of blood and hormones primes your brain to grow. In one study, researchers scanned the brains of people who exercised for one hour per day, three days a week, for a duration of six months. They discovered an increase in the size of the hippocampus, the part of the brain that controls memory and learning. Working out literally bulked up the study participants' brains, allowing them to perform better at tasks that require concentration and recall—two talents that come in handy if, say, you do your own taxes or tend to forget passwords. "Exercise improves attention, memory, accuracy, and how quickly you process information, all of which helps you make smarter decisions," says Charles H. Hillman, Ph.D., an associate professor of kinesiology and community health at the University of Illinois at Urbana-Champaign.
The Mental Advantage
People who exercised during their workday were 23 percent more productive on those days than they were when they didn't exercise, says a recent study from the International Journal of Workplace Health Management. And the majority of the study participants (72 percent) did aerobic workouts.
A pulse-pounding workout acts like a cup of coffee (minus the jitters): Your heartbeat picks up, your circulation increases, you're filled with energy, and your thinking becomes clearer and sharper. What's more, a study published in Brain and Cognition found that after just 30 minutes of doing an easy half-hour bike ride, subjects completed a cognitive test faster than they did before exercising...and just as accurately. And the brain-boosting effect lasted for at least 52 minutes after the ride.
Use this cardio-induced clarity to your advantage by timing your daily sweat sometime before you punch the clock, on your lunch break, or prior to a demanding task like a big meeting (just don't skip the post-workout shower!).
Boost Your Memory
If you suck at remembering names, lay off the sudoku and feed your brain some exercise. In a study published in Perceptual and Motor Skills, women performed 20 percent better on memory tests after running on a treadmill than they did before exercising. They also increased problem-solving abilities by 20 percent.
The intensity of your workout makes a difference too. A study in Neurobiology of Learning and Memory found that people learned vocabulary words 20 percent faster after intense exercise than after low-intensity activity. Those who did more-demanding exercise had a bigger spike in their brains' levels of BDNF, dopamine, and epinephrine afterward. So the more you challenge your body, the more your gray matter benefits.
Sweat More, Stress Less
The reason you feel better after taking a kickboxing class may have more to do with your mental state than how many punches you landed. According to a study presented last year at the American College of Sports Medicine's annual meeting, exercise can improve your outlook. After riding a stationary bike for 20 minutes at moderate intensity, a group of 18- to 25-year-olds reported an immediate positive change in mood. While the study didn't measure endorphins, it's known that your body can release the euphoria-inducing chemicals during exercise.
