This Is Your Brain on Exercise
Hard workouts can improve mood, improve attention — and even build more gray matter.
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Science has spoken: It’s time to retire the “brains vs. brawn” trope. The stereotypical weakling genius and the ditzy gym bunny are as old and tired as blond jokes. And, according to recent research, they make even less sense.
A mountain of scientific findings has provided us with a new understanding of the human experience. Instead of acting as separate entities, or even working in opposition, the brain and the body are constantly communicating with and even nourishing each other. Exercise induces a cascade of benevolent changes within the brain, and when brains experience exercise on a regular basis over the years, they tend to age better.
The Game of Concentration
“Some evidence shows that people who have been physically active all their adult lives have less chance of developing depression, anxiety disorders or cognitive problems,” says J. Carson Smith, Ph.D., associate professor of kinesiology at the University of Maryland and the director of the Exercise for Brain Health Lab. Regular exercise can improve mood, increase resistance to stress and stave off age-related decline. And the improvements are not just related to transient surges in brain chemicals and hormones: Scientists have found that regular workouts actually build new supportive structures within the brain.
“There are many possibilities for how exercise may protect the brain from age-related disease,” Smith says. “What is so elegant about it and what makes it so difficult to study is that it affects everything all at once.”
The benefits that a hard workout imparts on your heart and your muscles are just as good for your brain, and for many of the same reasons. For instance, exercise helps control blood glucose and improve insulin sensitivity — two concepts familiar to fit-minded people because managing blood sugar leads to a leaner physique. But a study published last year in the journal Diabetologia found that subjects with chronic high blood sugar experienced cognitive decline at a faster rate than those with lower blood sugar. In other words, the higher the blood sugar, the faster the cognitive decline.
Another explanation for how exercise preserves cognition over decades is the possibility that exercise increases neurogenesis, new nerve cell growth in the brain. This theory hasn’t been proved in humans yet, since brains must be removed and measured from the test subjects to show the growth, but research strongly suggests that neurogenesis occurs in human brains.
“Exercise has been shown in animals to increase the number of nerve cells in the part of the brain called the hippocampus,” Smith explains. “The hippocampus is very important because it is part of our memory system. You have to have a healthy hippocampus to remember things. But the hippocampus also helps regulate our mood and our response to stress. So that might be part of what protects us, as well.”
Mood and Stress
Depression is a serious health epidemic in the United States, and according to the National Institute of Mental Health, more than 16 million Americans suffer at least one depressive episode a year, with twice as many women affected as men. Anxiety disorders also strike more than 30 percent of us at one time in our life. Throw in premenstrual syndrome, winter blahs and the prospect of the final season of Game of Thrones and these moments of despondency are understandable.
“Exercise has a very strong effect on improving mood, reducing anxiety and increasing feelings of relaxation,” Smith says. One study, published in the journal Psychosomatic Medicine, examined a group of depressed subjects and prescribed one of four treatment options: supervised exercise, home-based exercise, antidepressant medication or a placebo. After four months, the supervised exercise groups and the medication group had the highest (and nearly equal) rates of remission, followed by the home-based exercise group.
Theories abound about why exercise is such a mood booster. One common thought revolves around neurotransmitters — chemicals in the brain that respond to the environment and influence how we feel‚ specifically serotonin and norepinephrine. A deficiency in either neurotransmitter has been linked to symptoms of depression. Some of the most popular prescription antidepressants work by increasing the amount of serotonin and norepinephrine available in your brain. Not surprisingly, both serotonin and norepinephrine are released during exercise. Other hypotheses credit the postworkout calm to endorphins, increased core temperature, feelings of self-efficacy or just simple distraction from daily problems.
Smith points out that the effect of exercise on stress levels is the perfect example of the integral relationship between brain and body. Consider the classic Type A personality who may be a candidate for a stress-induced heart attack at age 50: Exercise reduces a major risk factor by mitigating stress while also strengthening the heart. A stronger cardiovascular system helps the brain become more resilient to stress. Everything works together.
So how exactly do you train your brain in the gym? Scientists have not determined a single training regimen that results in insane gray matter gains, but a few training factors stand out as particularly beneficial to your brain.
Cardio + Weights
Most of the research concerning exercise and brain function thus far has focused on cardio workouts, but a session in the weight room is just as effective, and a combination of the two creates a synergy that might be best of all, according to Smith.
“Resistance exercise is as effective as cardio, whether it is cognitive function or mood regulation,” he says. “In studies of cognition in older people, when you combine resistance exercise with cardiovascular exercise, you seem to get stronger effects.”
While you might dread it, your brain likes sprinting: Evidence shows that high-intensity cardio is where you see the biggest increases in neurogenesis, results Smith believes can be extrapolated to high-intensity interval training in the weight room.
“The manipulation of intensity using less time between sets
at a lighter load is an interesting question,” he says. “I don’t know of a study that has tested this, but my hunch is that it would behave like higher-intensity cardiovascular exercise and show decreased anxiety.”
Go Easy on the 1RMs
Research suggests that lifting very heavy weights actually makes your brain feel more stressed: A study out of Davidson College in North Carolina found that lifting less than 70 percent of your one-rep max produced the most reliable decreases in anxiety levels.
But don’t swap that barbell for a pair of pink rubber dumbbells just yet: Lifting heavy provides a slew of benefits from body composition to bone density. But if you’re training at the end of a very stressful day, try chasing a really good pump rather than a deadlift personal record.
Try New Things
Everyone knows that crossword puzzles and Sudoku help keep your brain pliable, but learning new exercises and movement patterns seems to do the same thing: A study published in the journal Nature Neuroscience showed that subjects who learned how to juggle experienced an increase in their white matter. White matter is made up of nerve fibers, so if gray matter is the computer, white matter is the cable that transmits messages to the computer, and impairment in white matter is a risk factor for Alzheimer’s disease. Adding movement-based workouts to your programming, such as yoga, Pilates or agility ladder drills, keeps your brain in the white.
The interaction between the brain and the body is a beautiful — albeit complicated — system of logic. Ultimately, what is best for your body is best for your brain: Work hard. Be consistent. Learn new things. Vary your workouts. Any exercise is better than no exercise. It’s a relief to know that at least something in this world was designed to make sense.
Regular exercise does more than keep your body fit and your mind stress-free, and the list of physiological functions that benefit from an active lifestyle never seems to end. Here are a few of the lesser-known benefits of exercise.
As we age, the outer layer of our skin gets thicker while the inner layer gets progressively thinner — resulting in that saggy look we all hate. A study out of McMaster University in Canada took skin samples from subjects’ buttocks and discovered that women 40 and older who exercised regularly had the opposite effect: a thicker inner layer and a thinner outer layer.
Good for Your Gut
Irish researchers found that professional rugby players had a greater diversity and more health-promoting strains of bacteria in their guts than sedentary men. A good thing because a loss of microbiome diversity is linked to a number of maladies. Scientists aren’t sure how much exercise is necessary to promote healthy bacteria, but being even moderately active helps.
One interesting finding of the Third National Health and Nutrition Examination Survey showed that adults who exercise regularly are less likely to have gum inflammation and disease.