Why Exercise Is Good for Your Brain
Jan. 7, 2019 Psychology Today
As JPM Healthcare week kicks off in San Francisco, the conversation around healthcare turns clairvoyant as experts weigh in on their predictions for the big trends in the coming year. One of the main topics: Will this be the year we finally see a successful drug for Alzheimer’s disease?
But rather than play a guessing game, why don’t we look at what we know actually prevents dementia—improving your lifestyle. This article is the first in a five-part series focused on evidence-based methods to prevent dementia through lifestyle. Let’s begin with exercise.
Healthy Body, Healthy Mind
The Federal Government first published the Physical Activity Guidelines for Americans1 in 2008. Using science-based advice, these guidelines provide an overview of how much exercise Americans should perform each week (i.e., at least two days of muscle strengthening activity combined with at least 150 minutes of moderate-intensity exercise or 75 minutes of vigorous-intensity exercise). These guidelines address both healthy individuals and those at increased risk of chronic disease, stressing how exercise can prevent the effects of certain chronic diseases, including dementia.
An updated edition of the Physical Activity Guidelines was released in late-2018. The primary update was a section dedicated to the relationship between physical activity and brain health. This section explains the benefits of exercise for cognition, sleep, depression, anxiety, and overall quality of life. The government’s recognition of brain health finally publicizes its integral role in overall health and highlights how exercise benefits not just your body, but also your mind.
How Exercise Improves Brain Health
There are many ways exercise improves cognitive health. Aerobic exercise (also known as cardio) raises your heart rate and increases blood flow to your brain. Your increased heart rate is accompanied by harder and faster breathing depending on the intensity of your workout. As your increased breathing pumps more oxygen into your bloodstream, more oxygen is delivered to your brain. This leads to neurogenesis—or the production of neurons—in certain parts of your brain that control memory and thinking. Neurogenesis increases brain volume, and this cognitive reserve is believed to help buffer against the effects of dementia.
Another factor mediating the link between cognition and exercise is neurotrophins, which are proteins that aid neuron survival and function. It has been noted that exercise promotes the production of neurotrophins, leading to greater brain plasticity, and therefore, better memory and learning. In addition to neurotrophins, exercise also results in an increase in neurotransmitters in the brain, specifically serotonin and norepinephrine, which boost information processing and mood.
Exercise’s Lasting Effects on Cognition
In 2017, the Lancet released its landmark research commission on dementia prevention, intervention, and care that demonstrated that 35 percent of risk factors for developing dementia can be attributed to modifiable lifestyle traits. A significant component: exercise.
In a longitudinal study conducted by Dr. Zhu from the University of Minnesota, exercise tests were administered to a group of participants to determine their fitness levels. Those who were the most active in 1985 tended to still be on the fit side of the spectrum decades later. That same “fit” cohort also performed better on cognitive tests decades later.
Furthermore, exercise gives hope to people with a rare genetic mutation that programs them for early-onset Alzheimer’s disease. Although exercise cannot completely counteract their genetic predisposition, people who exercised for at least 150 minutes per week had better cognitive outcomes compared to those who did not.
Incredibly, exercise could potentially delay their dementia onset by up to 15 years.
Does Workout Type Matter?
Both the type of workout and method of staying fit are important to whether or not you experience cognitive benefits. It’s not enough to just count calories to stay thin, you still need to exercise. In fact, there is a term in medicine for people who are not healthy overall but manage to stay thin: TOFI (Thin Outside Fat Inside). Rather than exhibiting fat externally and appearing overweight, these individuals carry weight viscerally, around their internal organs. This is harmful to overall health—including brain health.
Between three sets of people—individuals who lost weight through restrictive eating, people who lost weight through exercise, and a group that used a combination of the two—only the groups who had exercise as part of their weight loss regimen noted an improvement in cognition.
It’s most important to concentrate on the type of exercise you perform if your goal is to maximize your cognitive health. A multi-component routine focused on balance, flexibility, and aerobic fitness is better than focusing on just one type of exercise. For example, tai chi has been heralded as an example of an all-encompassing exercise routine that significantly enhances cognition. A meta-analysis of research on tai chi and cognition found tai chi exhibited a greater effect on cognitive function than other types of exercise.
However, any exercise is better for your brain than none at all.
So, pick your exercise of choice! Go walking, running, swimming, hiking, or biking. Enjoy the fresh air. Get in touch with nature. And reap the many health benefits of exercise—both physical and mental.