You already know you should exercise to improve overall health and prevent conditions like heart disease -- the No. 1 killer in the U.S. But that same workout you begrudgingly pushed yourself to do could also tone your mental faculties and help ward off cognitive decline that disproportionately afflicts older adults.
A recent research review of 36 randomized controlled trials featuring adults older than 50 finds that not only aerobic exercise, but resistance training -- like lifting weights -- can boost brain power in this age group. That held even for participants with mild cognitive impairment, like memory problems -- an important note given that, as researchers point out, previous research shows having MCI is associated with an increased risk of being diagnosed with Alzheimer's disease or dementia later.
The review "finds very positive evidence that undertaking a combination of aerobic and resistance training of at least moderate intensity is of benefit to the brain function of people over the age of 50," writes Joe Northey, PhD candidate at the University of Canberra Research Institute of Sport and Exercise in Australia, in an email. Northey led the review published last month in the British Journal of Sports Medicine.
While much research has focused on the effect aerobic activity has on the brain, the analysis -- shattering any meathead misconceptions -- also showed that resistance training could significantly boost executive function, which includes decision-making, as well as working memory, used to store bits of information for short periods to function through the day, and memory in general. "Although this does not show that resistance training is better than other modes of exercise, it does suggest that this type of training has particularly pronounced effects on these domains of cognitive function," the researchers wrote.
While the review stopped short of prescribing a particular exercise routine to boost brain power, research provides clues regarding how to maximize those benefits from working out. Here are a few expert tips:
Don't just dabble. The "dose" of exercise you get matters. While it's not been precisely determined what's optimal to maximize cognitive function, experts recommend following general physical activity guidelines. That means getting at least 150 minutes weekly of moderate intensity exercise, like brisk walking. Also, incorporate resistance training, such as light weights or squats with no weight, into your regular workout routine. "Undertaking just a few days of moderate intensity aerobic and resistance training during the week is a simple and effective way to improve the way your brain functions while also reducing the impact of other risk factors for cognitive decline such as obesity and diabetes," Northey says.
Push yourself -- within reason. Intensity matters. The analysis published in the Journal of Sports Medicine shows exercise intensity should be at least moderate to improve cognitive function. You should be able to maintain a conversation during moderate intensity exercise, while more vigorous intensity exercise will make it difficult to keep up a conversation and can usually only be sustained for up to 30 minutes, Northey says. If you don't have physical limitations, consider going for a run. And while focusing on repetition, increase the amount of weight used for resistance training.
Be mindful of the results. The more active you are, the more likely you'll realize the heady rewards. "Push yourself enough so that you can feel it and so that you can enjoy that endorphin high -- the mild euphoria people experience when they do engage in moderate exercise," says Dr. Gary Small, a professor of psychiatry and aging at the UCLA Semel Institute for Neuroscience and Human Behavior in Los Angeles. "I think that mood elevation is important to reinforce a behavior -- people like that feeling, and that makes them want to go back to the exercise, even though it takes some effort."
Even if you're not cruising on a runner's high, you may feel the results in other ways -- like being more mentally sharp after you've gotten back into an exercise routine. "We know from the physiology of what exercise is doing that in addition to the endorphin elevation that's beneficial, that our bodies produce BDNF: brain-derived neurotrophic factor, which is like fertilizer for the brain," Small says. "It stimulates the nerve cell connections to sprout branches, so that our brain cells communicate more effectively."
There's a lot going on to improve our brain function when we're active. "We also know that when we exercise, it increases the size of certain brain regions that are involved in thinking and memory; and a bigger brain is actually a better brain," he says.
Research shows that exercise can increase the volume of the hippocampus, for example. "The hippocampus is basically your main memory center of your brain," explains Teresa Liu-Ambrose, an associate professor of physical therapy at the University of British Columbia in Vancouver, and director of UBC's Aging, Mobility, and Cognitive Neuroscience Lab. In this way, "aerobic exercise can actually literally reverse your brain aging," she says. Liu-Ambrose was the senior author of a 2014 study, also published in the British Journal of Sports Medicine, that demonstrated this affect in older women with probable MCI. "Here we're seeing an actual increase in the amount of brain structures specifically within the hippocampus," and the study found that aerobic exercise seems to be an effective intervention to combat decline in cognitive function for people with MCI.
Think outside of the boxed-in workout routine. Tai chi could also help improve brain function, according to the recent analysis published in the British Journal of Sports Medicine. The number and size of studies looking at the effect of this noncompetitive martial art known for benefitting mind and body are still relatively small; so larger randomized controlled trials are needed to confirm those effects. But even so, it's a promising development, the researchers say -- particularly for people with more limited function, for whom exercises like tai chi are a good fit. This would also be expected to improve balance and flexibility which are important as you get older, Northey notes. Exercises that improve stability and balance have been shown to help reduce fall risk.
Besides brisk walking, cycling or tennis for moderate intensity exercise, he suggests doing things such as dancing or even gardening. While experts emphasize it's important to get your heart rate up (say, at the very least hoeing rows rather than sitting idly in the dirt for the garden variety workout), and to integrate your workouts into your regular routine, you needn't follow a rigid exercise regimen to benefit your brain.
Remember: It's all connected -- so exercise with brain and body in mind. In addition to its direct effect on the function and structure of the brain, exercise helps a person shed pounds and become heart healthier, and that's also good for your gourd. The wind in your lungs and the strength of your heart are critical, since high levels of oxygen and blood must be supplied to your brain for it to survive and thrive. "Anything that compromises that such as high blood pressure ... would compromise the health of your brain over time," Liu-Ambrose says.
That's one more reason not to put off working out. "By exercising, you're basically promoting better cardiovascular health, which is critical for brain health," she says.
Michael Schroeder is a health editor at U.S. News. He covers a wide array of topics ranging from cancer to depression and prevention to overtreatment. He's been reporting on health since 2005. You can follow him on Twitter or email him at email@example.com.