The Optimal Remedy?

Not only does exercise enhance cognitive functions—ranging from executive abilities to memory—but simply walking briskly for 2.5 hours each week (approximately 30 minutes on weekdays) is known to improve blood pressure, cholesterol levels, energy, mood, mental health, and sleep quality, as per the American Heart Association.

An increasing volume of research indicates that physical activity is closely linked to happiness and may even act as a preventive measure against depression. Just a ten-minute walk can alleviate stress and anxiety. Furthermore, substantial evidence supports the notion that exercise improves overall physical health and decreases mortality risk from various causes.

The effort necessary to achieve these mental and physical benefits is manageable; one doesn’t need specialized gear or extensive workouts. In fact, the term “exercise” might deter many who lead sedentary lifestyles.

Health professionals, often quick to prescribe medications, should first consider recommending increased physical activity to enhance both physical and mental wellness.

How Does It Work?

The exact mechanisms through which physical activity benefits the brain remain somewhat elusive. However, scientists are making progress in understanding the connections.

Engaging in vigorous workouts triggers the release of chemicals that promote brain cell health and the formation of new blood vessels in the brain, as stated by Harvard Medical School. Additionally, exercise indirectly boosts mood, alleviates stress, and fosters improved sleep—all factors known to enhance cognitive abilities.

The effects of exercise are evident within the brain itself.

“Participating in a consistent, moderate-intensity exercise program for six months to a year correlates with increased volume in specific brain areas,” shared Scott McGinnis, a neurologist at Brigham and Women’s Hospital and an instructor at Harvard Medical School.

A meta-analysis of multiple studies examined the impact of exercise on the hippocampus, a brain region essential for verbal memory and learning. Researchers discovered that aerobic exercise significantly increased the left hippocampal volume compared to non-exercisers, preventing the usual shrinkage associated with aging, as reported in the journal Neuroimage in 2017.

A Protective Benefit

Physical activity appears to offer a protective effect on the brain overall.

In a compelling study that tracked the activity levels of 454 older adults who agreed to donate their brain tissue posthumously, researchers found that those who were more active—even with everyday tasks like housework—exhibited better memory and cognitive skills. Additionally, the brains of less active participants showed a greater number of lesions associated with Alzheimer’s disease.

“Exercise is a cost-effective way to enhance health, and our study indicates it may offer protective benefits to the brain,” stated Aron Buchman from Rush University Medical Center, the study's lead author, published in January 2019 in Neurology. “However, it’s essential to acknowledge that our study does not establish a direct cause-and-effect relationship. It’s possible that as individuals experience memory and cognitive decline, they may become less active. More research is needed to determine if increased activity genuinely benefits the brain.”

While further investigation is warranted, it is increasingly evident that some physical activity is better than none, and that more is even more beneficial.

A 2017 study published in Translational Psychiatry examined brain scans of 60 individuals aged 65 to 85 who exercised on stationary bikes three times weekly for 12 weeks.

The crucial discovery was that physical activity altered brain metabolism by inhibiting the accumulation of choline, which, in high levels, is known to contribute to neuronal loss in dementia patients. Elevated choline levels were found in the brains of a non-exercising control group.

“The rise in choline could indicate neurodegenerative processes,” noted Silke Matura, a study leader from Goethe University Frankfurt. “Thus, our finding of increased choline levels in the control group but not in the exercise group could suggest a neuroprotective effect of regular aerobic activity by potentially decelerating neurodegeneration.”

The question of whether adults can generate new brain cells, and if physical activity plays a role, has been contentious for years. However, recent studies suggest a growing consensus that it is indeed possible.

Broad investigations conducted in 2018 and 2019 confirmed that older adults can generate new neurons. The 2019 study headline read: “Adult hippocampal neurogenesis is abundant in neurologically healthy subjects and sharply declines in Alzheimer’s patients.” Recent findings in both rodent and human studies suggest that exercise facilitates this neurogenesis.

Strong Body, Strong Mind

If aerobic exercise can foster the creation of new brain cells, enhance memory, and improve cognitive clarity, what about other forms of exercise? Weightlifting has also been shown to benefit brain function, although fewer studies exist, and intensity appears to play a significant role.

Research by Teresa Liu-Ambrose at the University of British Columbia compared the effects of cardiovascular exercise and weight training on women showing early dementia symptoms.

“We found that only those who engaged in weight training exhibited notable improvements in both memory and executive functions,” Liu-Ambrose reported. “This contrasts with prior studies on healthy individuals that indicated cardiovascular exercises were beneficial. Neuroimaging revealed increased neural activity in brain areas responsible for memory and executive functions post-weight training.”

In another rigorous study, 100 men and women aged 55 to 86, who had mild cognitive impairment—a potential precursor to dementia—participated in a weightlifting program twice a week for six months. They lifted relatively heavy weights—80 percent of their maximum strength—and as their strength improved, their weights were adjusted upward.

Compared to control groups, these increasingly fit seniors experienced cognitive improvements that persisted even a year after completing the formal exercise program.

“The greater the strength gains, the more significant the cognitive benefits,” explained Yorgi Mavros, a researcher at the University of Sydney and the study's lead author, published in the Journal of American Geriatrics. “It’s crucial to engage in this activity frequently, at least twice a week, and with high intensity to maximize strength gains and cognitive benefits.”

Any Activity Is Beneficial

In conclusion, many researchers in this field echo a common sentiment:

“The evidence overwhelmingly suggests that exercise is one of the best things you can do for your physical and mental health,” asserted Stern, the Columbia professor.

When asked if this knowledge has motivated him to be more active, he replied, “I have made an effort to increase my weekly exercise. However, altering behavior is challenging. One strategy is to incorporate external motivation, like friends or trainers who are counting on you. Another approach is to find ways to weave exercise into your daily schedule. For instance, I pick up lunch from the hospital cafeteria and walk back to my office.”

Choosing stairs over elevators and integrating walks into your daily routine is sound advice, beneficial not only for brain health but overall wellness. Research indicates that you don’t need to spend hours in the gym to achieve meaningful health benefits:

• Walking just one hour a week may enhance longevity.
• Short bursts of intense exercise, such as climbing three flights of stairs multiple times a day, can improve fitness and elevate mood.
• Remarkably, firefighters capable of performing 40 push-ups in succession had a 96 percent lower risk of cardiovascular disease compared to those who could manage only ten.
• A mere 13 minutes of weightlifting three times a week can yield the same strength improvements as longer sessions.

Numerous studies have identified various activities that can contribute to physical fitness.

Dancing: Research shows that dancing not only helps delay dementia but is also more effective than traditional endurance workouts in enhancing balance among older adults.

Gardening: A single 20-minute gardening session—including tasks like cleaning, digging, raking, planting, and watering—boosted levels of brain-healthy growth factors in a group of elderly South Koreans.

Any Activity?: A study involving 800 Swedish women published in Neurology in February 2019 discovered that those with high physical activity levels were 52 percent less likely to develop dementia over time compared to inactive individuals. This activity included walking, gardening, bowling, or biking for at least four hours weekly, alongside regular intense exercises like running, swimming, or participating in competitive sports.

While vigorous exercise should not be neglected, another study of 1,462 Swedish women revealed that those with high fitness levels saw dementia onset delayed by an average of 9.5 years compared to those with moderate fitness.

While no single study provides definitive proof, the overall conclusion is clear: leading a sedentary lifestyle is unwise.