We know that exercise benefits the mind, body, and soul, but new research has revealed that high-intensity interval training (HIIT) can not only improve brain function but also delay the onset of dementia.

A study conducted by researchers from the University of Queensland, Australia, found that exercise consisting of short bursts of intense work followed by quick recovery periods was most beneficial for boosting brain health among participants aged 65 to 85.

According to the Alzheimer's Association, an estimated 6.9 million Americans aged 65 and older are living with Alzheimer's in 2024, and it is the most common type of dementia. The recent research demonstrates that exercises that quickly increases the heart rate, such as jumping jacks and burpees, can sharpen the brain for up to five years.

Newsweek discussed the research published in the journal Aging and Diseaseon July 8 with two doctors and a health professional.

The study, involving 151 participants aged 65 to 85 with no cognitive deficits, compared three six-month exercise regimens: low intensity (LIT), medium intensity (MIT), and HIIT.

Each participant engaged in 72 supervised exercise sessions over six months, with cognitive testing and blood collection occurring monthly, and continuing for up to five years. MRI scans were conducted at the start, at six months, and at 12 months to assess changes in brain structure and function.

After six months, only the HIIT group showed significant improvements in memory and learning abilities. Brain scans revealed that HIIT helped prevent the typical age-related shrinkage of the hippocampus, an important area of the brain for memory, and improved the connections between different brain regions.

Additionally, the HIIT group had beneficial changes in blood levels of certain proteins and hormones linked to brain health, suggesting these could help in choosing the best exercise routines for maintaining cognitive function.

Newsweek discussed the findings with John Showalter, who is the chief strategy officer at Linus Health, a digital health company enabling early detection of Alzheimer's and other dementias.

He said: "The hippocampus is the part of the brain associated with memory formation, and it's the only part of the brain that can continue to grow through adulthood. Shrinking of the hippocampus is correlated with Alzheimer's.

"Exercise releases hormones and other compounds that can spur growth of the hippocampus, or help slow its shrinkage. HIIT also helps build muscle and decreases fat faster than low- or mid-interval training. Losing fat can help the body better manage insulin, which is a contributor to amyloid plaque formation."

This study aligns with broader research underscoring the cognitive benefits of physical exercise. According to the Alzheimer's Society, regular physical activity can reduce the risk of developing dementia by about 28 percent, and specifically Alzheimer's disease (AD) by 45 percent​. The Stanford Center on Longevity states that regular exercise enhances neuroplasticity, the brain's ability to form and strengthen neural connections, crucial for maintaining cognitive functions in aging people​.

Newsweek also spoke to Muhammad A. Arshad, a neurologist affiliated with Memorial Hermann, a health system in southeast Texas. He said: "Exercised-mediated responses of biomarkers as predictors for improved hippocampal functional outcomes offers a quantifiable metric to provide an effective exercise regimen.

"The improvement and long-term retention of hippocampal learning ability following HIIT exercise provides a new insight into how the elderly could be insulated from cognitive decline even though their exercise capabilities may decline with advanced age. This approach could greatly enhance the capacity of clinicians to tailor personalized exercise paradigms, including those at risk of cognitive decline."

While the study found that three 36-45 minute HIIT sessions per week were most beneficial, John Showalter, a primary care physician in Danville, Pennsylvania, offers another perspective.

Showalter told Newsweek: "I want to stress that people shouldn't think exercise isn't helpful for cognitive health unless it's HIIT, which not everyone is capable of performing.

"In this particular study, there wasn't a 'couch potato' group to which researchers compared the lower intensity exercisers; if there had been, low-intensity exercisers most likely would have shown improvement over the non-exercisers. Many forms of low-intensity exercise, including walking and tai chi, have been proven to delay and lessen mild cognitive impairment, which is the precursor to dementia. Anything is better than nothing."

He urges people to check with their physician before starting a new exercise program to ensure it's safe.

He said: "Patients with restrictions due to balance, mobility, frailty or other issues should be referred to a physical therapist who can design a safe exercise program for them. According to earlier research conducted by the American College of Cardiology, HIIT is safe even for recent cardiac patients, though participants who are unused to it should build up to that level gradually."

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