Study Finds Aerobic Fitness in Midlife Could Reduce Dementia Risk

Study Finds Aerobic Fitness in Midlife Could Reduce Dementia Risk

A new study suggests that improving aerobic fitness in middle and older age may help reduce the risk of dementia, including Alzheimer’s disease.

The study, led by Weili Xu, a professor at the Aging Research Center of the Karolinska Institute in Stockholm, highlights the importance of cardiovascular fitness in preventing dementia, even for those with a genetic predisposition to Alzheimer’s disease. “Our research emphasizes how critical cardiovascular fitness is in reducing the risk of dementia,” Xu said. “Encouraging gradual improvements in fitness is a practical and effective approach to supporting brain health across diverse populations.”

The study found that individuals in the best cardiorespiratory shape had significantly better cognitive function, with only a 0.6% long-term risk of developing dementia, compared to those who were less fit. This fitness advantage delayed the onset of dementia by an average of 1.5 years.

Cardiorespiratory fitness, developed through regular aerobic exercise, improves oxygen intake in the lungs and heart, allowing individuals to perform high-intensity activities for longer periods without fatigue.

The benefits were even more significant for people genetically at risk for Alzheimer’s. Those with higher levels of cardiorespiratory endurance had a 35% lower relative risk of developing the disease.

Dr. Richard Isaacson, a preventive neurologist at the Institute for Neurodegenerative Diseases in Florida, who was not involved in the study, praised the results: “Exercise is like a miracle ‘drug’ with brain-boosting effects,” he said. He added that combining regular exercise with a healthy diet, blood pressure and blood sugar management, and good sleep could offer even greater benefits in preventing dementia.

The Importance of Cardiorespiratory Fitness
Studies show that low levels of cardiorespiratory fitness are strongly linked to cardiovascular disease, heart attacks, and early death, including from cancer. Without regular exercise, cardiorespiratory fitness declines with age, dropping 3% to 6% per decade in one’s 20s and 30s and increasing to over 20% per decade after 70.

This new study, published in the British Journal of Sports Medicine, followed over 61,000 dementia-free individuals aged 39 to 70, who enrolled in the UK Biobank. Researchers assessed their fitness levels when they joined the study, along with cognitive function and genetic risk. Twelve years later, the study examined how these baseline measures related to any diagnoses of dementia.

“The study showed a clear, dose-dependent effect of exercise fitness on cognitive performance,” Dr. Isaacson said. “Cardiorespiratory fitness can positively impact different types of memory, such as recalling specific words and numbers or remembering future actions, like making an appointment.”

Being aerobically fit also enhances brain speed, making thinking faster and more efficient. “Think of it like a car: the fitter you are, the faster you can shift into higher mental gears,” Isaacson explained.

Study Limitations
While the study found promising results, it was observational, meaning no direct cause-and-effect conclusions can be made. Cardiologist Dr. Valentin Fuster, who was not involved in the study, cautioned that those with low fitness levels tend to have more health problems, such as hypertension, diabetes, high cholesterol, and obesity—all of which are risk factors for cardiovascular disease and brain damage.

“These health conditions can affect the small blood vessels in the brain, leading to vascular dementia or accelerating Alzheimer’s,” Dr. Fuster noted. “Individuals with higher fitness levels are often better at managing these risk factors, protecting both their heart and brain health.”

How to Improve Aerobic Fitness
To improve cardiorespiratory fitness, experts recommend engaging in aerobic exercises that raise your heart rate. These could include cycling, brisk walking, jogging, swimming, dancing, hiking, or high-intensity interval training (HIIT), which combines short bursts of intense activity with lower-intensity recovery periods.

Dr. Fuster advises aiming for at least 30 minutes of aerobic exercise, five days a week, at an intensity that makes it hard to hold a conversation. Regular exercise not only improves cardiovascular and brain health but also helps with weight management, mood stabilization, sleep, and longevity.

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