To protect your brain against dementia, start pedaling, study suggests

By Kristen Rogers, CNN

(CNN) — Cycling isn’t just good for the planet, your wallet and your fitness. Choosing this form of transportation for your errands instead of driving or taking the train may also help you prevent cognitive decline, a recent study found.

Riding a bike is associated with a 19% lower risk of all-cause dementia and a 22% lower risk of Alzheimer’s disease, compared with taking nonactive travel modes such as a car, bus or train, found the study that assessed nearly 480,000 participants from Great Britain and published in the journal JAMA Network Open.

Physical activity has long been associated with lower dementia risk in multiple studies, so much so that the 2024 Lancet Commission identified it as one of 14 factors responsible for preventing or delaying approximately 45% of dementia cases. More than 55 million people worldwide have dementia, a number expected to nearly triple by 2050.

“Although population-based evidence on the health effects of active travel remains scarce, systematic reviews have consistently highlighted its association with improved health outcomes, including a lower risk of diabetes,” the authors of the paper wrote. Few studies until now, however, have investigated the association between travel mode, dementia risk and structural brain changes, they added.

The study participants were recruited between 2006 and 2010 for the UK Biobank study, which has followed the health outcomes of more than 500,000 people age 40 to 69. Participants, who were age 56.5 on average, answered questionnaires about which of four transportation modes they had used most often to get around in the past four weeks, not including journeys to or from work: nonactive, walking, mixed walking (a combination of walking and nonactive travel modes) and cycling and mixed cycling (a combination of cycling and other modes).

Over a median follow-up period of 13.1 years, 8,845 participants developed dementia, and 3,956 adults developed Alzheimer’s disease. Walking and mixed walking were linked with a 6% lower risk of dementia and, interestingly, a 14% higher risk of Alzheimer’s disease. The research team also discovered that the strongest genetic risk factor for Alzheimer’s — the APOE ε4 gene — also had an influence. Participants without APOE ε4 had a 26% lower risk of dementia, while those with the genetic variant had a 12% lower risk.

Cycling and mixed cycling were also most associated with greater hippocampal volumes, the region of the brain responsible for memory and learning.

“This study is the first to show that cycling is linked not only to a lower risk of dementia but also to a larger hippocampus,” said Dr. Joe Verghese, professor and chair of neurology at Stony Brook University in New York, via email. Verghese was not involved in the study.

Cycling for brain health

The strengths of the study are impressive, but there are caveats, Dr. Sanjula Singh, principal investigator at the Brain Care Labs at Massachusetts General Hospital, said via email. She was also not involved in the study.

“Travel modes were self-reported at a single time point, so we don’t know how people’s habits changed over time,” said Singh, who is also an instructor of neurology at Harvard Medical School. “Most participants were White and healthier at baseline, so the results may not generalize to all communities.

“And, perhaps most importantly, because this is an observational study, it cannot prove that cycling directly prevents dementia,” Singh added. “It merely shows a found association.”

Older adults who cycle regularly are likely a healthier subgroup, and cycling may also serve as a marker of favorable genetics, with risk lowest among those without genetic susceptibility to dementia, Verghese said.

Participants who chose active travel modes were more likely to be women, nonsmokers, more educated, engaged in more physical activity in general and have a lower body mass index and fewer chronic diseases, the authors wrote. Cycling and mixed-cycling groups, specifically, were more often men and those who had healthier lifestyles and physical conditions than their peers.

The link between greater Alzheimer’s disease risk and the preference for walking could be explained by those participants potentially already having issues with balance or driving, said Dr. Glen Finney, a behavioral neurologist and director of the Memory and Cognition Program at Geisinger Health System in Wilkes-Barre, Pennsylvania.

Walking pace also matters, Finney, a fellow of the American Academy of Neurology, added. Leisurely walking, especially for short distances, may not be enough to get the full potential benefit compared with walking longer distances at a brisker pace. The study did not report on the frequency, pace or duration of participants’ walking or cycling habits.

Regardless, decades of research have shown that exercise is good for the brain, Verghese said. “Cycling may reduce dementia risk by improving cardiovascular fitness, increasing blood flow to the brain, supporting neuroplasticity, and improving metabolism.”

Cycling also requires more effort and different types of engagement from the brain, which may also contribute to any potential boost in protection against dementia, the authors wrote.

If you’re typically sedentary and want to start cycling, discuss with your doctor whether you’re healthy enough to begin immediately or whether you need to work up to it, Verghese said.

“Begin with short, safe routes on dedicated bike paths before moving into traffic,” Singh said. “Always wear a helmet, use reflective gear, and add lights if biking or walking at night. Stick to well-lit routes and, if possible, travel with a partner.”

Cycling even just once or a few times per week can make a difference, Singh added, and indoor stationary cycling — though not included in the study — is an option for those concerned about safety from traffic.

For walking, aim for brisk, purposeful treks, and build up your distance over time, Singh suggested. That could mean walking for at least 30 minutes daily, ideally at a level of intensity that makes talking a little difficult, Verghese said. Adults need at least 150 to 300 minutes of moderate aerobic activity or 75 to 150 minutes of vigorous aerobic exercise per week, according to the World Health Organization.

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