Cycling protects the brain against dementia, a study finds

Cycling doesn’t just benefit the planet, your wallet, and your physical fitness. According to a recent study, choosing a bike instead of a car or train for everyday errands may also help prevent cognitive decline.

Cycling is associated with a 19% lower risk of all types of dementia and a 22% lower risk of Alzheimer’s disease compared to passive modes of transport such as cars, buses, or trains. This was shown by a study of nearly 480,000 people in the United Kingdom, published in the scientific journal JAMA Network Open.

Physical activity has long been linked by numerous studies to a lower risk of dementia—so much so that in 2024 the Lancet Commission identified it as one of 14 key factors that could help prevent or delay up to 45% of dementia cases. More than 55 million people worldwide are currently living with dementia, and this number is expected to almost triple by 2050.

“Although evidence from population-based studies on the health effects of active transport is still limited, systematic reviews have repeatedly pointed to its association with better health outcomes, including a lower risk of diabetes,” the study authors wrote. They added, however, that only a small number of studies have so far examined the relationship between mode of transport, dementia risk, and structural changes in the brain.

Passive and Active Transport and Genes

Participants in the study were recruited between 2006 and 2010 as part of the UK Biobank study, which tracks health outcomes in more than 500,000 people aged 40 to 69. The participants, whose average age was 56.5 years, answered questions about which of four modes of transport they had used most often during the previous four weeks (commuting to and from work was not included):

• passive transport (car, bus, train),
• walking,
• a combination of walking and passive transport (“mixed walking”),
• cycling and a combination of cycling with other modes of transport (“mixed cycling”).

Into traffic with caution only

Over the 13 years of follow-up, 8,845 participants developed dementia and 3,956 developed Alzheimer’s disease. Walking and mixed walking were associated with a 6% lower risk of dementia, but also with a 14% higher risk of Alzheimer’s disease. Researchers also found that the APOE ε4 gene—the strongest known genetic risk factor for Alzheimer’s disease—had a significant impact on the results. Participants without this genetic variant had a 26% lower risk of dementia, while APOE ε4 carriers had a 12% lower risk (still significant, but with a smaller effect).

Cycling changes the brain

Cycling and mixed cycling were also most strongly associated with a larger hippocampal volume—an area of the brain important for memory and learning. “This study is the first to show that cycling is associated not only with a lower risk of dementia, but also with a larger hippocampus,” said Dr. Joe Verghese, professor and head of neurology at Stony Brook University in New York, who was not involved in the research.

However, Dr. Sanjula Singh, lead researcher at Brain Care Labs at Massachusetts General Hospital, has reservations about the study. “Participants reported their mode of transport only once, so we don’t know how their habits changed over time,” said Singh, who also teaches neurology at Harvard Medical School. “Most participants were of White ethnicity and healthier at baseline, so the results may not be generalizable to all communities. And perhaps most importantly: because this is an observational study, it cannot prove that cycling directly prevents dementia,” she added.

Correlation or causation?

“It only shows that there is an association between cycling and a lower risk of dementia.” Older adults who regularly cycle are likely to belong to an overall healthier subgroup of the population, and cycling may also be a marker of favorable genetic makeup, with the lowest dementia risk seen among those without a genetic predisposition, said Dr. Joe Verghese.

The relationship between a higher risk of Alzheimer’s disease and a preference for walking may be explained by the fact that these participants may already have had problems with balance or driving, said Dr. Glen Finney, a behavioral neurologist and director of the memory and cognition program at the Geisinger Health system in Pennsylvania. According to Finney, who is a member of the American Academy of Neurology, walking speed also plays a role.

Even fast walking benefits the brain

Leisurely, recreational walking—especially over short distances—may not be sufficient to deliver the full benefits for the brain, unlike longer and more brisk walks. However, the study did not specify how often, how fast, or how long participants walked or cycled.

Move, move, move

Either way, decades of research show that physical activity benefits the brain, said Dr. Joe Verghese. “Cycling may reduce the risk of dementia by improving cardiovascular fitness, increasing blood flow to the brain, supporting neuroplasticity, and improving metabolism.” The study’s authors also noted that cycling requires greater effort and engages multiple parts of the brain, which may further contribute to protection against dementia.

If you spend most of your time sitting and want to start cycling, Verghese recommends first consulting your doctor to determine whether you are medically ready or whether you should begin gradually. “Start with short, safe routes on dedicated cycle paths before venturing into traffic,” advised Dr. Sanjula Singh.

Cycling even once or a few times a week can have an impact, Singh added. When it comes to walking, she recommends brisk, purposeful walks and gradually increasing distance. This can mean walking for at least 30 minutes a day, ideally at an intensity where you are slightly out of breath, said Verghese. According to the World Health Organization, adults should aim for at least 150–300 minutes of moderate-intensity aerobic activity per week, or 75–150 minutes of vigorous-intensity aerobic exercise.

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