Cycling regularly in midlife can help reduce the risk of dementia, as well as maintaining brain health, a new large-scale study has found.

The study, which was carried out by researchers based in China and Australia and published this week in JAMA Network Open, aimed to investigate the long-term association between how people travel and dementia risk and brain structure.

The researchers assessed data collected over a 13-year spell from 479,723 participants of UK Biobank, a long-term biomedical database containing de-identified biological samples and genetic, lifestyle, and health information.

The participants, 54 per cent of whom were women, with an average baseline age of 56.5, were all dementia-free at the beginning of the study and able to walk.

They were asked what modes of transport they had used most often to get about in the previous four weeks, excluding their commute to and from work. These responses were then grouped into four categories: non-active (car or public transport), walking, mixed-walking (a combination of non-active transport and walking), and cycling and mixed-cycling (cycling combined with other modes).

Nearly half of the participants (49.1 per cent) were inactive; while 6.8 per cent were classified as walking-only, 37 per cent as mixed-walking, and seven per cent as cycling and mixed-cycling.

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Over the following 13 years, 8,845 cases of dementia and 3,956 cases of Alzheimer’s disease were recorded among the participants, identified by the researchers through hospital records and death registers.

According to the study’s categorisation, travel that incorporated cycling was associated with a lower adjusted risk of young-onset dementia, late on-set dementia, and Alzheimer’s, compared to non-active transport.

Cycling, either on its own or combined with other forms of transport, was also found to have a significant connection with higher hippocampal volumes, the researchers concluding that riding a bike represents “a promising approach for maintaining brain health”.

The hippocampus is a major part of the brain which plays an important role spatial memory and in consolidating short-term to long-term memory. It is one of the first regions of the brain to be damaged by Alzheimer’s disease.

“Our findings suggest that active travel modes, particularly cycling and mixed-cycling, are associated with higher hippocampal volumes,” Liangkai Chen, one of the Wuhan-based researchers involved in the study, told MedPage Today this week.

“The hippocampus is critical for memory and cognitive function, and greater volume is generally considered a sign of better brain health.

“This outcome could be attributed to the physical activity and aerobic exercise involved in cycling, which is known to have neuroprotective effects.

“Cycling, especially as a regular form of transport, may help increase blood flow to the brain, reduce inflammation, and stimulate neurogenesis, and requires higher cognitive engagement during travel, which could all contribute to the observed preservation of hippocampal volume.”

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The study noted, however, that participants without the apolipoprotein E ε4 (APOE ε4) gene variant, which is present in up to 15 per cent of the population, doubling or tripling their risk of Alzheimer’s, benefited more from cycling than those with the gene, though the researchers pointed out that they can also benefit from riding a bike.

“Individuals without the APOE ε4 gene variant appeared to derive greater benefits from active travel modes in terms of dementia risk reduction,” Chen said.

“Critically, however, our data indicate that APOE ε4 carriers can still benefit from cycling, though these benefits are likely attenuated due to the allele’s strong biological influence on neurodegeneration pathways.

“These results collectively suggest that promoting active travel, particularly cycling, remains a valuable public health strategy to enhance brain health across populations.”

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Meanwhile, participants in the mixed-walking group also possessed a lower risk of all-cause dementia compared to those in the inactive group – though the results for walking alone were mixed.

“Overall, the association of walking with brain health remains inconsistent and warrants further investigation,” the researchers said.

“Our results suggest that mixed-walking models, which combine walking with other forms of travel that require higher cognitive engagement (e.g. driving), may be more beneficial in reducing dementia risk than walking alone.”