Exercise

Exercise refers to regular physical activity, including aerobic activity, resistance training, and movement habits that improve fitness over time. In the neurodegeneration landscape, exercise is one of the most important lifestyle interventions because it has broad effects on vascular health, metabolic function, mobility, and mood. Major prevention guidance supports physical activity as a core part of reducing risk for cognitive decline and related conditions.

Exercise is a major intervention in its own right, not just as a supporting habit. It both improves general health and helps preserve the functional systems that allow people to stay cognitively, socially, and physically engaged over time.

Sauna is an emerging intervention that broadly fits under the exercise umbrella, but only as a smaller adjunct. It is not yet on the same evidence level as exercise.

Biological rationale

Exercise improves many of the upstream conditions that shape brain aging. It can lower blood pressure, improve insulin sensitivity, support healthier body weight, improve endothelial and cardiovascular function, and reduce overall vascular burden. All of these are thought to support long-term brain health. Exercise may also support cognition and resilience more directly through improved mood, better sleep, greater functional reserve, and possibly enhanced neuroplasticity.

Sauna is biologically interesting because heat exposure may improve vascular and autonomic function, but the dementia-related evidence remains much more preliminary and largely observational.

Evidence strength assessment

Strong for exercise, emerging for sauna

Exercise has some of the best support in the lifestyle literature and is specifically recommended by WHO for reducing risk of cognitive decline. The exact ideal dose and modality are still debated, but the overall evidence that regular physical activity is beneficial for brain health is strong enough that it should be considered a core pillar of prevention.

Sauna’s evidence should be handled much more cautiously. The prospective Finnish data are interesting and suggest a possible association between more frequent sauna use and lower dementia risk, but this is not the same as proof that sauna itself prevents neurodegeneration.

Limitations

Even for exercise, the literature is not perfectly clean. Physical activity is difficult to measure precisely, intervention trials vary widely, and some benefits may be mediated indirectly through improved vascular and metabolic health rather than direct effects on disease pathology.

For sauna, confounds are a major concern. People who use sauna regularly may also differ in exercise habits, socioeconomic status, baseline health, and social patterns.

Sources

Tari, A. R., et al. (2025). Neuroprotective mechanisms of exercise and the importance of cardiorespiratory fitness in promoting healthy brain ageing.
Yau, W. Y. W., et al. (2025). Physical activity as a modifiable risk factor in preclinical Alzheimer’s disease.
Laukkanen, T., Kunutsor, S., Kauhanen, J., & Laukkanen, J. A. (2017). Sauna bathing is inversely associated with dementia and Alzheimer’s disease in middle-aged Finnish men.
Izquierdo, M., et al. (2025). Exercise for dementia prevention: Evidence for a precision-medicine approach.
Livingston, G., Huntley, J., Liu, K. Y., et al. (2024). Dementia prevention, intervention, and care: 2024 report of the Lancet standing Commission.