Mentally Stimulating Activities
One of the most consistent findings in the brain health literature is that people who lead intellectually engaged lives — through education, mentally demanding work, and cognitively stimulating leisure activities — are significantly less likely to develop dementia, and when they do develop it, show symptoms later despite having equivalent levels of brain pathology. This is the concept of cognitive reserve: the brain's built-up capacity to withstand damage while maintaining function. A 2025 systematic review and meta-analysis found that participation in cognitively stimulating leisure activities was associated with a 22–42% lower risk of dementia and cognitive impairment, with consistent benefits seen across memory, processing speed, and executive function (Deng et al., 2025, Ageing Research Reviews). The association is robust across cultures, follow-up periods of up to 20 years, and different methods of measuring both activity and cognitive outcomes.
A large Australian cohort study of over 10,000 older adults provides a particularly clear picture of which activities matter most. Regular engagement in adult literacy activities — taking education classes, using a computer, writing letters or journals — and active mental activities such as games, cards, chess, and crossword puzzles was independently associated with reduced dementia risk over 10 years (Xu et al., 2023, JAMA Network Open). Passive social activities like attending outings showed weaker associations. The common thread among the most protective activities is that they involve active mental engagement — processing new information, solving problems, generating output — rather than passive consumption. Reading counts. Writing counts. Learning a new skill counts. The brain responds to novelty and challenge, and the evidence suggests that continuing to seek out intellectually demanding activities throughout midlife and later life builds the reserve that protects against cognitive decline.
Bilingualism offers one of the most striking illustrations of how cognitive reserve works in practice. Studies consistently find that lifelong bilingual individuals develop symptoms of dementia four to five years later than monolinguals with equivalent levels of brain pathology — effectively demonstrating that a lifetime of managing two language systems builds enough reserve to mask the effects of significant neurodegeneration. Learning a new language in later life, taking up a musical instrument, pursuing formal education, and engaging in complex work or creative projects all appear to contribute to this reserve in similar ways. The practical implication is encouraging: it's never too late to start building cognitive reserve, and the activities that build it most effectively are often ones that are intrinsically rewarding. The best mentally stimulating activity is the one you'll actually keep doing.
Want to go deeper? Module 9 of the Brain Health for Life course — Use It or Lose It? — covers the full science of cognitive reserve, the evidence for mentally stimulating activities across the lifespan, and practical strategies for building intellectual challenge into your daily routine. You'll also find guidance on how to think about formal brain training programs — covered in a companion page on this site.
Key References
Deng, Y., et al. (2025). Cognitive leisure activities and future risk of cognitive impairment and dementia: systematic review and meta-analysis. Ageing Research Reviews.
https://doi.org/10.1016/j.arr.2024.102627
Krell-Roesch J, Vemuri P, Pink A, et al. Association between mentally stimulating activities in late life and the outcome of incident mild cognitive impairment, with an analysis of the APOE ε4 genotype. JAMA Neurol. 2017;74(3):332–338. doi:10.1001/jamaneurol.2016.3822
Xu, H., Yang, R., Qi, X., et al. (2023). Lifestyle enrichment in later life and its association with dementia risk. JAMA Network Open, 6(7), e2323690.
https://doi.org/10.1001/jamanetworkopen.2023.23690
Bialystok, E. (2021). Bilingualism: pathway to cognitive reserve. Psychological Science in the Public Interest, 22(1), 1–40.
https://pmc.ncbi.nlm.nih.gov/articles/PMC8035279/
