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Short Summary
Main recommendation: Keep doing your cognitively demanding hobbies, and add novel, challenging activities that build broad skills, such as learning a new language, a musical instrument, or a complex sport. The strongest evidence points to multi-domain interventions and processing speed training, which together have shown benefits for cognitive function and dementia risk in older adults.
Key Points
- Observational studies link continued cognitively engaging activities, such as lectures, volunteering, and crosswords, with slower cognitive decline and lower dementia rates, though reverse causation may partly explain this.
- Randomized trials show that novel cognitive activities, including language learning, complex movement, and musical training, improve function, particularly executive function.
- Multi-domain trials, including the Australian Maintain Your Brain study and the US POINTER trial, combined diet, physical activity, cardiovascular risk management, and brain training.
- A secondary analysis of the ACTIVE trial found processing speed training with booster sessions at one and three years was linked to significantly lower dementia risk about 20 years later, per Dr. Wood.
- Crossword puzzles and Sudoku are more meditative than truly challenging, so they build less cognitive capacity than learning new skills.
Details Worth Noting
- Concrete instructions: Keep your existing cognitively engaging hobbies and make them more demanding, for example by trying harder crosswords. Add at least one new skill that is both focused and challenging, such as learning a new language, instrument, or ball sport, and prefer broad skills that involve several motor, social, visual, and auditory tasks. Consider processing speed training, such as visual speed tasks where stimuli flash for progressively shorter durations and you must recall what appeared and where, with booster sessions over time. Address diet, physical activity, and cardiovascular risk factors alongside cognitive work, as multi-domain trials did.
- The ACTIVE trial in the 1990s had three training groups (memory, reasoning, and processing speed) and a control group, with participants in their 60s and 70s.
- Dr. Wood cited a Nature-journal analysis of about 1.2 million people showing processing speed tends to be stable until around 60, while reaction time slowly decreases from about the 30s.
- Broad, complex skills may transfer better to daily life than narrow digital brain training, because they activate multiple brain networks.
Bottom Line
Continue your current mentally demanding activities, but add a new, broad, challenging skill and consider processing speed training to protect cognitive function as you age.
