Contrary to fears of 'digital dementia,' some research indicates that people over 50 who regularly use digital devices experience lower rates of cognitive decline. While the causal link is still being studied, it challenges the narrative that screen time is inherently harmful for older minds.

A 40-year longitudinal study of Swedish women found a powerful correlation between mid-life fitness and late-life cognitive function. Women who were categorized as "high fit" in their 40s experienced, on average, nine more years of good cognitive health in their 80s compared to their low-fit counterparts.

Repetitive mental exercises like crossword puzzles merely reinforce existing neural pathways. To maintain cognitive health and build new connections, one must engage in novel challenges like learning a new language or skill.

A long-term study found many nuns had brains full of Alzheimer's plaques post-mortem, yet displayed no cognitive decline in life. Their constant social responsibilities and interactions acted as a continuous mental challenge, building new neural pathways that bypassed the damaged areas.

Retirement poses a significant health risk. The daily schedule, external expectations, mental challenges, and social network provided by a job are crucial for brain health. Their removal can lead to accelerated cognitive decline and social isolation.

Actively studying new information daily, as if preparing for an exam, builds profound mental and physical resilience. This "brain building" uses new nerve cells that would otherwise become toxic waste. The act of deep thinking strengthens the brain, calms the mind, and enhances your ability to handle stress.

The benefit of mindfulness isn't just bouncing back from stress (resilience). For high-demand professionals, consistent practice created "pre-resilience"—it prevented the typical decline in attention and mood from happening in the first place. Their cognitive performance remained stable through high-stress periods, rather than dipping and recovering.

After age 25, the brain stops changing from passive experience. To learn new skills or unlearn patterns, one must be highly alert and focused. This triggers a release of neuromodulators like dopamine and epinephrine, signaling the brain to physically reconfigure its connections during subsequent rest.

Contrary to popular belief, research doesn't support that being bilingual raises IQ or executive function. Its most significant scientifically-backed cognitive benefit is more practical: it appears to delay the onset of dementia by several years, making it a valuable public health tool.