Exercise, Diet, Sleep and Brain Health

What the evidence says about keeping your brain healthy: aerobic exercise and BDNF, the MIND and Mediterranean diets, sleep, social connection, hearing and blood pressure — and why most 'brain training' apps disappoint.

Exercise

Physical activity has some of the strongest evidence for brain health. Exercise increases blood flow and levels of BDNF (brain-derived neurotrophic factor), which supports synaptic plasticity and the survival of neurons; in rodents, running boosts hippocampal neurogenesis. In a 2011 trial led by Kirk Erickson and Arthur Kramer, older adults who did a year of moderate aerobic walking showed about a 2% increase in hippocampal volume, while a stretching control group showed the typical age-related decline. Observational studies link regular activity with lower dementia risk, and exercise helps mood, sleep and anxiety.

Diet

The Mediterranean diet — rich in vegetables, fruit, whole grains, legumes, fish and olive oil — and the related MIND diet (which emphasises leafy greens and berries) are associated in observational studies with slower cognitive decline, but randomised trials have been mixed; a 2023 trial of the MIND diet found no significant cognitive benefit over a control diet that also involved mild weight loss. Overall healthy eating matters for brain health, largely through cardiovascular and metabolic health. Single "superfoods" and supplements (including ginkgo and most omega-3 pills) have generally not shown convincing benefits for cognition in healthy people.

Sleep, social life and mental activity

Adequate sleep supports memory and mood. Social connection is associated with lower risk of dementia and better mental health. Education and mentally engaging activities build cognitive reserve.

Risk factors you can change

The 2024 Lancet Commission on dementia identified 14 modifiable risk factors across life, estimating that addressing them could prevent or delay nearly half of dementia cases: lower education, hearing loss, high LDL cholesterol, depression, traumatic brain injury, physical inactivity, diabetes, smoking, high blood pressure, obesity, excessive alcohol, social isolation, air pollution and untreated vision loss. Treating hearing loss with hearing aids and controlling blood pressure are among the most practical steps.

Brain training apps

Practising a computerised game makes you better at that game, but evidence of transfer to everyday cognition is weak. In 2016 the company behind Lumosity agreed to pay $2 million to settle US Federal Trade Commission charges that it deceived consumers with unfounded claims. Learning genuinely new, challenging skills — a language, an instrument — combined with social interaction may offer more.