The research, ranked

Deep dives with a What Matters chart: every factor the evidence ranks for one outcome, sized by its own study number, and answerable right on the chart so you can see where you sit.

11 deep divesEvidence

11 deep dives · the badge is the strength of the evidence behind each

• 🧖Does sauna add years?Evidence: Low−40% all-cause death risk over 20 years for Finnish men taking a sauna 4 to 7 times a week, compared with once a week. Observational, one cohort, and still the best data there is.
• 🌳What runs in familiesEvidence: Moderate<10% of how long you live is explained by your genes, per 400 million family-tree records. Spouses’ lifespans correlate almost as much as siblings’, so most “family resemblance” is habits, not DNA.
• 👂Hearing, vision, brainEvidence: Moderate−48% less cognitive decline over three years in at-risk older adults who got hearing aids, in the ACHIEVE randomized trial. The biggest single modifiable dementia factor is also one of the most treatable.
• 🐾Do pets add years?Evidence: Low4 of 8 kinds of pet with any measured link to lifespan: dogs, cats, fish and birds. Horses, rabbits and guinea pigs, reptiles and other animals have never been followed to see how long their owners live, so they get no number, not zero.
• 🥦Plants and your brainEvidence: Low−23% less dementia over nine years in the third of 60,298 UK Biobank adults eating closest to a Mediterranean pattern, versus the third furthest from it. The one diet number on the dementia What Matters chart.
• 🛌Sleep and lifespanEvidence: Low7.9% of all deaths in a cohort of 172,321 US adults were attributable to suboptimal sleep patterns. Adults with all five healthy sleep traits were projected to live 4.7 years longer for men and 2.4 for women.
• ☕How to sleep betterEvidence: Low−45 min of total sleep per night when caffeine is taken too close to bed, across 24 controlled studies, largely without the sleeper noticing.
• 🧩Your Alzheimer’s riskEvidence: Low15–20 yrs before the first symptom is when Alzheimer’s pathology starts accumulating, which makes your 40s and 50s the decade that counts.
• 🎮Lower your cognitive ageEvidence: Very low13.7 yrs younger: how frequent video gamers (5+ hours a week of one kind of game) scored on memory, reasoning and verbal tests compared with non-gamers of the same age (Brain and Body study).
• 🦷Teeth, gums and lifespanEvidence: Low+24% higher risk of incident coronary heart disease for people with periodontal disease, pooled across 7 good-or-fair-quality cohort studies (range 1.24 to 1.34 depending on how periodontal disease was defined). One of the most consistent single findings in this page’s evidence.
• 🧠How to escape dementiaEvidence: Moderate45% of dementia cases worldwide are attributable to 14 risk factors you can act on, most of them decades before symptoms.