Can exercise lower my risk of dementia?

What the science says now

Is being fitter linked to less dementia?

In large studies, yes. A review pooled 12 studies covering 2,317,053 people. Adults with the highest fitness had about half the dementia risk of adults with the lowest (0.53). Each 1-MET step up in fitness went with a figure of 0.93. A MET is a standard way of measuring how much effort your body can handle. (Exercise and the brain: higher fitness linked to about half the dementia risk · Geroscience)
In people; observational.

Does it help to get fitter later on?

In four of those studies, people who raised their fitness or kept it higher had a lower risk of dementia or cognitive impairment (trouble with memory and thinking). (our story · Geroscience)
In people; observational.

What if memory problems have already started?

In a Korean study of 116,563 people with mild cognitive impairment or dementia, any aerobic activity went with a lower chance of dying during the study. For high activity the figure was 0.636, compared with inactive people. (Exercise and the brain: even a little activity linked to fewer deaths in memory loss · GeroScience)
In people; observational.

How much is enough?

In trials of adults 60 or older with mild cognitive impairment, the most reliable gains in thinking skills came at about 300 to 1,000 METs-min per week. Higher amounts showed plateaus or small declines. This measured thinking skills, not dementia, and the certainty of the evidence was low to moderate. (Exercise and the brain: a moderate weekly dose gave the best gains for thinking · PeerJ)
In people; trials.

Does an active social life add anything?

From age 50, people high in both exercise and social-and-mental activity could expect about 24.7 years free of cognitive impairment. People low in both could expect 17.5. (Healthy aging: exercise plus an active social life means more memory-healthy years · Alzheimer’s & Dementia)
In people; observational.

For general guidance on being active, see the Physical Activity Guidelines for Americans (HHS).

What we don’t know yet

Most of this research watched people over time. It shows a strong link, not proof that exercise prevents dementia. Too few studies looked at Alzheimer’s disease on its own to draw a conclusion. The best-dose finding comes from people who already had mild memory problems. We also don’t know the ideal routine for everyone else.

When to talk to your doctor

Talk with your doctor if you have noticed changes in your memory or thinking. Ask before starting a new kind of exercise, especially if you have heart or blood vessel conditions. You can also ask about your blood pressure and a hearing check.

Talk about it at dinner

Ask everyone: “What is a walk we would all enjoy?” Then pick a day this week. On the walk, play a game of naming animals or foods from A to Z.