What Exercise Can Do Now, and What It Cannot

You have been told exercise is good for the brain. After a diagnosis, the evidence is about fitness, balance and falls more than memory.

Will exercise slow my dementia down?

Probably not by itself, if you already have dementia. It does other things that matter a great deal, and in mild cognitive impairment the evidence is more encouraging.

Most headlines about exercise and the brain come from prevention research: large studies of people without dementia, some of whom are at higher risk. Those findings may be real, but they are not about you once you have a diagnosis. The question after diagnosis is different, and so is the answer.

The largest trial in people who already had dementia was DAPA, published in The BMJ in 2018. It enrolled 494 people with mild to moderate dementia, average age 77, in England. Two-thirds did supervised gym sessions twice a week for four months, combining moderate to high intensity aerobic and strength training, plus home exercise. Their fitness improved. But a year later, their scores on the main thinking test were slightly worse than those of people who had usual care. The difference was small and its meaning unclear. The researchers concluded that this kind of program cannot be recommended as a treatment for cognitive decline in dementia. It also did not improve daily activities, falls or quality of life.

A 2015 Cochrane review of 17 trials found something similar: no clear evidence that exercise programs improve thinking in dementia, and some evidence that they may help with daily activities, though the certainty was very low.

None of this means exercise is pointless. It means its job is different from what people are told.

What about mild cognitive impairment?

The news is better here, though it comes with a caveat about how it was measured.

The EXERT trial, reported in Alzheimer's & Dementia in 2025, followed about 300 inactive older adults with amnestic mild cognitive impairment for a year. Half did moderate to high intensity aerobic training and half did lower-intensity stretching, balance and range-of-motion work, three to four times a week with a YMCA trainer.

Thinking stayed stable in both groups for the year. Both declined less than a similar group from another study who received usual care. That comparison group was not part of the same randomized trial, so the result is encouraging rather than proof. The useful finding for you: the gentler program did as well as the harder one.

What does exercise actually do for me now?

It keeps you steadier on your feet, stronger for the things you do every day, and less likely to fall. Those are not small things.

Falls are one of the main ways people with dementia lose independence, through injuries, hospital stays and the fear of falling again. A 2019 Cochrane review of 108 trials and more than 23,000 older adults living at home found that exercise reduced the rate of falls by about 23%. Programs built mainly on balance and functional exercises had high-certainty evidence. Tai chi may help too, though the evidence was less certain.

Those trials were in older adults generally, not only people with dementia. But people with dementia fall more often, which makes the benefit more relevant, not less.

Exercise also gets you outside, around other people and into a routine. Those things help with mood and sleep in their own right.

What kind of exercise should I do?

The kind you will keep doing. Aim for balance, strength you can use and regular walking, preferably with other people.

• Balance work. Standing on one foot near a counter, heel-to-toe walking, a tai chi or balance class. Balance work has the strongest evidence for preventing falls.
• Functional strength. Standing up from a chair without using your hands, stairs, carrying groceries. Strength you use every day.
• Walking. Outdoors if you can. Take your phone and tell someone your route if you walk alone.
• Something social. A class, a walking group, a regular partner. You are more likely to keep going, and the company is part of the benefit.

Gentle is fine. In EXERT, stretching and balance did as well as harder training. If you were a runner or a lifter before the diagnosis and love it, keep going if your doctor agrees. If you were not, do not let anyone guilt you into a punishing program on the promise that it will protect your memory.

Is there anything I should be careful about?

Talk to your doctor before starting something new, especially with heart problems, dizziness, or a recent fall.

• Ask about balance first if you have had a fall or feel unsteady. A physical therapist can assess you and design a program, and Medicare Part B covers outpatient physical therapy when your doctor orders it.
• Watch for dizziness from medications, especially blood pressure medicines and some antidepressants.
• Drink water and eat around exercise. Thirst cues weaken with age.
• Carry ID and a phone when you exercise alone.