People with mild memory loss or those who have been diagnosed with Mild Cognitive Impairment (MCI) may be at increased risk of developing dementia. Alzheimer’s researchers hope to find a treatment that will stop the progression of memory loss and prevent people with mild cognitive problems from developing Alzheimer’s or another dementia.
But with several potential treatments failing in clinical trials (gingko, Tarenflurbil , Flurizan and Alzhemed), the hope for a new drug to slow memory loss is fading.
One treatment does show promise, though: exercise.
Fitness for the Ageing Brain Study (FABS) enrolled 170 people who complained about their memory. Their average age was 69, and more than half met the criteria for a diagnosis of MCI. Those who took part in an exercise program actually improved their scores on tests of memory and thinking. Scores for those in the “usual care” group went down.
trial conducted by Laura Baker, Assistant Professor at the University of Washington and her colleagues, measured the effect of aerobic exercise on memory and thinking in 33 people diagnosed with MCI. Results showed that exercise improved women’s scores on multiple tests of memory and thinking. Men showed improvement on one test only, and exercise seemed to affect their hormones and metabolism differently [more on this below].
Second, a population-based study led by Yonas Geda, Associate Professor of Psychiatry and Psychology at Mayo Clinic, examined whether exercise decreases the risk of developing Mild Cognitive Impairment in the first place. Of the 1324 non-demented participants ages 70 to 89, 198 met the criteria for MCI. Those who reported they had engaged in moderate exercise had a lower probability of having MCI (as much as 39% lower for those who had exercised in midlife) than those who reported no exercise.
These studies are promising, but larger studies are needed to confirm results and answer some basic questions:
How much exercise is needed to make a difference?
It’s not clear how much exercise you need to help your memory. In the Mayo Clinic population study, only moderate exercise (but not light or vigorous exercise) was associated with reduced odds of having MCI. The following activities qualified as moderate exercise for purposes of this research:
- Brisk walking
- Strength training or weight lifting
- Doubles Tennis
- Martial arts
- Weight lifting
- Golfing without using a golf cart.
In their Archives of Neurology article describing this study, Dr. Geda and his colleagues point out that light and vigorous exercise were also associated with reduced odds of MCI, but the association was not statistically significant. A larger study might show that any level of exercise improves memory.In the FABS study, people in the exercise program were asked to exercise three times a week in blocks of 50 minutes. Fast walking was the main activity, but other exercises could be added. In the University of Washington study, people in the exercise program did high intensity aerobic exercise four times a week for 45 to 60 minutes.
“I think it's important to emphasize that although we examined the effects of high intensity aerobic exercise, it is possible that lower intensity exercise will also be beneficial,” says Dr. Baker, discussing her trial at the University of Washington. “Studies are now in process that will help to identify the minimum requirements of exercise (how much, how often, etc.) that will still result in cognitive improvement. Until we know these answers though, there is enough evidence to suggest that any physical activity is good for us. Exercise improves mood, reduces stress, lowers blood pressure, increases metabolism and insulin response in the body, increases blood flow, and boosts the immune system, to name only a few benefits.”
Do women benefit from exercise more than men?
In the same University of Washington trial, men didn’t show as much improvement as women. Exercise also seemed to affect their metabolisms and hormones differently.
“The sex differences still need to be examined more closely,” Dr. Baker says. “In our study, the men benefited, but the magnitude of improvement was not as great as it was for the women. All of the men in the aerobic group, however, reported feeling MUCH better. It may be that the men will need to exercise for a longer period of time before we see the same magnitude of cognitive benefit….In larger studies, it may be that the sex differences disappear.”
Why does exercise help memory and thinking?
It’s also not clear why exercise helps memory and thinking. In her presentation at the MCI Symposium, Dr. Lautenschlager speculated the benefits could come from:
- increased blood circulation in the brain
- a change in brain metabolism
- a reduction in depression (although the FABS study did not show that this was the case).
Dr. Geda and his colleagues list other possible mechanisms:
- increased production of neurotrophic factors (proteins that control what brain cells do and whether they survive). The University of Washington study showed that exercise did increase these proteins in women.
- growth of new brain cells. A recent study by the U.S. National Institute on Aging and University of Cambridge researchers showed that mice that run grow more new brain cells than inactive mice. [Read Danny George’s perspective on this at the Myth of Alzheimer’s blog.]
- switching genes that control changes in the structure and organization of the brain on and off.
Although results of the clinical trials so far suggest that exercise directly affects memory, the Mayo researchers noted that the results of their population study might be due to lower rates of heart and vascular disease in exercisers, or a tendency of exercisers to have healthier lifestyles overall.
How likely is it that people with memory loss will stick to an exercise program?
In the two clinical trials, researchers took care to help exercisers stay with the programs. The University of Washington study exercisers worked out with personal trainers. These trainers provided structure, accountability, encouragement and social support, according to Dr. Baker. Participants in the FABS home-based exercise program attended an hour-long kickoff session and were given instruction manuals, calendars and pedometers to track their progress. They also received phone calls and newsletters to encourage them to continue. This seemed to work, with the average exerciser reporting 142 minutes of additional exercise per week.
Can people with memory loss stick with an exercise program without this kind of direct support from healthcare professionals? Dr. Baker thinks so, even though people diagnosed with MCI may not be able to structure an exercise program and track progress. “To increase the chance that an exercise program will be successful for a patient with MCI, the family or friends must get involved as well,” she says. “Someone else has to take responsibility for providing the necessary structure and social support. If a family member or friend is willing to help in this way, then an MCI patient can and will adhere to an exercise program, no matter how strenuous.”
Each of these studies was designed differently, but the message is the same: exercise is good for your brain. More research is needed to confirm these results, investigate why exercise seems to improve memory, and understand what support people with memory loss need to exercise regularly.
Most people can do some sort of exercise, and a well-designed program has few negative side effects. It benefits care partners as well as people with memory loss. A pair of walking shoes costs less than a month’s worth of many prescription medicines. What are we waiting for?