Jan. 8 (HealthDay News) -- Exercise appears to help prevent and improve mild cognitive impairment, two new studies show.
Researchers found that people who did moderate physical activity in midlife or later had a reduced risk of mild cognitive impairment and that six months of high-intensity aerobic exercise improved cognitive function in people with mild cognitive impairment.
Mild cognitive impairment is an in-between state between the normal changes in thinking, learning and memory changes that come with age and dementia, one of the studies explained. Up to 15 percent of people with mild cognitive impairment develop dementia each year, compared with 1 percent or 2 percent of the general population.
The first study included 1,324 dementia-free volunteers taking part in the Mayo Clinic Study of Aging. The participants completed a physical exercise questionnaire and were assessed and classified as having normal cognition (1,126) or mild cognitive impairment (198).
Those who said they did moderate exercise -- such as swimming, brisk walking, yoga, aerobics or strength training -- during midlife were 39 percent less likely to have mild cognitive impairment, while those who did moderate exercise later in life were 32 percent less likely to have the condition.
The Mayo team said exercise may guard against mild cognitive impairment through production of nerve-protecting compounds, increased blood flow to the brain, improved development and survival of neurons, and decreased risk of heart and blood vessel diseases.
The second study included 33 adults, average age 70, with mild cognitive impairment. Some were randomly assigned to do high-intensity aerobics for 45 to 60 minutes a day, four days a week. Others were put in a control group that had the same workout schedule, but did stretching exercises and kept their heart rate low.
After six months, the patients who did high-intensity aerobic exercise had improved cognitive function compared to those in the control group. The beneficial effects were more pronounced in women than in men, possibly because the body's use of and production of insulin, glucose and the stress hormone cortisol differed in women and men.
"Aerobic exercise is a cost-effective practice that is associated with numerous physical benefits. The results of this study suggest that exercise also provides a cognitive benefit for some adults with mild cognitive impairment," wrote Laura D. Baker, of the University of Washington School of Medicine and Veterans Affairs Puget Sound Health Care System in Seattle, and colleagues.
The studies appear in the January issue of the Archives of Neurology.
SOURCE: JAMA/Archives journals, news release, Jan. 11, 2010