Moderate over strenuous exercise better for brain

New research shows that women who engage in greater amounts of strenuous physical activity throughout life show poorer performance on cognitive tests that are predictive of Alzheimer's disease and dementia.

"Our findings suggest that while moderate activity protects brain function and may improve cognition over the long term, strenuous activity may increase a woman's risk of developing cognitive impairment or dementia in later life," says Dr. Mary Tierney, director of our geriatric research unit.

This is the first study to examine the link between intensity of long-term physical activity in women between high school and menopause and to find effects on cognition later in life.

"We know that exercise intensity can affect hormone levels," says Dr. Tierney, whose team specifically examined the association in women because strenuous activity is known to affect their estrogen levels.

It's possible that the reduction of estrogen in premenopausal women as a result of greater amounts of strenuous activity over a prolonged period of time may counteract the beneficial effects of that activity on brain functioning.

Some research has shown it may be possible to produce similar levels of exercise capacity with shorter bursts of strenuous aerobic activity as compared to high volume endurance training.