Most of us, as we get older, will find that our ability to remember and think dulls a bit. This is considered normal, if annoying. But if the memory loss intensifies, it may become mild cognitive impairment, a medical condition in which the loss of thinking skills grows obvious enough that it becomes worrisome to you and others around you. Mild cognitive impairment is not dementia, but people with the condition are at heightened risk of developing Alzheimer’s disease later.
Scientists have not yet pinpointed the underlying causes of mild cognitive impairment, but there is some evidence that changes in blood flow to the brain can contribute. Blood carries oxygen and nutrients to brain cells and if that stream sputters, so can the vitality of neurons.
But the good news is that exercise can increase brain blood flow, even when exercisers are not moving. In a 2013 neurological study, the brains of physically active older men showed much better blood saturation than those of sedentary men, even when everyone was quietly resting.
So, for the new study, which was published this month in the Journal of Alzheimer’s Disease, researchers at the University of Texas Southwestern Medical Center in Dallas and other institutions asked a group of 70 sedentary men and women, aged 55 or older and diagnosed with mild cognitive impairment, to start moving more.
They divided the volunteers into two groups. One began a program of light stretching and toning exercises, to serve as an active control group. The others started to exercise aerobically, mostly by walking on treadmills at the lab, and then, after a few weeks, outside on their own.
To no one’s surprise, the exercise group was more fit, with higher aerobic capacity, while the stretchers’ endurance had not budged. The aerobic exercise group also showed much less stiffness in their carotid arteries and, in consequence, greater blood flow to and throughout their brains.
Rong Zhang, a neurology professor at UT Southwestern Medical Center, who oversaw the new study, says “it probably takes more time” than a year for the improved brain blood flow to translate into improved cognition.
For now, though, he believes the group’s findings serve as a useful reminder that moving changes minds. “Park farther away” when you shop or commute, he says. “Take the stairs,” and try to get your heart rate up when you exercise. Doing so, he says, may help to protect your lifelong ability to remember and think.