Memory's Best Friend? A Treadmill

How exercise may protect against Alzheimer's

According to the World Health Organization, more than 35 million people worldwide are living with Alzheimer’s disease, and that number is expected to double by 2030. If those figures alone don’t make you run to the gym, here’s something that will.

Recently, researchers at the University of California-Irvine examined adults between the ages of 50 to 85, half of whom had memory deficits and half of whom were mentally healthy. After dividing the group and asking one group to exercise on a stationary bike for six minutes—the other group did nothing—participants provided a saliva sample and then were shown images of animals and nature scenes. An hour later, the groups were given a surprise memory test. All those who exercised, regardless of whether they had cognitive impairments or not, showed improved memory.

“We saw significantly better recall in the exercise group than in the nonexercise group,” says lead study author Sabrina Segal. “This was particularly significant in cognitively impaired participants who almost doubled their recall improvement.”

What gives? In a word: norepinephrine, a brain chemical induced by exercise, which influences memory. This is where the saliva samples come in. The exercise group showed high levels of the enzyme salivary alpha amylase, a biomarker for norepinephrine. In fact, the link was higher in participants who started out with cognitive deficits.

While the connections between norepinephrine, exercise, and memory are still speculative, previous research with drugs that influence norepinephrine levels shows that increasing the brain chemical can improve memory, while blocking it impairs recall. The key for researchers now is to take other factors into account, such as how long the memory benefits last. Still, the work provides new insights into the way a healthy lifestyle yields benefits that go beyond the body and into the mind.


“Even Brief Exercise Can Improve Memory in Older Adults” by Alexandra Sifferlin, http://healthland.time.comTime, 11/27/12