If building cardiac endurance isn't enough motivation for you to do some aerobic exercise, think about this: It also builds your memory.
"Put on your sneakers," says Sue Halpern, author of "Can't Remember What I Forgot: Good News from the Front Lines of Memory Research" (2008, Harmony Books). "We have definite proof that aerobic exercise improves memory.
"Put on your sneakers and walk to the store for that gallon of milk or that loaf of bread. The aerobic requirement is not that stringent."
When interviewed by telephone, Halpern was getting ready for a bike ride through the Vermont countryside near her home, one of her common exercise routines.
"I'm much more religious about it than I was before I began work on the book," she says. "Before when I exercised, I felt the cardiovascular benefits and those relating to my selfimage. Now I know I need to exercise also because it is protective in terms of my memory."
Halpern says that if there is any chance of slowing "normal memory loss and other kinds of memory loss, exercise is it."
For an aerobic benefit, the American Heart Association recommends working at 60 percent to 80 percent of one's maximum heart rate. The guide at americanheart.org suggests a moderate workout, like brisk walking, at the lower range about five times a week for 30 minutes.
To calculate your target heart rate in beats per minute, first subtract your age from 220. That gives your maximum heart rate. Then multiply by 60 percent or 80 percent. People who are in better physical condition have to work harder to raise their heart rate. Discoveries Halpern, a scholar-inresidence at Middlebury College in Vermont, spent more than six years in her mid-40s following the work of leading neurologists and other research scientists for her book. One of the most useful, concrete discoveries from researchers at Columbia University College of Physicians and Surgeons and the Salk Institute in La Jolla, Calif., was that exercise creates new brain cells in the very spot inside the hippocampus where normal memory loss occurs, she says. Normal memory loss is a condition that accompanies growing older, unlike Alzheimer's disease or other brain diseases that cause severe memory impairment, she says. Normal memory loss is forgetting where you put the car keys or forgetting a friend's phone number, while memory loss from disease is forgetting how to drive or forgetting what the telephone is for, she explains. The studies she followed showed that the brain's unraveling caused by Alzheimer's or other dementia may also occur in the hippocampus, but in a different subsection of that region, she says. Normal memory loss is distinct and different from a disease process.
The difference is crucial because people commonly assume that normal memory loss progresses to Alzheimer's or other dementia, but it doesn't, she says. About 14 million people are expected to have Alzheimer's during the next 40 years. About half of people who reach age 85 will have the disease, but half won't, she says. Most people won't live to be 85 years old, she adds. Brain scans in functional magnetic resonance studies show that men and women who exercise more have more neurogenesis, or brain cell production. The participants who exercise also did better on a wide variety of memory tests than those who didn't exercise. Subsequent studies have supported those findings. Still others found lower rates of dementia in people who exercised, Halpern writes in the book. "Exercise was not a cure certainly ... but it did appear to improve memory anyway," she writes. Keep on Learning Exercise spurs neurogenesis and increases the amount of brain- derived neurotrophic factor, which stimulates the birth of new brain cells, helps them grow and become different and then connect and become active, she writes. Those findings are significant for memory, one of the basic tools of human learning, and for acquiring new skills as people get older.
"You can teach an old dog new tricks," Halpern says of a New Mexico connection she found. Researchers from the University of California conducted a study with aging beagles in kennels in New Mexico. The goal was to discover what kinds of diet and environmental enrichments would lead to the dogs learning new tricks. The dogs with more exercise, more social stimulation and an enriched diet performed the best. However, the group of dogs with more social interaction and exercise learned new tricks more quickly than the beagles that ate an enriched diet but received no special exercise or social stimulation, Halpern explains. Those results support what long-term studies of people have shown: Exercise protects the brain, but exercising with a buddy or a group of people probably protects it from age-related memory loss even more, she says. Halpern, who received a doctorate in social sciences from Oxford University in 1985, says she wrote the book to make the research accessible and available. "I wanted to empower people to have the language to have a conversation with their neurologist," she says.
