It has long been accepted that exercise cuts the risk of heart disease, and recent studies suggest a raft of more general benefits, such as reducing the risk of certain types of cancer and even preventing the onset of Type 2 diabetes. Now it seems that gym junkies can also expect a boost in brainpower, too.
This is not just the vague glow of well-being suggested by sayings such as “a sound mind lives in a healthy body.” John Ratey, a neoropsychiatrist at Harvard Medical School and others are finding that fitness has a long-term influence on a wide range of cognitive abilities. Physical activity seems to be important during childhood, powering the brain through the many changes that help us to mature into adulthood. But it may also play a role as we reach advanced age, with a decline in fitness explaining why some people are more prone to dementia than others.
“It’s a really amazing effect,” says David Raichlen, a biological anthropologist at the University of Arizona in Tucson. Raichlen is investigating whether our ancestors’ athleticism may have accelerated the evolution of their intelligence millions of years ago. Our brains may, in fact, be a byproduct of our brawn.
The link between fitness and the performance of simple cognitive tasks was first suggested by studies in the 1960s, but its importance became more greatly appreciated about 30 years later.
Growing new neurons
In the 1990s, Fred Gage, a geneticist at the Salk Institute in La Jolla, Calif., found that exercise seemed to cultivate the growth of new neurons in mice. At about the same time, Arthur Kramer, a cognitive psychologist at the Beckman Institute for Advanced Science and Technology at the University of Illinois, published a paper in Nature showing that previously sedentary adults who undertook an aerobic fitness plan for six months boosted their performance in cognitive drills that required executive control. That’s the kind of concentration that helps you to switch between different tasks without making mistakes, and it is a key contributor to more general intelligence.