①Can exercise during childhood protect you against memory loss many years later? Exercise early in life seems to have lifelong benefits(好处) for the brain, in rats at least.
②"This is an animal study, but it shows that physical activity at a young age is very important — not just good for your body, but for the mind during ageing," says Martin of the University of Toronto, Canada. "In humans, it may put off the appearance of Alzheimer's (阿兹海默症）symptoms, possibly to the point of stopping them. "
③Martinˈs team divided 80 young male rats into two groups, and placed running wheels in the cages of one group for six weeks. Around four months later — when the rats had reached middle age — the team taught all the rats to connect an electric shock with being in a specific box. When placed in the box, they froze with fear.
④Two weeks later, the team tested the rats in three situations: exactly the same box in the same room, the same box in a different room , and a completely different box in a different room.
⑤The rats without a running wheel when they were young now froze the same period of time in each of these situations, suggesting they couldn't remember which one was dangerous. But those that had been able to run when they were young froze 40 to 50 percent less in both changed box settings.
⑥"The results suggest the amount of exercise when we're young, at least for rats, has influence on brain and health — in the form of better memories — when we're older," says Arthur Kramer of Northeastern University in Boston, who has found that, in humans, exercise improves the growth of new brain cells(细胞).
⑦____.
