英语六级阅读练习：保持大脑年轻化

　　Move It

　　Quick whats the No. 1 thing you can do for your brains health? Differential calculus, you say? Chess? Chaos theory? Nope, the best brain sharpener may be sneakers? Yup. Once theyre on your feet, you can pump up your heart rate. The best advice I can give to keep your brain healthy and young is aerobic exercise, says Donald Stuss, PhD, a neuropsychologist and director of the Rotman Research Institute at Baycrest Centre for Geriatric Care in Toronto.

　　differential calculus 微积分;微分学

　　chaos theory 混沌理论

　　pump up 给打气;加速

　　aerobic exercise 有氧运动

　　Mark McDaniel, PhD, professor of psychology at Washington University in St. Louis, agrees, but adds, I would suggest a combined program of aerobics and weight training. Studies show the best outcomes for those engaged in both types of exercise.

　　As we age, our brain cells, called neurons, lose the tree-branch-like connections between them. These connections, or synapses, are essential to thought. Quite literally, over time, our brains lose their heft. Perhaps the most striking brain research today is the strong evidence we now have that exercise may forestall some kinds of mental decline, notes McDaniel. It may even restore memory. Myriad animal studies have shown that, among other brain benefits, aerobic exercise increases capillary development in the brain, meaning more blood supply, more nutrients and a big requirement for brain health more oxygen.

　　forestall v. 垄断;预先阻止

　　mental decline 智力下降

　　The preeminent exercise and brain-health researcher in humans is Arthur Kramer at the University of Illinois at Urbana-Champaign. In a dozen studies over the past few years, with titles such as Aerobic Fitness Reduces Brain Tissue Loss in Aging Humans, Kramer and his colleagues have proved two critical findings: Fit people have sharper brains, and people who are out of shape, but then get into shape, sharpen up their brains. This second finding is vital. Theres no question that working out makes you smarter, and it does so, Kramer notes, at all stages of life. Just as important, exercise staves off heart disease, obesity, diabetes and other maladies that increase the risk of brain problems as we age.

　　preeminent adj. 卓越的

　　a dozen 一打;十二个

　　out of shape 走形;变样

　　sharpen up 使更敏锐;认真思考

　　stave off 避开;延缓