Aerobic Exercise

You may even have tried a fad diet or two, but found
yourself right back where you started.
Perhaps like most Americans you have some extra pounds to
shed. You may even have tried a fad diet or two, but found
yourself right back where you started. The key to weight loss is
regular physical activity. And surprisingly, you don't have to
give up eating or make the gym your second home to see longterm,
positive effects.
Your body needs a certain amount of energy to maintain basic
functions such as breathing, blood circulation and digestion.
The energy required to keep your organs functioning is
referred to as the resting or basal metabolic rate.
Any time you are active, additional energy is required. It
is obtained from glycogen and fat stored in the blood, liver,and
muscles. The key to losing weight is to draw on the fat rather
than on the carbohydrate reserves.
Which of the two energy sources you use depends on the
intensity and duration of your activity. The higher the
intensity, the more your body will pull from the stored
carbohydrates. The lower the intensity, the more your body will
rely on fat as its fuel.
Aerobic exercise is most effective for weight loss. Whenyou
perform aerobic activities you repeatedly contract largemuscle
groups such as your legs and arms. Walking,
running,swimming，dancing，and jumping are all forms of
aerobicactivity．
Surprisingly，if your aerobic activity is low to
moderatelyintense and of long duration，you will burn more fat
than if youhad participated in a short burst of high—intensity
exercise．Inshort，a brisk 30-mInute walk wilI burn fat while a
100'yardsprint will burn glycogen．

词汇引擎
①digestion／n.消化力
②metabolic／adj．代谢作用的，新陈代谢的
③glycogen／n．肝糖，糖原质
④duration／n．持续时间
⑤carbohydrate／n．碳水化合物
参考译文
有氧运动

也许和大多数美国人一样，你也需要减去一些多余的体重。你可能尝试
过一两种 ……