Physical fitness is today’s hot topic. And everywhere you turn you hear something new. But is it all true？
The more you sweat， the more fat you burn. This myth has encouraged people to work out in extreme heat or wear layers of clothes or rubber or plastic weight-loss suits in the hope of sweating fat off. Unfortunately， it’s water they’re losing， not fat.
Fat burns when it is used as a fuel source for exercise， which doesn’t happen initially①. When you first begin to exercise， you burn carbohydrates or sugars. It takes about 20 minutes of easy to moderate aerobic activity before the transition② from burning sugars to fat begins. (Aerobic exercise is any rhythmic and continuous activity that uses oxygen and large muscle masses of the body， such as the arms and legs. Examples are bicycle riding， jumping rope， walking， jogging， aerobic dance， and swimming.) So， to burn the flab， plan on working out at least 40 minutes.
No pain， no gain. Many people tend to overdo their exercise programs looking for quick results. Doing so， however， may prove to be your downfall by resulting in injury or sore muscles. Your best bet is to start any exercise program slowly and gradually increase the workout. It’s better people start out with 15 minutes of stretching， 30 to 40 minutes of walking or walking/jogging， and end with 10 more minutes of stretching. This gives people a good beginning without the pain or injury.
Electric stimulation. Electric stimulation may help make a muscle contract and tone it slightly， but this technique can’t take the place of exercise， and it certainly won’t help you lose weight. If you want to decrease body fat， you must do aerobic exercises.
Exercise increases appetite. This is true for hard or intense exercise that lasts for 60 minutes or longer. Moderate exercise that is less than 60 minutes， however， will probably reduce your appetite for one to two hours.
Exercise always lowers blood sugar. Generally， exercise will lower blood sugar and it’s best to prepare for exercise by eating before you start out. If your blood-sugar level is above 250 mg/dl， however， exercise could make it rise even higher.
You can get fit in 10 minutes a week. This and similar claims are common， but untrue. There are no shortcuts to getting fit. Becoming fit takes work and the general rule is 20 minutes of aerobic activity three times a week. Consistency③ is the key. If you miss a day or two， don’t try to compensate④ by doing double duty—you open yourself up to injury.
If you stop working out， your muscles will turn to fat. If you decrease your activity and continue to eat the same or more， you may gain back that spare tire that you worked so hard to lose. It’s not， however， because your muscles turned to fat. Muscles may atrophy or lose their tone， but they won’t turn to fat. Muscle is muscle and fat is fat.
① initiallyadv. 最初；开头
② transitionn. 过渡；过渡时期； 【音】临时转调；转调过渡段
③ consistencyn. 一贯；一致；符合；协调； (液体等的)浓度；粘稠；坚硬；坚硬度
④ compensatevt. 补偿，赔偿；酬报[(+for)] vi. 补偿，赔偿；抵消[(+for)]
锻炼的秘密
保健是当今的热门话题。无论你走到哪里，你都听到新奇的事情。但是，那都是正确的吗？
流汗越多，消耗的脂肪越多。 这个错误的观点鼓励人们在极热的环境下运动，或者穿好几层衣服或者穿橡胶或塑料减肥服，希望通过流汗将脂肪排出。不幸的是，排出去的是水而不是脂肪。
作为一种燃料能源，脂肪只是在运动时才消耗。而且并不是在运动初始阶段就能奏效。当你要开始运动时，你消耗的是碳水化合物，或者糖类。平缓进行有氧运动大约20分钟才会使你由消耗糖类向消耗脂肪过渡。(有氧运动就是有节奏的、持续的活动。它需要耗氧并且锻炼像手臂和腿部的大块肌肉。例如骑自行车、跳绳、步行、慢跑、跳舞和游泳)。所以说，要消耗脂肪，至少要运动40分钟。
不劳则无获。有些人倾向过度锻炼达到更快的效果。然而这样做可能造成伤害或引起肌肉疼痛。最佳的方式就是缓慢地开始锻炼，然后逐渐增加运动量。人们开始锻炼时，最好先用一刻钟的时间进行伸展运动，然后进行30到40分钟的步行或步行加慢跑，最后以10分钟的伸展运动结束。以这样的方式开始运动就会有个良好的开端，不会感到疼痛，也不会受到伤害。
用电疗代替锻炼。 电疗可能有助于肌肉收缩，稍微变得结实，但是这种疗法不能代替锻炼，也不能帮助你减肥。如果你想减少脂肪，你必须要做有氧运动。
锻炼增加食欲。对于持续进行了1个小时或者更长时间的剧烈运动的人来说确实如此。然而，不到1个小时的平缓运动很可能在1至2个小时内减少你的食欲。
锻炼将会降低血糖。通常锻炼总会降低血糖，在开始锻炼前你最好先吃点东西做准备。然而，如果你的血糖量高于250毫克/分升，锻炼会使你的血糖量升得更高。
每周10分钟的锻炼，你就能变得健康。 这种说法和类似的观点很普遍，但不正确。健康之路无捷径。要想变得健康需要锻炼。通常的规则是每周进行3次，每次20分钟的有氧运动。坚持是关键。如果你错过了一两
天，不要通过加倍的运动来弥补，这样做你会受到伤害。
如果你停止锻炼，你的肌肉将变成脂肪。 如果你减少运动量，并且继续吃相同或更多的食物，你过去努力锻炼而减去的脂肪很可能会卷土重来。然而，这并不是因为你的肌肉变成了脂肪。肌肉可能萎缩或失去弹性，但是它们不能变成脂肪。肌肉就是肌肉，脂肪就是脂肪。
