Section outline

  • General

    Collapse all Expand all

  • 运动运动

    Stroller Moms
    ::阵步妈妈

    These moms are setting a great example for their children by engaging in physical exercise. Adopting a habit of regular physical exercise is one of the most important ways to maintain fitness and good health. From higher self-esteem to a healthier heart, physical exercise can have a positive effect on virtually all aspects of health, including physical, mental, and emotional health. 
    ::这些母亲通过参加身体锻炼为其子女树立了良好的榜样,习惯定期身体锻炼是保持身体健康和健康的最重要方法之一,从更高的自尊到更健康的心脏,身体锻炼可以对包括身体、心理和情感健康在内的几乎所有健康方面产生积极影响。

    What Is Physical Exercise?
    ::什么是身体锻炼?

    Physical exercise is any bodily activity that enhances or maintains physical fitness and overall health and wellness. We generally think of physical exercise as activities that are undertaken for the main purpose of improving physical fitness and health. However, physical activities that are undertaken for other purposes may also count as physical exercise. S crubbing a floor, raking a lawn, or playing active games with young children or a dog are all activities that can have fitness and health benefits, even though they generally are not done mainly for this purpose.
    ::我们一般认为,体育活动主要是为了改善身体健康和健康,但是,为其他目的进行的体育活动也可以算作身体锻炼,摩擦地板、修剪草坪或与幼儿或狗玩活的游戏,都是能给健康和健康带来好处的活动,尽管这些活动一般不是主要为此目的进行的。

    How much physical exercise should people get? In the United States, both the Centers for Disease Control and Prevention and the Surgeon General have recommended that every adult who is able should participate in moderate exercise for a minimum of 30 minutes a day. This might include walking, swimming, and/or household or yard work.
    ::在美国,疾病控制和预防中心和外科总长都建议每个成年人每天至少参加30分钟的中度锻炼,包括步行、游泳和(或)家务或庭院工作。

    Types of Physical Exercise
    ::运动类型

    Physical exercise can be classified into three types, depending on the effects it has on the body: aerobic exercise, anaerobic exercise, and flexibility exercise. Many specific examples of physical exercise (including playing soccer and rock climbing) can be classified as more than one type. 
    ::体育锻炼可以分为三种类型,取决于对身体的影响:有氧锻炼、厌氧锻炼和灵活性锻炼,体育锻炼的许多具体例子(包括踢足球和攀岩)可以分为不止一种类型。

    Aerobic Exercise
    ::有氧运动

    Aerobic exercise is any physical activity in which are used at well below their maximum contraction strength, but for long periods of time. Aerobic exercise uses a relatively high percentage of slow-twitch muscle fibers that consume a large amount of oxygen. The main goal of aerobic exercise is to increase cardiovascular endurance, although it can have many other benefits, including muscle toning. Examples of aerobic exercise include cycling, swimming, brisk walking, jumping rope, rowing, hiking, and tennis.
    ::有氧锻炼是指在远低于其最大收缩强度但长时期使用的任何体育活动。有氧锻炼使用消耗大量氧气的较慢抽动肌肉纤维的比例相对较高。有氧锻炼的主要目的是增加心血管耐力,尽管它可以带来许多其他好处,包括肌肉牵引。有氧锻炼的例子包括自行车、游泳、裸体步行、跳绳、划船、远足和网球。

    Anaerobic Exercise
    ::厌氧运动

    Anaerobic exercise is any physical activity in which muscles are used at close to their maximum contraction strength, but for relatively short periods of time. Anaerobic exercise uses a relatively high percentage of fast-twitch muscle fibers that consume a small amount of oxygen. Goals of anaerobic exercise include building and strengthening muscles, as well as improving strength, balance , and coordination. Examples of anaerobic exercise include push-ups, lunges, sprinting, interval training, resistance training, and weight training (such as biceps curls with a dumbbell, as pictured ).
    ::抗氧锻炼是指肌肉接近其最大收缩强度但时间较短的任何物理活动; 抗氧锻炼使用消耗少量氧气的快速抽动肌肉纤维的比例相对较高; 厌氧锻炼的目标包括建设和加强肌肉,以及提高体力、平衡和协调; 厌氧锻炼的例子包括俯卧撑、肺部、冲刺、间歇训练、抗药训练和体重训练(如图画的那样,有哑铃的比塞螺旋)。

    lesson content

    Pitting the biceps muscle in the upper arm against a heavy weight helps to build and strengthen this muscle.
    ::将上臂的二头肌注射到重量重的部位 有助于培养和强化这种肌肉

    Flexibility Exercise
    ::灵活度活动

    Flexibility exercise is any physical activity that stretches and lengthens muscles. Goals of flexibility exercise include increasing joint flexibility, keeping muscles limber, and improving the range of motion, all of which can reduce the risk of injury. Examples of flexibility exercise include stretching, yoga, and tai chi.
    ::灵活性运动是指任何能拉长肌肉和延长肌肉的体育活动。 灵活性活动的目标包括增加联合灵活性,保持肌肉的肢体,改善运动范围,所有这些都可以降低伤害风险。 灵活性活动的例子包括伸展、瑜伽和泰吉。

    Health Benefits of Physical Exercise
    ::身体运动的健康福利

    Many studies have shown that physical exercise is positively correlated with a diversity of health benefits. Some of these benefits include maintaining physical fitness, losing weight and maintaining a healthy weight, regulating digestive health, building and maintaining healthy bone density, increasing muscle strength, improving joint mobility, strengthening the immune system , boosting cognitive ability, and promoting psychological well-being. Some studies have also found a significant positive correlation between exercise and both quality of life and life expectancy. People who participate in moderate to high levels of physical activity have been shown to have lower mortality rates than people of the same ages who are not physically active. The years of life gained with different amounts of physical activity are shown in the graph .
    ::许多研究显示,身体锻炼与各种健康福利有正相关关系,其中一些福利包括保持身体健康、减肥和保持健康体重、调节消化健康、建立和维持健康的骨头密度、提高肌肉强度、改善联合行动、加强免疫系统、提高认知能力以及促进心理健康,一些研究还发现,身体锻炼与生活质量和预期寿命之间有显著的正相关关系,参加中度至高度体育活动的人的死亡率低于不从事体力活动的同龄人。

    lesson content

    The U.S. Department of Health and Human Services (HHS) recommends that adults aged 18 to 64 engage in regular aerobic physical activity for 2.5 hours at moderate intensity (1.25 hours at vigorous intensity) each week. Moderate activities are those during which a person could talk but not sing. Vigorous activities are those during which a person could say only a few words without stopping for breath. When people exercise at 50 percent of the HHS guidelines, they gain an average of 1.5 years of life. Exercising at 100 percent of the HHS guidelines results in a gain of almost four years of life. The gain in life expectancy starts to level off at about 300 percent of the HHS guidelines.
    ::美国卫生与公众服务部(HHS)建议,18至64岁的成年人每周在中等强度(强力强度为1.25小时)下,定期参加2.5小时的有氧体育活动,时间为2.5小时,时间为2.5小时;活动温和,时间为一个人可以说话但不会唱歌的活动;活动激烈,时间仅能说几句话而不停止呼吸的活动;在50%的HHS准则下进行锻炼时,平均寿命为1.5年;100%的HHS准则使几乎4年的寿命增加;预期寿命增加开始达到大约300年的HHS准则。

    The underlying physiological mechanisms explaining why exercise has these positive health benefits are not completely understood. However, developing research suggests that many of the benefits of exercise may come about because of the role of as endocrine organs . Contracting muscles release called myokines , which promote tissue repair and the growth of new tissue. Myokines also have anti-inflammatory effects, which, in turn, reduce the risk of developing inflammatory diseases. Exercise also reduces levels of cortisol, the adrenal cortex stress hormone that may cause many health problems — both physical and mental — at sustained high levels.
    ::解释为什么锻炼具有这些积极健康好处的基本生理机制没有完全理解,但是,研究的发展表明,锻炼的许多好处可能是由于内分泌器官的作用而产生,捆绑肌肉释放了叫作促进组织修补和新组织生长的肌瘤,子还具有抗炎作用,这反过来又降低了发炎性疾病的风险,并降低了肾上腺皮激素的水平,肾上腺皮激素可能会在高水平上造成许多健康问题,包括身心问题。

    Cardiovascular Benefits of Physical Exercise
    ::运动对心血管的益处

    The beneficial effects of exercise on the are well documented. Physical inactivity has been identified as a risk factor for the of coronary artery disease. There is also a direct correlation between physical inactivity and mortality. Physical exercise, in contrast, has been demonstrated to reduce several risk factors for cardiovascular disease, including hypertension (high pressure), “bad” cholesterol (low-density lipoproteins), high total cholesterol, and excess body weight. Physical exercise has also been shown to increase “good” cholesterol (high-density lipoproteins), insulin sensitivity, the mechanical efficiency of the heart, and exercise tolerance, which is the ability to perform physical activity without undue stress and fatigue.
    ::锻炼对心血管病的有益影响有据可查,身体无活动被确定为冠状动脉疾病的一个风险因素,身体无活动与死亡之间也有直接关系,而身体运动则证明可以减少心血管疾病的若干风险因素,包括高血压(高压)、“坏”胆固醇(低密度脂蛋白)、高胆固醇(高胆固醇)和体重过重,身体锻炼也表明“好”胆固醇(高密度脂质脂质素)、胰岛素敏感性、心脏机械效率以及锻炼耐耐力(即无不当压力和疲劳地进行体力活动的能力)。

    Cognitive Benefits of Physical Exercise
    ::运动的认知利益

    Physical exercise has been shown to help protect people from developing neurodegenerative disorders, such as dementia. A  30-year study of almost 2,400 men found that those who exercised regularly had a 59 percent reduction in dementia when compared with those who did not exercise. Similarly, a review of cognitive enrichment therapies for the elderly found that physical activity — in particular, aerobic exercise — can enhance the cognitive function of older adults. Anecdotal evidence suggests that frequent exercise may even help reverse alcohol-induced brain damage. There are several possible reasons why exercise is so beneficial for the brain. Physical exercise:
    ::对近2 400名男性进行的一项30年研究发现,与那些没有参加运动的男性相比,定期参加运动的人患痴呆症的人数减少了59%。同样,对老年人认知丰富疗法的审查发现,体育活动,特别是有氧锻炼,可以加强老年人的认知功能。

    • increases blood flow and oxygen availability to the brain
      ::增加血液流动 增加大脑氧气供应
    • increases growth factors that promote new brain and new neuronal pathways in the brain
      ::增加增长因素,促进大脑中新的大脑和新的神经系统路径
    • increases levels of neurotransmitters (such as serotonin), which increase memory retention, information processing, and cognition
      ::神经传送器(如血清素)增加,增加记忆保留、信息处理和认知

    Mental Health Benefits of Physical Exercise
    ::身体锻体的心理健康福利

    Numerous studies suggest that regular aerobic exercise works as well as pharmaceutical antidepressants in treating mild-to-moderate depression. A possible reason for this effect is that exercise increases the biosynthesis of at least three neurochemicals that may act as euphoriants. The euphoric effect of exercise is well known. Distance runners may refer to it as “runner’s high,” and people who participate in crew (as in the photo ) may refer to it as “rower’s high.” Because of these effects, health care providers often promote the use of aerobic exercise as a treatment for depression.
    ::许多研究表明,常规有氧锻炼在治疗轻度至中度抑郁症方面以及药物抗抑郁药的作用是正常的。 产生这种效果的一个可能的原因是,这种锻炼增加了至少三种神经化学物的生物合成作用,这些神经化学物可以起到兴奋剂的作用。 锻炼的令人欣喜的效果是众所周知的。 远距离跑者可能称它为“赛跑者高 ” , 参加乘员的人(如照片中的人)可能称它为“驾驶者高 ” 。 由于这些影响,医疗保健提供者常常提倡使用有氧锻炼作为抑郁症的治疗手段。

    This crew team is competing for the U.S. Army in the lightweight division of the world championships in 2003. They are clearly exerting themselves — and no doubt increasing their euphoriant neurochemicals in the process.
    ::2003年世界锦标赛的轻量级赛分赛中, 这支船员队正在与美国陆军竞争。 他们显然在努力,

    Additional mental health benefits of physical exercise include reducing stress, improving body image, and promoting positive self-esteem. Conversely, there is evidence to suggest that being sedentary is associated with increased risk of anxiety.
    ::身体锻炼的其他心理健康好处包括减少压力、改善身体形象和促进积极的自尊。 相反,有证据表明,定居与焦虑风险增加有关。

    Sleep Benefits of Physical Exercise
    ::身体运动的睡眠福利

    A recent review of published scientific research suggests that exercise generally improves sleep for most people, and helps sleep disorders, such as insomnia. Exercise is the most recommended alternative to sleeping pills for people with insomnia. For sleep benefits, the optimum time to exercise may be four  to eight  hours before bedtime, although exercise at any time of day seems to be beneficial. The only possible exception is heavy exercise undertaken shortly before bedtime, which may actually interfere with sleep.
    ::最近对已公布的科学研究进行的审查表明,锻炼通常可以改善大多数人的睡眠,有助于睡眠失常,例如失眠。对于失眠者来说,锻炼是最推荐的替代安眠药的替代方法。对于睡眠福利而言,最好的锻炼时间可能是在睡觉前4至8小时,尽管在任何时间锻炼似乎都是有益的。唯一可能的例外是在睡觉前不久进行繁重的锻炼,这可能实际上干扰睡眠。

    Other Benefits of Physical Exercise
    ::运动的其他好处

    Some studies suggest that physical activity may benefit the immune system. For example, moderate excise has been found to be associated with a decreased incidence of upper respiratory tract infections. Evidence from many studies has found a correlation between physical exercise and reduced death rates from , specifically breast cancer and colon cancer. Physical exercise has also been shown to reduce the risk of type 2 diabetes and obesity .
    ::一些研究表明,身体活动可能有益于免疫系统,例如,发现中度切除与上呼吸道感染的发病率下降有关,许多研究的证据表明,身体锻炼与特别是乳腺癌和结肠癌的死亡率下降之间存在关联,身体锻炼也证明可以降低2型糖尿病和肥胖症的风险。

    Variation in Responses to Physical Exercise
    ::体力锻炼反应变化情况

    Not everyone benefits equally from physical exercise. When participating in aerobic exercise, most people will have a moderate increase in their endurance, but some people will as much as double their endurance. S ome people, on the other hand, will show little or no increase in endurance from aerobic exercise. Genetic differences in slow-twitch and fast-twitch skeletal muscle fibers may play a role in these different results. People with more slow-twitch fibers may be able to develop greater endurance, because these muscle fibers have more capillaries, , and myoglobin than fast-twitch fibers. As a result, slow-twitch fibers can carry more oxygen and sustain aerobic activity for a longer period of time than fast-twitch fibers. Studies show that endurance athletes (like the marathoner pictured ) generally do tend to have a higher proportion of slow-twitch fibers than other people.
    ::并非每个人都能平等地从身体锻炼中获益。 当参加有氧锻炼时,大多数人的耐力会适度增加,但有些人的耐力会提高一倍。另一方面,有些人的耐力不会增加或不会增加。 慢抽搐和快速抽动骨骼肌肉纤维的遗传差异在这些不同的结果中可能起到一定的作用。 较慢抽动纤维的人可能能够发展出更大的耐力,因为这些肌肉纤维比快抽纤维有更多的毛细,而肌蛋白质比快速抽动纤维多。 结果,慢抽动纤维可以携带更多的氧,比快速抽动纤维更长时间地保持有氧活动。 研究表明,耐力运动员(像马拉松画的那样)通常比其他人有更高比例的慢抽动纤维。

    lesson content

    This winning marathoner is likely to have a relatively high proportion of slow-twitch muscle fibers that increase his endurance.
    ::这名获胜的马拉松运动员的慢动肌肉纤维比例可能相对较高,这增加了他的耐力。

    There is also great variation in individual responses to muscle building as a result of anaerobic exercise. Some people have a much greater capacity to increase muscle size and strength, whereas other people never develop large muscles, no matter how much they exercise them. People who have more fast-twitch than slow-twitch muscle fibers may be able to develop bigger, stronger muscles, because fast-twitch muscle fibers contribute more to muscle strength and have greater potential to increase in mass. Evidence suggests that athletes who excel at power activities (such as throwing and jumping) tend to have a higher proportion of fast-twitch fibers than do endurance athletes.
    ::由于厌氧锻炼,对肌肉建设的个别反应也有很大差异。 有些人有更大的能力增加肌肉体积和体力,而另一些人则从未开发过大肌肉,不管它们锻炼多少。 与慢抽动肌肉纤维相比,快速抽动的肌肉纤维比慢抽动的肌肉纤维更能发展出更大、更强的肌肉,因为快速抽动的肌肉纤维对肌肉强度的贡献更大,并且有更大的大规模增长潜力。 有证据表明,擅长权力活动的运动员(如投掷和跳跃)往往拥有比耐力运动员更高的快速抽动纤维比例。

    Can You “Overdose” on Physical Exercise?
    ::身体锻炼能“过量”吗?

    Is it possible to exercise too much? Can too much exercise be harmful? Evidence suggests that some adverse effects may occur if exercise is extremely intense and the body is not given proper rest between exercise sessions. A thletes who train for multiple marathons have been shown to develop scarring of the heart and heart rhythm abnormalities. Doing too much exercise without prior conditioning also increases the risk of injuries to muscles and . Damage to muscles due to overexertion is often seen in new military recruits (see photo ). Too much exercise in females may cause amenorrhea, which is a cessation of menstrual periods. When this occurs, it generally indicates that a woman is pushing her body too hard.
    ::锻炼可能太过分吗? 太多锻炼可能有害吗? 有证据表明,如果锻炼极为紧张,身体在锻炼间隔期间得不到适当的休息,可能会发生某些不利影响;参加多次马拉松训练的运动员显示,他们患上了心脏伤疤和心脏节奏异常;没有事先条件的锻炼过多,也增加了肌肉受伤的风险;新兵经常看到过度施用对肌肉的伤害(见照片)。女性的锻炼过多可能导致月经期的停止,通常表明女性在身体上推得太用力。

    lesson content

    New military recruits may suffer muscle damage from overexertion of unconditioned muscles. The drill instructor pictured here (in orange shirt) is doing his best to encourage these marine recruits to expend their maximum effort.
    ::新兵可能因过度施压而肌肉受损。 这里的钻孔教练(橙色衬衣)正在尽力鼓励这些新兵尽最大努力。

    Many people develop delayed onset muscle soreness (DOMS), which is pain or discomfort in muscles that is felt one to three days after exercising, and generally subsides two or three days later. DOMS was once thought to be caused by the buildup of lactic acid in the muscles. Lactic acid is a product of in muscle tissues . However, lactic acid disperses fairly rapidly, so it is unlikely to explain pain experienced several days after exercise. The current theory is that DOMS is caused by tiny tears in muscle fibers, which occur when muscles are used at too high a level of intensity.
    ::许多人发育迟发性肌肉疼痛(DOMS),即锻炼1至3天后感到的肌肉疼痛或不适,一般在2至3天后消退。DOMS曾经被认为是肌肉中积聚了乳酸造成的。Lactic酸是肌肉组织中的产物。但是,Lactic酸传播得很快,因此不可能解释锻炼数天后所经历的痛苦。目前的理论是,DOMS是由肌肉纤维中的微眼泪造成的,而肌肉的强度太高时会发生。

    Feature: My Human Body
    ::特质:我的人体

    Most people know that exercise is important for good health, and it’s easy to find endless advice about exercise programs and fitness plans. What is not so easy to find is the motivation to start exercising — and to stick with it. This is  the main reason why so many people fail to get regular exercise. Practical concerns like a busy schedule and bad weather can certainly make exercising more of a challenge, but the biggest barriers to adopting a regular exercise routine are mental. If you want to exercise but find yourself making excuses or getting discouraged and giving up, here are some tips that may help you get started and stay moving:
    ::大多数人都知道锻炼对健康很重要,而且很容易找到关于锻炼计划和健身计划的无休止的建议。 最容易找到的不是开始锻炼的动机 — — 并坚持下去。 这是许多人未能定期锻炼的主要原因。 忙碌的日程和恶劣天气等实际问题当然会让锻炼更具挑战性,但接受常规锻炼的最大障碍是精神上的障碍。 如果您想锻炼,但发现自己在制造借口或感到沮丧并放弃,这里有一些可以帮助你开始和保持运动的提示:

    • Avoid an all-or-nothing point of view. Don’t think you need to spend hours sweating at the gym or training for a marathon to get healthy. Even a little bit of exercise is better than nothing at all. Start out with ten or 15 minutes of moderate activity each day. Taking a walk around your neighborhood is a great way to begin! From there,  gradually increase the amount of time until you are exercising to at least 30 minutes a day, five days a week.
      ::避免一无所有或一无所有的观点。 不要认为你需要花几个小时在健身房里汗汗或训练马拉松才能健康。 即使一点点锻炼比什么都好。 每天从10或15分钟的温和活动开始。 在邻居周围散步是一个很好的开始方式。 从那里开始,逐渐增加时间,直到你每天至少锻炼30分钟,每周5天。
    • Be kind to yourself, and reinforce positive behaviors with rewards. Don’t be down on yourself because you are overweight or out of shape. Don’t beat yourself up because of a supposed lack of willpower. Instead, look at any past failures as opportunities to learn and do better. When you do achieve even small exercise goals, treat yourself to something special. Did you just complete your first workout? Reward yourself with a relaxing bath or other treat.
      ::对自己好,用奖励来强化积极的行为。 不要因为体重过重或体形失常而自欺欺人。 不要因为缺乏意志力而自欺欺人。 相反,只要把过去的失败看成是学习和做得更好的机会。 当你确实实现了哪怕是小的锻炼目标时,你就会把自己看成是特殊的东西。你刚刚完成了第一次锻炼吗?用一个放松的浴室或其他的治疗来补偿自己。
    • Don’t make excuses for not exercising. Common complaints include being too busy or tired or not athletic enough. Such excuses are not valid reasons to avoid exercising, and they will sabotage any plans to improve your fitness. If you can’t find a 30-minute period to work out, try to find ten  minutes, three times a day. If you’re feeling tired, know that exercise can actually reduce fatigue and boost your energy level. If you feel clumsy and uncoordinated, remind yourself that you don’t need to be athletic to take a walk or engage in vigorous house or yard work.
      ::不要为不锻炼找借口。 常见的抱怨包括过于忙碌、疲劳或不够运动。 这些借口不是避免锻炼的正当理由,它们会破坏任何改善身体健康的计划。 如果你找不到30分钟的锻炼时间,请尝试找到10分钟,每天3次。 如果你感到疲劳,那么知道这项锻炼实际上可以减少疲劳,提高你的能量水平。 如果觉得笨拙和不协调,请提醒自己不必运动去散步或参加激烈的家庭或院子工作。
    • Find an activity that you truly enjoy doing. Don’t think you have to lift weights or run on a treadmill to exercise your muscles. If you find such activities boring or unpleasant, you won’t stick with them. Any activity that increases your heart rate and uses large muscles can provide a workout, especially if you’re not in the habit of exercising, so find something you like to do. Do you like to dance? Put on some music and dance up a sweat! Do you enjoy gardening? Get out in the yard and dig up some dirt! Still not interested? Try an activity-based video game, such as Wii or Kinect. You may find it so much fun that it doesn’t seem like exercise until you realize you’ve worked up a sweat.
      ::找到一个你真正喜欢的活动。 不要认为你必须举起重量或跑步机来锻炼肌肉。 如果你发现这样的活动乏味或不愉快, 你就不会坚持。 任何提高心率和使用大肌肉的活动都可以提供锻炼, 尤其是如果你没有锻炼的习惯, 所以找到你喜欢做的事。 你喜欢跳舞吗? 装上一些音乐, 跳起汗来! 你是否喜欢园艺? 到院子里去挖些泥土! 还是不感兴趣? 尝试一场以活动为基础的电子游戏, 比如Wii 或 Kinect 。 你可能会发现它是如此有趣,直到你意识到自己在出汗之前,它看起来不像锻炼运动。
    • Make yourself accountable. Tell friends and family members that you’re going to start exercising. You’ll be letting them — as well as yourself — down if you don’t follow through. Some people find that keeping an exercise log to track their progress is a good way to be accountable and stick to an exercise program. Perhaps the best way to keep at it is to find an exercise partner. If you’ve got someone waiting to exercise with you, you will be less likely to make excuses for not exercising.
      ::让自己负起责任。告诉朋友和家人你将要开始锻炼。如果你不坚持到底,你就会让他们——以及你自己——失望。 有些人发现,保持锻炼记录跟踪他们的进展是负责任和坚持锻炼计划的一个好办法。 也许最好的办法就是找到锻炼伙伴。 如果你有人在与你一起锻炼,你就不会为不锻炼找借口了。
    • Add more physical activity to your daily life. You don’t need to follow a structured exercise program to increase your activity level. Do your house or yard work briskly for a workout. Park your car further  than necessary from work or the mall, and walk the extra distance. If you live close enough, leave the car at home and walk to and from your destination. Rather than taking elevators or escalators, walk up and down stairs. When you take breaks at work, take a walk instead of sitting. Every time a commercial comes on while you’re watching TV, take a quick exercise break — run in place or do some curls with hand weights.
      ::在日常生活中增加更多的体育活动。 您不需要遵循结构化的锻炼程序来提高活动水平。 您的家或院子可以快速地锻炼锻炼。 请在工作或购物中心把车停得比必要的更远的地方停放, 并且走多一点距离。 如果您住得够近, 请离开汽车, 离开汽车, 往返于目的地, 而不是坐电梯或扶梯, 上下楼梯。 当你休息时, 步行而不是坐着。 每次看电视时, 广告都会响起, 快速休息, 运行在原地, 或者做一些手重的卷卷。

    Summary
    ::摘要

    • Physical exercise is any bodily activity that enhances or maintains physical fitness and overall health. Activities such as household chores may count as physical exercise, even if they are not done for their health benefits. Current recommendations for adults are 30 minutes a day of moderate exercise.
      ::体力锻炼是指加强或保持身体健康和整体健康的任何身体活动,如家务等活动可算作身体锻炼,即使没有为健康福利而做,目前对成年人的建议为每天30分钟的温和锻炼。
    • Aerobic exercise is any physical activity that uses muscles at less than their maximum contraction strength, but for long periods of time. This type of exercise uses a relatively high percentage of slow-twitch muscle fibers that consume large amounts of oxygen. Aerobic exercises increase cardiovascular endurance and include cycling and brisk walking.
      ::有氧锻炼是指使用肌肉的物理活动,其收缩强度低于其最大收缩强度,但使用时间较长;这种锻炼使用相当高比例的慢动脉肌肉纤维,消耗大量氧气;有氧锻炼增加心血管耐力,包括循环和快速行走。
    • Anaerobic exercise is any physical activity that uses muscles at close to their maximum contraction strength, but for short periods of time. This type of exercise uses a relatively high percentage of fast -twitch muscle fibers that consume small amounts of oxygen. Anaerobic exercises increase muscle and bone mass and strength, and they include push-ups and sprinting.
      ::抗氧锻炼是指在接近最大收缩强度但短期内使用肌肉的任何体育活动。 这种锻炼使用相当高比例的快速抽动肌肉纤维,消耗少量氧气。 抗氧锻炼会增加肌肉和骨质质量和强度,包括俯卧撑和冲刺。
    • Flexibility exercise is any physical activity that stretches and lengthens muscles, thereby improving range of motion and reducing risk of injury. Examples include stretching and yoga.
      ::灵活性运动是指任何伸展和延展肌肉的体育活动,从而扩大运动范围,减少受伤风险,例如伸展和瑜伽。
    • Many studies have shown that physical exercise is positively correlated with a diversity of physical, mental, and emotional health benefits. Physical exercise also increases quality of life and life expectancy.
      ::许多研究表明,身体锻炼与身体、精神和情感健康的各种好处有着积极的关联,身体锻炼也提高了生活质量和预期寿命。
    • Many of the benefits of exercise may come about because contracting muscles release hormones called myokines, which promote tissue repair and growth and have anti-inflammatory effects.
      ::锻炼的许多好处可能来自于肌肉萎缩释放了叫“近氧”的荷尔蒙,促进组织修复和生长,并产生抗炎效果。
    • Physical exercise can reduce risk factors for cardiovascular disease, including hypertension and excess body weight. Physical exercise can also increase factors associated with cardiovascular health, such as mechanical efficiency of the heart.
      ::身体锻炼可以减少心血管疾病的危险因素,包括高血压和体重超重,身体锻炼也可以增加与心血管健康有关的因素,例如心脏机械效率。
    • Physical exercise has been shown to offer protection from dementia and other cognitive problems, perhaps because it increases blood flow or neurotransmitters in the brain, among other potential effects.
      ::身体锻炼证明可以防止痴呆症和其他认知问题,也许因为它增加了大脑的血液流动或神经传导,以及其他潜在影响。
    • Numerous studies suggest that regular aerobic exercise works as well as pharmaceutical antidepressants in treating mild-to-moderate depression, possibly because it increases synthesis of natural euphoriants in the brain.
      ::许多研究表明,定期有氧锻炼和药物抗抑郁剂在治疗中低度低温抑郁症方面起作用,这可能是因为它增加了大脑中自然兴奋剂的合成。
    • Research shows that physical exercise generally improves sleep for most people and helps sleep disorders, such as insomnia. Other health benefits of physical exercise include better immune system function and reduced risk of type 2 diabetes and obesity.
      ::研究表明,身体锻炼一般会改善大多数人的睡眠,有助于睡眠失调,如失眠,身体锻炼的其他健康好处包括免疫系统功能更好,2型糖尿病和肥胖的风险降低。
    • There is great variation in individual responses to exercise, partly due to genetic differences in proportions of slow-twitch and fast-twitch skeletal muscle fibers. People with more slow-twitch fibers may be able to develop greater endurance from aerobic exercise, whereas people with more fast-twitch fibers may be able to develop greater muscle size and strength from anaerobic exercise.
      ::个人对锻炼的反应差异很大,部分原因是慢动和快动骨骼肌肉纤维比例的遗传差异。 较慢动纤维的人也许能够从有氧锻炼中产生更大的耐力,而较快动纤维的人则能够从厌氧锻炼中产生更大的肌肉体积和强度。
    • Some adverse effects may occur if exercise is extremely intense and the body is not given proper rest between exercise sessions. Many people who overwork their muscles develop delayed onset muscle soreness (DOMS), which may be caused by tiny tears in muscle fibers.
      ::如果锻炼极为紧张,身体在锻炼间隔期间得不到适当的休息,可能会产生一些不利影响。 许多肌肉过度劳累的人会产生迟发性肌肉疼痛(DOMS ) , 这可能是肌肉纤维微小的眼泪造成的。

    Review
    ::回顾

    1. How do we define physical exercise?
    ::1. 我们如何界定体育锻炼的定义?

    2. What are current recommendations for physical exercise for adults?
    ::2. 目前对成人体育锻炼有何建议?

    3. Describe and give examples of aerobic exercise. 
    ::3. 描述并举例说明有氧锻炼。

    4. How does anaerobic exercise differ from aerobic exercise? What are some examples of exercises that are anaerobic?
    ::4. 无氧锻炼与有氧锻炼有何不同?哪些是无氧锻炼的实例?

    5. Define flexibility exercise, and state its benefits. What are two examples of flexibility exercises?
    ::5. 界定灵活做法的定义并说明其好处:灵活做法的两个例子是什么?

    6. In general, how does physical exercise affect health, quality of life, and longevity?
    ::6. 一般而言,身体锻炼如何影响健康、生活质量和寿命?

    7. What mechanism may  underlie many of the general health benefits of physical exercise?
    ::7. 身体锻炼的许多一般健康利益可以依据什么机制?

    8. Relate physical exercise to cardiovascular disease risk.
    ::8. 身体锻炼与心血管疾病风险相关。

    9. What may explain the positive benefits of physical exercise on cognition?
    ::9. 如何解释身体锻炼对认知的积极好处?

    10. How does physical exercise compare with antidepressant drugs in the treatment of depression?
    ::10. 在治疗抑郁时,身体锻炼如何与抗抑郁药物相比?

    11. Identify several other health benefits of physical exercise.
    ::11. 确定身体锻炼的其他几项健康惠益。

    12. Explain how genetics may influence the way individuals respond to physical exercise.
    ::12. 解释遗传学如何影响个人对身体锻炼的反应方式。

    13. Can too much physical exercise be harmful?
    ::13. 太多身体锻炼是否有害?

    14. Lifting very heavy weights for a short period of time is likely to... 
    ::14. 在很短的时间内抬起非常沉重的重量很可能会...

    a. use a relatively high percentage of fast-twitch muscle fibers
    ::a. 使用较高百分比的快速抽动肌肉纤维

    b. use a relatively high percentage of slow-twitch muscle fibers
    ::b. 使用相当高比例的慢抽动肌肉纤维

    c. be an aerobic exercise
    ::c. 作有氧锻炼

    d. use a large amount of oxygen
    ::d. 使用大量氧气

     

    15. Walking quickly for an extended period of time is likely to...
    ::15. 长时期快速行走很可能会...

    a. use a relatively high percentage of fast-twitch muscle fibers
    ::a. 使用较高百分比的快速抽动肌肉纤维

    b. use a relatively high percentage of slow-twitch muscle fibers
    ::b. 使用相当高比例的慢抽动肌肉纤维

    c. use muscles at close to their maximum contraction
    ::c. 在接近最大收缩时使用肌肉

    d. cause the muscles to use only a small amount of oxygen
    ::d. 导致肌肉只使用少量氧气

    Explore More
    ::探索更多

    Watch this fascinating TED talk to learn why some people find it more difficult to exercise than others, and what they can do to make it easier for them to adopt an exercise routine.
    ::观察TED这个令人着迷的演讲, 了解为什么有些人觉得比其他人更难锻炼, 以及他们能做些什么来使他们更容易 采取锻炼常规。