来自医学博士Eric J. Olson的回答。
 
越来越多的研究显示使用电子设备，如电脑、电视、手机或者电子游戏，特别是在睡觉前使用电子设备，与大人与小孩睡得晚以及睡得少关系密切。

对于这种联系，有很多可能的解释。人们有可能会把之前用于睡眠的时间用于使用电子设备，或者使用电子设备替代了做有利于睡眠的身体活动。另一种可能是由于电子设备会增加生理和心理的刺激，从而使人难以入睡。

很多研究者相信，晚上暴露于电子设备产生的光线会干扰褪黑素——一种帮助控制自然睡眠觉醒周期的荷尔蒙的产生。不过也有可能是那些本身有睡眠障碍的人更倾向于在睡前使用电子设备。显然，这是一个值得更进一步研究的问题。

在此期间， 如果您担心电子设备对您的睡眠有影响，请关注您的睡眠卫生。例如，养成规律的睡眠作息以及在睡前避免来自如电视或者电脑的光线和噪音的刺激。 如果您在床上使用手机或者平板电脑，调暗屏幕亮度并与屏幕保持14英寸（36厘米）远的距离可能有助于减少睡眠被干扰的风险。

中文翻译：Kseniya
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来自医学博士Donald Hensrud的回答。
 
可能会。最近有研究提出睡眠太少与体重增加间存在关联，认为每天睡眠不足五小时或睡眠过多超过九小时会增加体重增长的可能性。

一项研究表明，男性周期性的睡眠缺失会使其更偏爱于高卡路里食物，也增加了对高卡路里食物的总摄入量。有另外一项研究发现，相对于每晚睡七小时的女性来说，女性如果每晚睡眠时间不足六小时或者超过九小时会更有可能增重11英镑（5公斤）。还有些其他研究发现在儿童与青少年中也有类似的现象。

有一种解释说，睡眠太少会影响调节饥饿的两种激素――饥饿激素与瘦素的分泌，从而刺激人的食欲。另外一个促进因素可能是睡眠缺失会导致人体的疲劳进而导致日常锻炼减少。

所以，现在您又有了一个睡个好觉的理由了。

中文翻译：小江
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来自医学博士Timothy Morgenthaler的回答。
 
您需要的睡眠时间长短取决于多种因素，特别是您的年龄。不同年龄段的参考时间为:

年龄组             每天的推荐睡眠量
婴儿               晚上9-10小时，外加至少3小时的小睡
幼儿               晚上9-10小时，外加2-3小时的小睡
学龄儿童          9-11小时
成年人             7-8小时
 
除了年龄，其他因素也会对您需要的睡眠时间有影响。例如:

• 怀孕。在怀孕早期，女性身体的变化会需要更多的睡眠。
• 衰老。老年人需要的睡眠时间和年轻人一样多。然而，随着年龄的增长，睡眠模式可能会发生变化。老年人比年轻人睡眠浅，睡眠时间也短。这可能会导致他们需要在床上花费更多时间来获得足够的睡眠，或者更容易在白天打盹。
• 缺觉。如果您睡眠不足，就需要更多的睡眠。
• 睡眠质量。如果您的睡眠经常被打断或中断，您就无法得到高质量的睡眠。睡眠的质量和数量一样重要。

尽管有些人声称自己每晚只睡几小时就够了，但研究表明，晚上经常睡眠很少的人在复杂的脑力劳动上表现不如那些每晚接近7个小时睡眠的人。一些针对成年人的研究也显示，每晚睡眠时间少于或远多于7小时的人死亡率较高。
 
如果您白天经常犯困，甚至在得到充足的高质量睡眠后仍然如此，请咨询您的医生。医生可以识别潜在的原因，并帮助您在晚上睡得更好。
 
中文翻译：栀子花开
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来自医学博士Timothy Morgenthaler的回答。
 
Antihistamines can cause drowsiness, which might help you fall asleep for a few nights — but routine use of antihistamines for insomnia isn't recommended.

Antihistamines induce drowsiness by working against histamine, a chemical produced by the central nervous system. In fact, most over-the-counter sleep aids contain antihistamines. These products are intended to be used for only two to three nights at a time, however, such as when stress, travel or other disruptions keep you awake.

Tolerance to the sedative effects of antihistamines can develop quickly. As a result, the longer you take them, the less likely they are to make you sleepy. Side effects might include daytime drowsiness, dry mouth and dizziness. Also, diphenhydramine and doxylamine — sedating antihistamines often found in over-the-counter sleep aids — aren't recommended for people who have certain conditions, such as closed-angle glaucoma, asthma, chronic obstructive pulmonary disease or severe liver disease. Keep in mind that most sleep aids aren't recommended for women who are pregnant or breast-feeding.

If you're struggling with chronic insomnia, don't rely on antihistamines or other over-the-counter sleep aids for a good night's sleep. Start with lifestyle changes instead:
 

• Follow a regular sleep schedule.
• Avoid caffeine and daytime naps.
• Include physical activity in your daily routine.
• Manage stress.

If you continue to have trouble falling or staying asleep, consult your doctor. In addition to lifestyle changes, your doctor might recommend ways to make your sleeping environment more conducive to sleep or suggest behavior therapy to help you learn new sleep habits. In some cases, short-term use of prescription sleep aids might be recommended as well.
 
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来自医学博士Lowell Dale的回答。
 
三手烟通常被认为是因吸烟而残留在室内各种物体表面的尼古丁和其他化学物质。这些残留物可与室内常见污染物发生反应产生有毒混合物。三手烟的有毒混合物中含有致癌物质，对暴露于其中的非吸烟者，尤其是儿童，有潜在的健康危害。

研究表明，停止吸烟后很长时间，三手烟依然会附着在头发、皮肤、衣服、家具、窗帘、墙壁、床上用品、地毯、灰尘、车辆和其他表面上。婴儿、儿童和不吸烟的成年人吸入、摄入或接触含有三手烟的物质时，可能会面临与烟草有关的健康问题。“三手烟”是一个相对较新的概念，研究人员仍在研究其可能的危险。

三手烟残留物在物体表面“日积月累”，而且无法用一般的清洁方式将其清除。室内通风、开窗、使用风扇或空调、或限制在家庭特定区域吸烟均无法消除三手烟。相比之下，二手烟是接触了香烟等烟草制品在空气中燃烧时产生的烟雾和其他漂浮在空气中的产物。

保护非吸烟者免受三手烟危害的唯一方法是创造一个无烟环境，无论是您的私人住宅或汽车，还是酒店和餐馆这样的公共场所。

中文翻译：栀子花开
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来自医学博士 James M. Steckelberg的回答。
 
There currently isn't enough evidence to recommend avoiding use of products that contain triclosan — an ingredient added to certain soaps, cosmetics, clothing, cookware, furniture and toys to reduce or prevent bacterial contamination. Recent studies, however, have raised questions about whether triclosan might be hazardous to human health.

Research has shown that triclosan:

• Alters hormone regulation in animals
• Might contribute to the development of antibiotic-resistant germs
• Might be harmful to the immune system

When you use a product containing triclosan, you can absorb a small amount through your skin or mouth. A 2008 study, which was designed to assess exposure to triclosan in a representative sample of U.S. children and adults, found triclosan in the urine of nearly 75 percent of those tested.

Triclosan isn't an essential ingredient in many products. While triclosan added to toothpaste has been shown to help prevent gingivitis, there's no evidence that antibacterial soaps and body washes containing triclosan provide any extra benefits, according to the Food and Drug Administration.

If you're concerned about triclosan, look for products that don't list triclosan in their ingredients.
 
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来自医学博士、哲学博士 James A. Levine的回答。
 
Researchers have linked sitting for long periods of time with a number of health concerns, including obesity and metabolic syndrome — a cluster of conditions that includes increased blood pressure, high blood sugar, excess body fat around the waist and abnormal cholesterol levels.

Too much sitting also seems to increase the risk of death from cardiovascular disease and cancer.

One recent study compared adults who spent less than two hours a day in front of the TV or other screen-based entertainment with those who logged more than four hours a day of recreational screen time. Those with greater screen time had:

A nearly 50 percent increased risk of death from any cause
About a 125 percent increased risk of events associated with cardiovascular disease, such as chest pain (angina) or heart attack

The increased risk was separate from other traditional risk factors for cardiovascular disease, such as smoking or high blood pressure.

Sitting in front of the TV isn't the only concern. Any extended sitting — such as behind a desk at work or behind the wheel — can be harmful. What's more, spending a few hours a week at the gym or otherwise engaged in moderate or vigorous activity doesn't seem to significantly offset the risk.

Rather, the solution seems to be less sitting and more moving overall. You might start by simply standing rather than sitting whenever you have the chance.

For example:

Stand while talking on the phone or eating lunch.
If you work at a desk for long periods of time, try a standing desk — or improvise with a high table or counter.

Better yet, think about ways to walk while you work:

Walk laps with your colleagues rather than gathering in a conference room for meetings.
Position your work surface above a treadmill — with a computer screen and keyboard on a stand or a specialized treadmill-ready vertical desk — so that you can be in motion throughout the day.

The impact of movement — even leisurely movement — can be profound. For starters, you'll burn more calories. This might lead to weight loss and increased energy.

Even better, the muscle activity needed for standing and other movement seems to trigger important processes related to the breakdown of fats and sugars within the body. When you sit, these processes stall — and your health risks increase. When you're standing or actively moving, you kick the processes back into action.
 
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来自医学博士Timothy J. Moynihan的回答。
 
手机和癌症之间的可能联系是有争议的。多年来关于手机和癌症的研究产生了相互矛盾的结果。目前，对于使用手机造成的癌症风险尚没有达成共识。

手机和癌症引起关注似乎是脑部肿瘤的发展与使用手机有关。一些研究显示脑瘤发生率自1970年代以来略有增加，但是手机在1970年代尚未使用。相反，这个微妙的增长更有可能与其他因素有关，比如医疗保健的获得便利性和诊断成像技术的提升。

那么，研究人员已经了解了哪些手机和癌症的信息呢？这里有各种研究的概述：
 
在一项对超过42万手机用户随访20余年的研究中，研究人员发现没有证据表明手机和脑肿瘤之间存在联系。
 
另一项研究发现一种与手机和癌症之间有联系的唾液腺。然而,只有少数受试者患有恶性肿瘤。

另一项最近的研究表明，那些手机重度使用的用户可能会增加患神经胶质瘤的风险——一个特定类型的脑肿瘤，但没有增加所有脑瘤的风险。

经评估几项研究后表明，与手机可能有关联的神经胶质瘤和良性脑瘤称为听神经瘤，世界卫生组织当中的一员--国际癌症研究机构认为手机辐射是否有致癌性证据尚有限。因此，该组织认为射频电磁场是可能致癌的。

不过，这些最近的一系列研究不能反映全部情况。通常一个新的致癌剂，如烟草，需要通过很多年的使用研究才能观察到癌症发病率的增加。在这一点上，有可能由于时间太短，以至于我们无法将癌症发病率的增加直接其归因于手机的使用。

底线？现在，没有人知道手机是否能致癌的。虽然仍在进行长期研究，但到目前为止，仍没有令人信服的证据表明使用手机会增加癌症的风险。如果您担心手机和癌症之间可能存在联系，可以考虑限制手机的使用；或者使用扬声器或免提设备；也可以将手机天线的地方，通常是在手机里面，远离您的头部。

中文翻译：小江
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来自医学博士Donald Hensrud的回答。
 
Brown fat, also called brown adipose tissue, is a special type of body fat that is turned on, or activated, when you get cold. Brown fat produces heat to help maintain your body temperature in cold conditions.

Brown fat has generated interest among doctors and researchers for some time because it appears to be able to use regular body fat as fuel. And equally promising, it looks as if exercise may stimulate hormones that activate brown fat.

Researchers are looking at whether brown fat's calorie-burning properties can be harnessed for weight loss. It's too soon to know whether these efforts will pay off. In the meantime, be sure to include physical activity in your weight management plans.
 
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来自医学博士Richard D. Hurt的回答。
 
If you're considering buying an air purifier, you have a multitude of choices. But if you want an air purifier that will eliminate cigarette smoke, you're out of luck. Most air purifiers, also called air cleaners, are not designed to remove gaseous pollutants, which are a major component of cigarette smoke.

Mechanical air filters, such as high-efficiency particulate air (HEPA) filters, and electronic air cleaners, such as ionizers, target particles, but tobacco smoke particles are designed to be small enough to be inhaled into the outer reaches of the lungs and, thus, are not trapped by such devices.

Other air cleaners generate ozone, which is actually a lung irritant. At levels that don't exceed public health standards, ozone has little ability to remove air contaminants such as cigarette smoke.

The best way to protect nonsmokers from secondhand smoke is to not allow smoking in your home. If you smoke, this is another good reason to stop.
 
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