Sometimes, the pace of modern life barely gives you time to stop and rest. It can make getting a good night’s sleep on a regular basis seem like a dream. 【小题1】 Good sleep improves your brain performance, mood, and health.

People often think that sleep is just downtime when a tired brain gets to rest, but that’s wrong. 【小题2】 For example, sleep helps prepare your brain to learn, remember, and create. Besides, certain repair processes occur in the body during sleep. If you don’t get enough sleep, those processes are going to be disturbed (干扰).

【小题3】 One is that adults need less sleep as they get older. This isn’t true. Older adults still need the same amount, but their sleep quality can get worse as they age. Another one is that you can catch up on your days off. However, researchers say that the weekend catch-up sleep doesn’t always help.

Some people have conditions that prevent them from getting enough good quality sleep, no matter how hard they try. These problems are called sleep disorders. The most common sleep disorder is insomnia (失眠症). Insomnia happens when you have repeated difficulty getting to sleep or staying asleep, although you have the time to sleep and a proper sleep environment. 【小题4】 If you’re having trouble sleeping, hearing how important it is may be discouraging. But don’t worry too much. 【小题5】 Cognitive behavioral therapy (CBT) can help many people with insomnia get better sleep. Medicine can also help some people.

Blue light blocking (BLB) glasses are supposed to protect eyes from the effects of short-wave length light from our smartphones, computer screens and LED lights. Given how much time we spend on our devices, using this type of glasses sounds like a smart investment, right?

Elizabeth Esparaz, an eye specialist based in Cleveland, Ohio, says the science that producers share as they promote these glasses can be confusing and doubtful. Blue light is not just about tech devices, and it’s not always bad. “The sun produces much more blue light than human-made devices, and it’s actually advantageous,” says Dr. Esparaz. It helps our mood and sleep-wake cycle. The problem is blue light at night: It prevents the release of melatonin, a substance helping regulate our body and making us sleepy.

So, in theory, wearing BLB glasses should help people who watch movies in bed or read from a tablet at night avoid wakefulness. A review study from the University of Oklahoma that looked at 24 previous studies found that people affected by sleep disorders, jet lag (时差反应) and shift work dropped off to sleep faster after using these glasses. “So to some extent, these glasses are useful to some people,” saysDr. Esparaz. But the effectiveness is not wide and does not extend beyond certain cases.

As for eye strain (疲劳), a condition of the eyes usually caused by a long period of looking at screens, an Australian study showed that those wearing BLB glasses did not experience less eye strain than those using clear glasses. And another review study, also by Australian researchers, found inadequate evidence that BLB glasses could prevent serious eye problems.

“These glasses aren’t going to be harmful,” says Dr. Esparaz. But, she adds, they are maybe not as good as advertised and a lack of standardization in the industry means there’s no way to know if one pair is better than another.

Fats are nutrients in food that the body uses to build cell membranes (细胞膜), nerve tissue, and hormones. 【小题1】. If fats eaten aren’t burned as energy or used as building blocks, they’re stored by the body in fat cells. This is the body’s way of thinking ahead: By saving fat for future use, it plans for times when food might be scarce (缺乏的).

【小题2】, but certain kinds of fat are good for us and are an important part of a healthy diet. Fat gives food flavor and texture, but it’s also high in calories, and eating too much fatty food can cause many health problems. For kids and teens, fast food, fried food, and snacks are a significant source of fat. 【小题3】.

Eating the right kind and amount of fat is an important part of a healthy diet. But many kids eat too much fat, which might lead to unwanted weight gain. 【小题4】.

Besides supplying fuel for the body, fats help the body absorb fat-soluble (脂溶性) vitamins. 【小题5】. They can also help people feel full, so they’re less likely to overeat. Fat is a great source of energy, but has twice the calories in the same amount of carbohydrates or protein. For example, 1 gram of fat provides 9 calories, whereas 1 gram of carbohydrates or protein provides 4 calories.