【推荐2】We often take sleep for granted, but not getting enough shut-eye can increase our risk for many serious health issues such as poor mental health, heart problems or even early death.

The ideal bedroom temperature for people to fall asleep is relatively cold — between 17 to 20℃. A drop in our core body temperature is essential for us falling and staying asleep because it stimulates sleepiness.

Obradovich and his colleagues found unusually warm temperatures had the largest effect on people’s bedtime duration by delaying falling asleep. Short sleep durations were the worst during the summertime and among the elderly, probably because they have more difficulty regulating their body temperature. The team also found warmer locations experienced the most sleep loss, suggesting people’s bodies haven’t adapted to their geographic location. Lower income countries are also heavily affected, which Obradovich supposes could be because of a lack of air-conditioning. But he plans to investigate further. Data show global warming also will have the biggest sleep loss in the Middle East, southeast Asia and Australia. By the end of the 21st century, people in the warmest regions are expected to lose another three nights of sleep per year due to higher nighttime temperatures.

Obradovich said his team’s findings could help communities or policymakers better improve the sleep environment for people, such as helping to cool bedrooms more effectively. On an individual level, Robbins, a physician at Harvard Medical School, said people also need to practice generally good sleep behavior. For instance, reducing screen time 15 to 20 minutes before falling asleep as the blue lights from cellphones or computers can work like the sun and throw off our body clock. She suggested meditation (冥想) before bed can significantly help people relax, making it easier for people to fall asleep.

“There’s still belief that ‘I’ll sleep when I’m dead’ kind of attitude towards sleep,” Robbins said. “There’s so much work to be done to improve our collective view of sleep.”

【推荐3】How To Keep Your Tongue Healthy?

Do you know that your tongue is a key part of your oral health?    1    That’s why it’s important to keep your tongue healthy! In this blog post, we will discuss how to keep your tongue healthy and free from disease.

Mouthwash not only removes bacteria from your teeth and gums, but it also helps freshen your breath. One way to use mouthwash is to swish(使嗖嗖地移动) it around in your mouth for a minute or two.    2    

A healthy diet is important for overall health.    3    It can also help prevent heart disease, stroke, and other health problems. In addition to eating a healthy diet, you should also brush your teeth regularly to remove plaque(牙菌斑) and bacteria from your mouth.

Smoking is one of the worst things you can do for your oral health. It increases your risk of developing oral cancer, and it can also cause bad breath and stained teeth.

Green tea has many health benefits. It’s a good source of antioxidants.    4    Green tea contains catechins, which can kill bacteria and prevent plaque from forming on your teeth.

Keeping your tongue healthy should be on your daily to-do list. The tips provided above will help you achieve and maintain a healthy tongue.    5    Start practicing these tips today!

【推荐3】Travel enthusiasts fifty years ago talked about travelling to fascinating places around the world. Today the talk is about going beyond the world and the Earth. The thirst is creating a demand for space travel, giving rise to space tourism.

The space fights are not cheap - each flight into outer space costs about U.S. $20 million. Up till now, it has solely been enjoyed by a few adventurous super-ich men. To reduce the high cost of space travel for the mass market, space travel agencies now have a creative plan to offer suborbital flights, which cost much less. These joyrides will enable the tourists to reach the edge of space, which is more than 62 miles above the Earth, and allow them the experience of a few minutes of weighlessness as they gaze at the Earth below, before they return down to Earth again.

Space tourism is, however, not an environmentally friendly adventure. The black carbon emitted by the spacecraft could either raise temperatures at the poles, causing a melting of the ice or lead to rising temperatures, contributing to global warming. The emission of black carbon also causes the ozone molecules to break apart, contributing to several kilotons of carbon dioxide to the atmosphere.

Looking beyond Earth, an increase in space travel would mean that Man would not only leave his footprint in space but also his waste—space tourism can contribute to pollution of the environment of the outer space. With no current plans for waste disposal, one can only imagine clumps of litter floating around the planets.

Without doubt, space tourism opens up new exciting possibilities. With time, the price of the flights to space would become more reasonable. Increasing commercialization of space travel would also mean that a structure would be put in place for the disposal of space waste. However, with no immediate solution to counter the possible impact on climate changes and the thinning of the ozone layer, space tourism would probably prove to be yet another controversial (有争议的) venture of mankind.