Clarence DeMar would train for races by running to and from his job in Boston, up to 14 miles a day. His hard work paid off. He won the 1911 Boston Marathon and competed in the next year’s Olympics.

But at the time, many people and medical experts thought prolonged (持续很久的) exercise was dangerous. A doctor, detecting a heart murmur (杂音), warned DeMar to quit the sport.

DeMar proved them all wrong—both during his lifetime and after—in ways that helped change people’s minds about the benefits of exercise.

He became one of the most noticeable distance runners of his day, competing in two more Olympics and winning the Boston Marathon a record seven times between 1911 and 1930. He kept winning races well into his 40s. The press called him “Mr. DeMarathon”.

After he died of cancer at age 70, two Boston-area experts took a look at his heart. What they found were different from all those terrifying warnings. Not only was DeMar’s heart in good shape, but his arteries(动脉) were also two to three times the size of a typical person’s — reducing the risk of a fatal blockage. As for that heart murmur the doctor warned DeMar about? Experts say, “We now know that highly trained athletes often have a heart murmur, and it’s normal.”

The study, published in the New England Journal of Medicine in 1961, made the front page of The Boston Globe. “It was one of those first studies that taught us that the human body can really handle, very healthfully, lots and lots of exercise,” said Dr. Aaron Baggish, a professor at the University of Lausanne in Switzerland and the former medical director of the Boston Marathon.

The popularity of running exploded in the decades after DeMar’s death, as further research backed that up. It’s now well-established that regular exercise makes us healthier and prolongs our lives.

The current national guidelines recommend at least two and a half to five hours of moderate exercise like walking each week, or an hour and fifteen minutes to two and a half hours of vigorous activity like running—and research suggests more is generally better.

Recently, according to drug company Novo Nordisk, the US Food and Drug Administration (FDA) approved(批准)Wegovy for children who are 12 and over. This weight loss drug has been shown to-encourage weight loss in-people struggling with obesity(肥胖), and this approval smooths the way for teenagers tousle the drug as part of a weight loss way as well.

Teenagers that have a BMI(体重指数)in the top 5％ of their age group will become eligible for a once-a-week use of the drug to go along with a meal plan for reduced calorie intake as well as an exercise plan.

In June 2021, the drug was approved by the FDA for people aged 18 and up with obesity to use, Now, it will be available for teenagers from age 12 and up.

The teen obesity in the US continues to rise, affecting teens and their family. Now, more than ever, we need new choices to support teens. This FDA approval offers an additional tool to deal with this serious and long-lasting disease.

However, many experts have made it clear that while the drug can be a helpful additional tool, it should not be looked at as a cure-all medicine and neither should a weight loss drug.

Tom Sanders, Professor Emeritus of Nutrition and Dietetics at King’s College London shared, “While drugs like this may prove useful in the short term for achieving rapid weight loss in serious obesity, they are not a cure-all medicine for preventing or treating less serious degrees of obesity; public health measures that encourage behavioral changes such as regular physical activity and balanced diets are still needed. It is rather like the situation we are in with the vaccine(疫苗)-we still need to stick with public health measures and should not depend too heavily on medicines. ”

Brushing your teeth effectively lowers your chances of getting a host of chronic diseases, as well as keeping your teeth and gums (牙龈) healthy. But the majority of us are doing it wrong.

In Sweden, one study found as few as one in 10 people practice the best brushing technique. The British health insurer Bupa found that almost half of respondents did not know how to brush their teeth properly in a survey of 2,000 people in the UK.

So what exactly are most of us getting wrong, and how can we change our routine to make sure we brush our teeth effectively? Here’s how to properly brush your teeth, according to experts.

“Lots of patients understand that what they need to do is remove food remains,” says Josefine Hirschfeld, associate professor and specialist in restorative dentistry at the University of Birmingham in the UK. “That is only partially true. It’s much more important to remove bacteria from the teeth.” These bacteria and other microorganisms grow inside everyone’s mouth, and form a sticky biofilm commonly known as dental plaque (牙菌斑). It is made up of around 700 different species of bacteria, the second-greatest diversity in the human body after the gut, as well as a host of fungi and viruses. “They are living in the sticky film stuck to the teeth and also to the soft tissues,” says Hirschfeld. “This sticky film can't be easily rinsed off — it really needs to be manually cleaned.”

The most important place to remove it from is not in fact the teeth, but the gum. This is where microbes are best able to sink the gum tissue and do damage to teeth. In fact, “brushing your teeth” is something of a misnomer. “Think of brushing your gum, rather than the teeth themselves,” says Hirschfeld. “The teeth will then be brushed automatically.”

Brushing too hard, especially with a firmer-bristled brush, can cause injury to the gums. Small tears in the soft tissue caused by overzealous brushing are an opportunity for bacteria to enter the bloodstream. And grating the brush’s bristles over the enamel can wear tiny grooves in the tooth, which add up to significant erosion over time.