Who do you think are healthier: people born and raised in China, or in the USA? I used to generalize that the average person in China was healthier, mostly from observing Beijing’s lively street life, especially at night. On every street corner you see families, friends and neighbors dance en masse, sing along to classic tunes, and chat away while walking — often backwards. This happens every night in every season — in every city I’ve seen across China. It fits with a well known Chinese proverb 饭后百步走，活到九十九 (take a hundred steps after eating, live to be 99). It’s a wonderful cultural tradition!
So from this wonderful nightly visual, I assumed that Chinese exercise a lot more than Americans — but the actual data doesn’t reflect this casual observation. Not even close, in fact. Only 6 percent of people in China aged 20 to 39 got the proper amount of exercise (the goal is 90 minutes a week of moderate activity). This is far lower than the 26% in Americans aged 19-44. This is also lower than their elders, which confirms the commonly noted observation that elderly Chinese get more exercise than the new generation — just the opposite of America. In China, 10% of people aged 50 to 69 carried out regular exercise, more than the 6% of their children and grandchildren. In the USA, 14% of persons age 65-74 got the recommended exercise, much less than the younger adult 26% rate.
The exercise rates in teens and earlier years are better, mostly because of the built-in school activities, but it tails off quickly in the teen years. With Hong Kong teens, for example, 64% of boys and 40% of the girls achieved the recommended 60 minutes of exercise daily after school. These are higher than in the US, with 37% (45.6% in boys and 27.7% in girls) achieving their daily 60 minutes. With weight, around 7.5% of Chinese children are obese and another 13% overweight; this is still much better than in the USA, where 17% are obese.
Why does activity drop off so quickly for kids in China after middle school? One theory is the incredible amount of studying that Chinese students are accustomed to: children in Shanghai and Hangzhou between grades 4 and 8 spend an average of 150 to 160 minutes doing homework every weekday and more than 200 minutes on weekends. In addition, children spend an average of more than 60 minutes every weekday sitting still and playing on computers, cell phones, tablets and watching TV. That’s an astonishing amount of homework, far more than the amounts I and my American friends and relatives ever had. In the UK, 9 to 11 year olds are expected to get 30 minutes a day of homework, going up to 90-150 minutes a day in high school.
A 2010 China Daily article about this issue agreed that “China’s exam-obsessed education system is taking much of the blame for the deterioration in students’ conditions. “It’s the root reason,” said Sun Yunxiao, deputy director of the China Youth and Children Research Center. “The emphasis is on test scores, not physical well-being. Pupils are being assigned too much homework, leaving no time for exercise.” This brings up an interesting and important topic of debate: what provides the better long term health for a child — a good education or proper exercise habits? After all, many studies show that higher education improves long term health, but studies also show that exercising is crucial for lowering lifetime risks of overall death, heart disease, cancers, diabetes and many other diseases. This imbalance is especially concerning since there is no strong evidence that more homework equals more lifetime success. In fact, many experts feel quite the opposite is true, especially during primary school ages. The American Academy of Pediatrics released a report in 2006 stressing that, “the most valuable and useful character traits that will prepare their children for success arise not from extracurricular or academic commitments but from a firm grounding in parental love, role modeling, and guidance.”
This article is in the current edition of Beijingkids magazine. You can read all my previous Beijingkids articles here. It’s an abridged version of an earlier article I wrote last year for my New York Times column.
Did you know that only ten percent of teenage girls in the USA get enough calcium? Even here in China, the average calcium intake is less than half the recommended amounts. Most infants now have no problems with their calcium, thanks to breast milk and formula. But the second, much more depressing point, is that calcium intake drops dramatically after the toddler years. Girls, especially teens, eat much less dairy than boys, putting them at enormous long term risk for osteoporosis and other disease from low calcium.
What about your teenage children — or what about yourself? Are you getting enough calcium in your diet? To answer this question, we first need to know how much calcium we need per day to stay healthy. According to the US National Institute of Health, children 1-3 years need 700 mg per day, 4-8 years need 1,000 mg, and 9-18 years need the most, at 1,300 mg, to help their rapidly growing bones. Most adults 19-50 years old need a bit less, at 1,000 mg.
I recommend that all parents do a bit of math and see how your kids are faring with calcium, especially your girls. If you’re not sure about the calcium levels in your food, you can use the wonderful online Nutrient Data Laboratory database from the USDA. The best choice for calcium remains dairy products. One cup of whole milk has 246 mg, while low-fat milk has a bit more at 264 mg. Yogurt has a similar amount, and cheese is another excellent choice, as one slice (30 g) of cheese may have 200 mg. If your child hates cow’s milk or is lactose intolerant, at least try to encourage yogurt and cheese. You could also try low-fat or skim chocolate milk, which would be much better than no milk at all! Since breakfast is crucial for a child, a wonderful meal could include yogurt with fresh fruit or berries, plus a slice of cheese on toast.
While dairy is the world’s most common source of calcium, plenty of other foods also have calcium. Kid-friendly healthy choices include calcium-fortified soy milk, orange juice, cereals and granola bars.One 8 ounce cup of fortified orange juice may have 300 mg of calcium. Other non-dairy sources include fortified rice milk, leafy green vegetables (except spinach), and fish such as salmon or sardines. As a last resort, a daily multivitamin may be reasonable for some.
Another helpful task is to completely eliminate all sodas. You don’t have control over your kids at the mall or a friend’s house, but you certainly can be a role model at home and never buy sodas. Ever. Really! I believe that soda is an extremely unhealthy choice at all ages. There’s also some data showing that soda drinkers have lower bone density, but it’s still controversial why that is. Most likely the soda is just replacing healthy calcium drinks such as milk. But there still remain a host of reasons never to drink soda, especially due to its risk of obesity and diabetes. I would much prefer any child drink a calcium fortified orange or apple juice instead of any soda.
What about your daily routine — how much calcium do you get?
It’s cold and flu season yet again, and time to review the simple steps can we all take to avoid these inevitable illnesses. This year’s flu season is a bit more newsworthy than usual as H7N9 bird flu continues to pose a potential threat. But it doesn’t change much how to protect yourselves from this or any other flu, except for a few obvious warnings to avoid touching raw poultry, petting zoos and other basics.
The most common sense preventive measure is hand washing. This is a crucial, simple idea that has been proven for almost 200 years, ever since Dr Lister proved that hand washing with antiseptic dramatically cut down on surgical infections (be thankful you didn’t live back then!). Simple soap and water does the trick — but I also like the alcohol gels as they work quicker and wipe out a much larger percentage of viruses and bacteria than soap.
Another interesting idea is daily gargling, with simple salt water, during the entire winter season. People who gargle up to three times a day have a 40% decrease in respiratory illness and symptoms during the winter. Gargling also is a simple way to help improve sore throat pain and swelling, and it also loosens up mucus.
Another method with good evidence for prevention is a daily supplement of vitamin D, for all ages, during the entire winter season. Daily year-round doses of vitamin D (400 IU for children) are recommended by the American Academy of Pediatrics. Studies show that schoolkids who took a higher dose of vitamin D during flu season had a 42% decrease in influenza infections. I also recommend vitamin D for adults daily here in Beijing, certainly in the winter months and probably all year, as the air pollution cuts down on the needed sunlight that hits our skin and creates vitamin D.
Simply getting a good night’s sleep can also decrease your risk of infections. People who sleep only 6-7 hours a night are three times more likely to get cold symptoms than those who have 8 or more hours of sleep. Proper sleep is crucial for our immune system. Perhaps those of you who feel you “always get colds in Beijing” should check into your sleep patterns!
Many of us try herbal treatments to prevent colds, and you can find good data on effective prevention from the Natural Medicines Database at http://tinyurl.com/bvalz5. Their highest level of support is American ginseng, listed as “possibly safe and effective”. Garlic, ALA, lactobacillus and others have “insufficient evidence”. You will probably be surprised to find that the most commonly used preventive medicines such as echinacea, vitamin C and zinc all are considered “possibly ineffective”.
And of course I must mention the flu vaccine, which is officially indicated for anyone, healthy or sick, after six months of age. It’s not 100% effective for many people, but I feel the benefits far outweigh the risks. Those of you with any contact with newborns and infants under six months of age should seriously consider getting the vaccine for yourselves, as those infants are most vulnerable to the flu, and they are not eligible for the vaccine.
Don’t forget the basic steps for a healthy immune system, via exercising, a good diet full of antioxidants, and not smoking!
This article was initially published in my monthly Beijingkids column.
How much screen time is too much for a child? I’m not worried so much about movie time as I am about the total amount of hours kids spend on TV shows, iPads, laptops and the rest. Most of us instinctively feel that too much of anything is unhealthy, but exactly how bad is screen time? There’s a lot of research with both kids and adults that may stir up some interesting family discussions — hopefully not over a TV dinner. Here’s some scary data to munch over:
- For each additional hour of TV watched on weekends at age 5, the risk of adult obesity increased by 7%.
- In New Zealand, average weeknight TV-viewing between the ages of 5 and 15 years was strongly predictive of adult BMI.
- In a study of 8000 Scottish children, viewing more than 8 hours of TV per week at age 3 was associated with an increased risk of obesity at age 7.
- In 8000 Japanese children, more TV-viewing at age 3 resulted in a higher risk of being overweight at age 6.
- A study of 2343 children aged 9 to 12 years revealed that having a bedroom TV set was a signiﬁcant risk factor for obesity, independent of physical activity.
You’ve probably heard of the American Academy of Pediatric’s official position on total screen time: no child under 2 years old should have any screen time at all, and children of later ages should have a maximum of 2 hours “non-educational” screen time. Again, that includes videos, TV, Youtube and all the rest. How does your family compare? And are you setting a good example as a parent, or do you meet or exceed the American average of 5 hours a day of TV?
There’s a great debate brewing that some screen time is better than others, but no matter what, if your child is sitting in front of a screen, here’s what they’re not doing:
- Asking questions
- Solving problems
- Being creative
- Exercising initiative
- Practicing eye-hand coordination
- Scanning (useful in reading)
- Practicing motor skills
- Thinking critically, logically, and analytically
- Practicing communication skills
- Playing interactive games with other children or adults (helpful for developing patience, self-control cooperation, sportsmanship)
It’s also never a good idea to have a TV in a child’s bedroom. Studies have found increased obesity; rates of smoking later in life; lower test scores; and sleeping problems. Another official policy statement from the American Academy of Pediatrics, called “Children, Adolescents, Obesity, and the Media”, showed strong evidence that TV watching leads to weight gain and all the troubles this causes as adults — diabetes, heart disease, and arthritis, among many other illnesses.
Children who did not adhere to these American Academy of Pediatrics guidelines of less than 2 hours/day of screen time and 11 000 to 13 000 pedometer steps per day were 3 to 4 times more likely to be overweight. Preschool-aged children who ate dinner with their parents, got adequate sleep, and had limited screen-time hours had a 40% lower prevalence of obesity than those exposed to none of these routines. I recommend that parents read the PDF file here, and then have a healthy discussion with your kids!
In closing, I think no matter how dazzled we are by new technology and app claims of “education” and “interaction”, it’s still a passive activity preventing a host of healthier venues of learning, especially independent play time. To quote another AAP doctor, “in today’s ‘achievement culture,’ the best thing you can do for your young child is to give her a chance to have unstructured play—both with you and independently. Children need this in order to figure out how the world works.”
We parents worry about our children getting enough exercise — but what about ourselves? Are we all leading by example and also getting enough exercise? Surveys show that most adults both here in China and in countries like the USA don’t get the recommended 150 minutes a week of moderate exercise or 90 minutes of strong exercise. So for those of us (including myself) who rarely exercise, what can we do to correct this?
New research shows that short, intense exercise may be just as good for your health as longer workouts. Literally a 4 to 7 minute workout is helpful! It’s called high intensity interval training, which basically includes 30 seconds of all-out exercise followed by 10 second breaks, repeated up to 15 minutes. It could be something as simple as squat thrusts, but you can look up “7 minute workout” on my website or Google and see other routines. This 7 minute workout got a lot of publicity a few months ago after being published in a research journal. It’s a shortened version of circuit training, where you rotate your exercises between focused muscle groups, and finishing the entire routine ideally will have covered all muscle groups. Trust me, the next day your muscles will be feeling both that anaerobic achiness and aerobic burn!
One additional benefit of this particular 7 minute cycle is that you don’t need any weights or machines — just your own body, a wall and a chair. You could also repeat this cycle one of two more times for added benefit. It’s important to take those 10 second breaks between reps as it increases the healthy metabolic response. You will definitely need help keeping track of these seconds, and I found a wide collection of apps for smartphones and tablets which can be custom set to beep at the correct intervals. Just search your app store for HIIT, Tabata or “interval timer” and take your pick. One website at 7-minute-workout.net nicely tracks your 7 minute workout.
The key here for all these HIIT routines is is to really push yourself, not take a leisurely pace. In terms of intensity, most of the research papers’ recommendations mention feeling “unpleasant” or “discomforting” after you finish. Many papers also mention something called VO2max, which generally correlates to 100% of your maximum heart rate. The formula for maximum workout heart rate, calculated in a 2001 research paper, is 208 – .7 * age. You should shoot for at least 80% of your maximum heart rate after finishing your routine.
I think this type of evidence-based exercise research is powerful and certainly has altered my usual speech to patients. I previously would always mention the usual recommended minutes of exercise (150 moderate, 90 intense per week) but now can make it even more appealing: 15 minutes, three times a week. But HIIT definitely isn’t for everyone. I don’t think HIIT would appeal to people who already exercise or play sports. And data is still lacking on the long-term benefits and risk reductions from HIIT. I also don’t think that HIIT is appropriate for most kids — they should be getting their recommended 30 minutes of exercise a day from routine gym glasses and after school activities. But for the silent majority of adults who struggle with exercise or always think they don’t have enough time, HIIT routines could be the perfect solution for you.