There’s a clever English language play on words, “assuming makes an ass out of you and me.” As an American expat straddling two cultures, I confess that it’s all too easy to make sweeping generalizations about differences, usually defaulting to my home country. But when it comes to health, I recently had felt that the average Chinese person is healthier than the average American. I was so convinced of this that I wrote an article on my blog asserting this. But after a chorus of criticism from my long term readers plus a rejection letter from my New York Times editor, I was forced to revisit my assumptions with better data. But I couldn’t find much supportive data at all. In fact, I uncovered much which makes me very worried about the future health of China’s children.

My main argument in favor of China’s health had centered around the sensory splendor of Beijing’s lively street life at night. On every street corner and in every park, generations of 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 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). There’s simply nothing like this social nightlife in America, and it’s a wonderful cultural tradition which I deeply wish we had in America. In top cities like enlightened and active San Francisco, there may be a few people walking their pets or jogging after dinner, but otherwise most American sidewalks are empty at night.

So from this wonderful nightly visual, I assumed that Chinese exercise a lot more than Americans. Here’s where the “assuming” part comes in: the statistical data doesn’t reflect this casual observation. Not even close, in fact. A 2008 survey, released by China’s State General Administration of Sport, found that only 6 percent of people aged 20 to 39 got the proper amount of exercise (90 minutes a week). This is far lower than the 26% in Americans aged 19-44 reported in the U.S. Health and Human Services report from 2012. 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.

What accounts for this striking difference in youth, also an ominous trend for China’s future health? One theory is the incredible amount of studying that Chinese students are accustomed to: a recent survey of 7,000 people in Shanghai and Hangzhou showed that children 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.”

My wife and I love to spend our summer nights biking around our nearby hutongs and sometimes join in a dance. It’s one of the most charming traditions we have in China, and I can’t wait for our little Alex to join in the fun. I can only hope that other young people also join in, but the trend is not encouraging.