That sample size is a big deal. As researcher Scott Delp explained to the BBC, the study is about 1,000 times the size of previous research on human movement. “There have been wonderful health surveys done, but our new study provides data from more countries, many more subjects, and tracks people's activity on an ongoing basis,” he said. “This opens the door to new ways of doing science at a much larger scale than we have been able to do before.”
Their findings? The average number of daily steps worldwide, they said, was 4,961. But that number varied widely from country to country. In top-place Hong Kong, for example, survey participants took an average of 6,880 steps a day. In Indonesia, the average was just 3,513, putting it at the bottom of the rankings.
China (where people walk an average of 6,189 steps a day) and Japan (6,010) are also near the top of the list. Spain (5,936) and the United Kingdom (5,444) are above average, too. The United States clocks in at about 4,774 steps a day, a bit below the worldwide average. Some of the most sedentary countries are Saudi Arabia, Malaysia, South Africa and India.
Interestingly, the average number of steps stepped was not correlated to obesity levels in a particular country, at least not directly. A much better predictor was “activity inequality,” which works just like income inequality, but with steps instead of dollars. In places where some people got lots of steps and others got just a tiny amount, obesity levels were higher.
“For instance, Sweden had one of the smallest gaps between activity rich and activity poor … it also had one of the lowest rates of obesity,” researcher Tim Althoff told the BBC. That pattern becomes even more clear when you compare the United States to Mexico. The countries have a similar step average, but Mexico's activity inequality and obesity levels are both much lower.
Another interesting fact: Activity inequality was largely driven by the exercise patterns of men and women. In Japan, men and women got about the same amount of steps, and the country's activity inequality level is low. In places like Saudi Arabia and the United States, women are much less active than men, which leads to much higher “activity inequality.”
“When activity inequality is greatest, women's activity is reduced much more dramatically than men's activity, and thus the negative connections to obesity can affect women more greatly,” Jure Leskovec, also part of the research team, told the BBC.
Unsurprisingly, walkability also played a role. In pedestrian-friendly locations where it's easy to get lots of places on foot … people walked more.