A new health study conducted by a team of Stanford University researchers have found that Americans are physically less active than people Living In China, Japan, Spain and UK.

How was the study conducted

The health study, which has been published in the journal Nature, tracked the walking activity of more than 700,000 people from 111 countries using smartphone data. Most smartphones have a built-in sensor called accelerometer that can record steps automatically.

In this case, the researchers took account of the variation in activity in terms of the mean number of steps walked by people daily for an average of 95 days using the Argus activity monitoring app.

Argus activity monitoring app is a free app which can be used to track physical activity as well as other health behaviors.

Researcher Scott Delp, a bioengineering professor, claimed that the study is 1,000 times larger than any other study previously conducted on human movement. He said that there have been big health surveys already done in the past, but the new study provides data from more countries, many more subjects, and tracks people's activity on an ongoing basis.

Delp added that the result of the new Health Study opens the door to new ways of doing science at a much larger scale than ever before.

Key ingredient - Activity inequality

Notably, "activity inequality" was the key ingredient of the study.

Like wealth inequality is the difference between rich and poor, activity inequality is the difference between a country's most and least active person. The more is the level of activity inequality, the higher is the obesity rate.

The health study found that people living in Hong Kong walk an average of 6,880 steps every day (around 6 kilometers or three-and-a-half miles) and are the most active, while people living in Indonesia are the least active accounting for an average of just 3,513 steps per day.

Americans averaged 4,774 steps per day. It is to be noted that the United States and Mexico both had similar average steps, but the former had higher activity inequality and obesity levels.

Interestingly, the research also found that activity inequality was largely driven by gender differences. The gender step gap varied from country to country with negative consequences for women.

In countries with low obesity and low inequality like Japan, men and women had similar physical activity levels. But in countries like the US where there is high inequality, it was women who spend less time being active.

The researchers are expecting that the health study results could be used to design towns and cities that promote greater physical activity.