• A large portion of activity inequality is attributable to a gender step gap whereby women walk disproportionately fewer steps than men everyday. The gender step gap is evident in almost every country and widest in high-obesity countries.
• Walkable built environments encourage more walking and physical activity, which reduces activity inequality and obesity prevalence.

Results:

• There is “activity inequality” worldwide, in which there is a wide gap between those who are very physically active and walk a lot versus those who aren’t physically active and don’t walk a lot. Activity inequality is associated with reduced physical activity and higher obesity levels.
• Although walking more is associated with lower obesity, activity inequality is a better predictor of obesity prevalence than the average number of steps taken.
• Globally, women walk less than men every day. This gender step gap is widest in high-obesity countries. The prevalence of obesity also increases more rapidly for females than males as activity decreases, which puts women at higher risk of obesity-related health problems. In countries with high activity inequality, females are disproportionately less physically active compared to males.
• Aspects of the built environment, such as walkability, may mitigate gender differences in activity and overall activity inequality. More walkable cities are associated with increased activity levels.
• In more walkable cities, activity is higher on weekdays during morning and evening commute times and at lunchtime on weekend afternoons. This indicates that walkable environments increase physical activity during both work and leisure time.

Implications:

• Policies and interventions should be designed to close the gender step gap and promote greater physical activity and walking among women worldwide. Differences in cultural gender roles and aspects of the built environment contribute to the gender step gap, but an important and unexamined cause of the gender step gap is gendered perceptions of safety: Threats and realities of sexual harassment and violence against women limit whether, when, and how much women walk.

Methods:

• The researchers used smartphone data to measure physical activity for 717,527 people in 111 countries worldwide over 68 million days.

Althoff, T.; Hicks, J.; King, A.; Delp, S.; and Leskovec, J. (2017). Large-scale physical activity data reveal worldwide inequality. Nature.