Background: Little is known about the effects that climatic conditions, especially extreme heat, have on physical activity (PA) levels. The aim of this 2-year cohort analysis undertaken in the Arabian Gulf region was to assess changes in objectively-assessed PA as a result of changes in climatic conditions.
Methods: A total of 2088 adults (1390 men and 698 women) from many regions of the world were enrolled in a community health program in Qatar, were included in this study. For 2 years participants recorded daily step count using an Omron HJ-720 ITC pedometer. Daily climate parameters included temperature, relative humidity and other conditions.
Results: From linear mixed model analysis it was evident that higher average temperature and humidity, and the Wet bulb Globe Temperature (WbGT), resulted in a reduction of the number of steps taken per day. Analysis of interaction effects also revealed that the effects of heat stress were equivalent across gender, age, and the region participants came from according to a World Health Organization classification scheme.
Conclusions: Increased temperature and humidity are associated with a reduction in the number of steps taken per day. Community-based PA programs in hot hot/humid climates should consider novel approaches to increase PA levels.
Keywords: heat stress index; humidity; step count; temperature.