Background:
Sleep duration disorders impact the quality of life and energy expenditure in workers. However, there is a lack of understanding about the relationship between sleep duration and energy expenditure at work among motorcycle taxi drivers.

Aims:
To analyze the relationship between sleep duration and energy expenditure at work in motorcycle taxi drivers.

Settings and Design:
A cross-sectional study was conducted with 296 male motorcycle taxi drivers from Rio Branco City, western Brazilian Amazon. Methods and Material: The motorcycle taxi driver reported the number of hours daily spent sleeping on a typical day during the week. Uncorrected and corrected energy expenditures of motorcycle taxi drivers during the working day were calculated according to the 2011 Physical Activity Compendium. The metabolic equivalent (MET) was corrected for the basal metabolic rate using the equation proposed by Harris and Benedict.

Statistical Analysis:
The relationship between sleep duration and energy expenditure at work was analyzed using fractional polynomial regression.

Results:
The mean sleep duration in hours was 7.4 (SD: 1.4). There was a relationship between sleep duration and corrected energy expenditure at work, with a first-degree logarithmic transformation. The nonlinear relationship between sleep duration and uncorrected energy expenditure at work was a fractional polynomial with a power of -0.5 for the first degree.

Conclusions:
The results suggest a nonlinear relationship between sleep duration and energy expenditure at work among motorcycle taxi drivers. Motorcycle taxi drivers with short sleep durations had high energy expenditures at work.