RESUMO
CONTEXT: Non-exercise physical activity thermogenesis (NEAT) has been shown to differ in obese and non-obese subjects. OBJECTIVE: To explore whether NEAT is determined by the body mass index (BMI) even within the normal range, we hypothesized that the daily walking distance of young doctors in training at a teaching hospital is inversely correlated with the BMI. DESIGN: Prospective, single blind, controlled trial. SETTING: Identical wards of a 400 bed university-based teaching hospital, highly standardized for patient number treated, the severity of disease, the clinical experience of the doctors and their time spent in the institution. INTERVENTION: The walking distance was measured daily by a pedometer over one week and standardized for the setting, workload, and insurance status. MAIN OUTCOME MEASURES: Mean daily walking distance as a measure of NEAT. RESULTS: The mean daily distance walked was 2323+/-627 m with a more than 4-fold difference between the daily maximum of 4310 m and the minimum of 1003 m. There was an inverse correlation of the walking distance with the BMI (Spearman rho=0.750, p=0.02), and with the time spent in the hospital (rho=-0.800, p=0.01), but not with the months of clinical experience, age, gender, number of patients, disease, severity nor with the insurance status of the patients cared for. There was no mean difference between the distance walked in the morning vs. in the afternoon nor was there a trend from Monday through Friday. CONCLUSION: The results of this pilot study indicate that NEAT is related to the BMI in the non-obese stage.
