Energy expenditure, television viewing and obesity

OBJECTIVE: To measure energy expenditure (EE) of television viewing, sitting, and resting and duration of self-selected television viewing in obese and non-obese men and women. DESIGN: Cross-over randomized study consisting of two separate 24-h stays in a whole-room indirect calorimeter. SUBJECTS : 123 obese and non-obese healthy men and women (age: 38 +/- 9, BMI: 29.4 +/- 7.9) MEASUREMENTS : Rates of energy expenditure during resting (RMR), sitting (EE(sit)) and television viewing (EE(tv)) using indirect calorimetry technique on two separate 24-h stays in a whole-room indirect calorimeter. Physical activities and work of body movements during these periods using a large force platform system located inside the calorimeter. RESULTS: Rates of EE for television viewing, adjusted for differences in body composition were 18% higher than resting metabolic rate (RMR), but similar to rates of other sedentary activities. There were no significant differences between obese and non-obese subjects in metabolic rates during resting, television viewing, and other sedentary activities. Average time of self-selected television viewing was significantly greater in obese than in non-obese subjects and also in women than in men. CONCLUSION: EE rate for television viewing in adults is higher than RMR and similar to other sedentary activities. Obese adults choose television viewing as a form of leisure activity more often than non-obese individuals and as a result they could significantly reduce other forms of physical activities and total daily EE.