What defines sedentary behavior?

The definition of sedentary behavior is characterized by energy expenditure of ≤1.5 METs (Metabolic Equivalent of Task) while in a sitting, reclining, or lying posture. This definition focuses on the low energy expenditure associated with these activities, which signifies a lack of physical movement that is required for more active lifestyles.

METs provide a standardized measure that reflects physical activity intensity; specifically, 1 MET is defined as the energy cost of sitting quietly, which typically equates to around 3.5 mL of oxygen consumed per kilogram of body weight per minute. Thus, when activities have energy expenditures of 1.5 METs or lower, they are classified as sedentary behavior, highlighting the crucial distinction between physical inactivity and overall activity levels.

The other options do not accurately capture the essence of sedentary behavior. Although fatigue could be associated with inactivity, it is not a definitive measure for defining sedentary activities. Exercising at a low intensity can still involve movement and energy expenditure above the sedentary threshold. Furthermore, while prolonged inactivity might seem closely related, it is not sufficient alone to define sedentary behavior without addressing the associated energy expenditure.