The Major Components of Human Energy Balance During Chronic ??-Adrenergic Blockade

Abstract

The authors compare the major components of energy balance--dietary food intake, resting metabolic rate, and physical energy expenditure--in patients receiving beta-blocking medications and healthy controls. The authors recruited subjects who were receiving beta-blocking agents (n = 22) from local hospitals and clinics. Twenty-two healthy controls were matched to each patient based on age, weight, and gender. Resting metabolic rates were determined using indirect calorimetry. Three-day dietary intakes and physical activity assessments were analyzed. There were no between-group differences in calories ingested or self-reported physical activity patterns. However, resting metabolic rates were lower in the beta-blocked subjects (beta-blocked = 1,541 +/- 464 kcals/day; controls = 1,817 +/- 426 kcals/day; P < 0.05). beta-adrenergic blockade causes a reduction in resting metabolic rate. Therefore, beta-blocked individuals should increase physical activity, decrease dietary intake, or both to maintain daily energy balance and prevent weight gain that accompanies a reduction in metabolic rate.