Bright light enhances the efficiency of physical activity in combination with a restrictive diet

Abstract

The purpose of this study was to analyze the effectiveness of measures aimed at correcting obesity in women and including bright light exposure during aerobic exercise combined with a restrictive diet. A one-stage, randomized study involved 80 obese women aged 20 to 58 years. The inclusion criterion for selecting participants for this research was the presence of primary ali mentary-constitutional obesity with body mass index equal to or higher than 30 kg/m 2 . All the wo men were distributed into three groups according to the set of applied treatments. In Group 1, the women were on a restrictive diet; in Group 2, the restrictive diet was accompanied with daily ae robic exercise; in Group 3, women were expos ed to bright light during exercise. Before and after the treatment course (3 weeks), body weight, waist and hip circumferences were measured; fat amount was determined by the impedancemetry method; and oxygen consumption was determined by indirect calorimetry. Women in Group 1 had reduced body weight, waist and hip circumferences, fat mass and oxygen consumption. Similar changes were identified in women of Group 2, but weight loss was greater, and the level of oxygen consumption increased as compared to the baseline. In women of Group 3, weight loss and increased oxygen consumption were more pronounced than in those of Group 2. The number of metabolic equivalents (MET) in women of Group 3 increased to nearly 1, which corresponded to the value of this index that reflected the resting metabolic rate in patients with normal body weight. Thus, exposure to bright full-spectrum light increases energy metabolism and enhances the effectiveness of exercises, despite prolonged food restriction, which is one of the mechanisms to improve the efficiency of obesity correction.