Effects of exercise during the holiday season on changes in body weight, body composition and blood pressure

Background/objectives: Identifying critical periods of greater weight gain could provide useful information to combat the obesity epidemic. We tested whether body weight (BW), body fat percentage (BF%) and blood pressure (BP) changed during the holiday season (thanksgiving to new year's day) and the impact of regular exercise on these parameters. Subjects/methods: A total of 48 males and 100 females (age 18-65 years) with a mean body mass index of 25.1±0.5 kg/m² were evaluated in mid-November (visit 1) and early January (visit 2; across 57±0.5 days). Anthropometric data, BF%, BP and self-reported exercise were recorded. Results: Participants showed significant increases in BW (0.78±0.1 kg, P<0.001, 95% confidence interval (CI): 0.57-0.99), BF% (0.5±0.2%, P=0.007, 95% CI: 0.12-0.77), systolic blood pressure (SBP; 2.3±1.2 mm Hg, P=0.048, 95% CI: 0.01-4.63) and diastolic blood pressure (1.8±0.8 mm Hg, P=0.028, 95% CI: 0.20-3.49). Obese participants (35.2±0.8 kg/m²) showed a greater increase in BF% compared with normal weight participants (21.7±0.2 kg/m ², P<0.05, 95% CI: 0.53-2.37) and a trend vs overweight participants (26.8±0.3 kg/m², P=0.07, 95% CI: -0.18-1.65). Exercise (4.8±0.6 h per week) did not protect against holiday weight gain and was not a significant predictor for changes in BW or BF%. Data are reported as means±s.e. Conclusion: Our participants gained an average of 0.78 kg, which indicates the majority of average annual weight gain (1 kg/y) reported by others may occur during the holiday season. Obese participants are most at risk as they showed the greatest increases in BF%. Initial BW, not exercise, significantly predicted BF% and BW gain.