Morning appears to be the best time of day to exercise for weight management, according to a study published online Sept. 4 in Obesity.
Tongyu Ma, M.B.B.S., Ph.D., from Hong Kong Polytechnic University, and colleagues used data from 5,285 participants in the U.S. National Health and Nutrition Examination Survey (2003 to 2006) to investigate the influence of the diurnal pattern of moderate-to-vigorous physical activity (MVPA) on the association between MVPA and obesity.
The researchers found a strong linear association between MVPA and obesity in the morning group, while a weaker curvilinear association between MVPA and obesity was seen in the midday and evening groups. Among those who met the physical activity guidelines, the adjusted means for body mass index were 25.9 kg/m² in the morning group, 27.6 kg/m² in the midday group, and 27.2 kg/m² in the evening group. For waist circumference, the respective measurements for the three groups were 91.5, 95.8, and 95.0 cm, respectively.
“Morning MVPA could have a positive (i.e., obesity-protective) impact on those who are sedentary for most of the day,” the authors write. “Prospective studies and randomized clinical trials are needed to confirm our findings.”