Objective: To examine the influence of physical activity on body mass index (BMI), waist circumference (W) and body mass changes (DeltaBMI) in middle-aged men, with special regard to moderate-intensity activities.
Design: Longitudinal study of adults who participated in the PRIME Study.
Subjects: A cohort of 8865 men aged 50-59 y, free of coronary heart disease.
Measurements: BMI and W at baseline, body mass changes over a 5 y period. Detailed baseline assessment of net energy expenditure due to physical activity (PAE) in the preceding year, according to category of activity, by means of the MOSPA Questionnaire. PAE was expressed in weekly metabolic equivalent scores (MET h/week).
Results: After adjustment for confounders, the multiple regression analyses indicated that BMI, W and DeltaBMI were inversely associated with PAE spent in getting to work (P<10(-5), <10(-5) and 0.04, respectively) and practice of high-intensity (>or=6 MET) recreational activities (<0.01, <10(-5) and <0.01). Men who regularly spent more than 10 MET h/week in walking or cycling to work had a mean BMI, W and DeltaBMI respectively 0.3 kg/m(2), 1 cm and 0.06 kg/m(2) lower than those who did not expend energy in getting to work. In the subgroup of subjects who did not perform high-intensity activities, the level of recreational PAE was inversely associated with BMI and W but not with subsequent weight-gain.
Conclusion: These findings indicate that, in middle-aged men, physical activities of moderate-intensity, which are probably easier to promote than more vigorous activities and, in particular, a more current daily activity, walking or cycling to work, may have a favourable effect on body fat markers and body mass gain.