Objective: To determine the longitudinal relation of change in cardiopulmonary fitness to subsequent change in body weight in a cohort of healthy middle-aged adults.
Design: Prospective cohort study.
Subjects: Participants were 4599 men and 724 women (43 +/- 9 y) receiving at least three medical examinations between 1970 and 1994. Examinations included assessment of cardiorespiratory fitness by maximal exercise tests and measurement of body weight.
Measurements: Change in fitness was calculated as the difference in maximal treadmill time between the first and second examination (mean interval, 1.8 y). Weight change was calculated as the difference in body weight between the first and last examination (mean follow-up, 7.5 y).
Results: There was a small, yet statistically significant weight gain over the follow-up (0.61 +/- 5.29 kg for men and 1.51 +/- 4.67 kg for women; P << 0.001). Estimates from the multiple linear regression modeling show that each 1 min improvement in treadmill time, significantly attenuated weight gain in both men (b = -0.60; P << 0.001) and women (b = -0.60; P << 0.001), respectively. Moreover, each 1 min improvement in treadmill time, reduced the odds of a > or = 5 kg gain by 14% in men (odds ratios (OR)) = 0.86; 95% confidence interval (CI): 0.83-0.89) and by 9% in women (OR = 0.91; 95% CI:0.83-1.00) and the odds of a > or = 10 kg gain by 21% in both men (OR = 0.79;95% CI:0.75-0.84) and women (OR = 0.79;95% CI:0.67-0.93)
Conclusions: Improvements in fitness, appear important in attenuating age-related weight gain in healthy middle-aged adults. Thus, an active life-style should be promoted early and maintained through adulthood to prevent substantial weight gain and obesity with age.