After undergoing initial assessments of percentage of body fat (% fat), triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and maximal oxygen consumption (VO2Max), a group of 24 paid male fire fighters (mean age, 30.1 +/- 7.7 years) began a mandatory exercise program. The physiological variables mentioned above were assessed once a year for the subsequent 5 years. A repeated-measures multivariate analysis of variance followed by univariate post hoc techniques showed a minimal but statistically significant improvement in % fat (-1.43% +/- 0.66%) and TG (-27.54 +/- 10.44 mg/dl) over the 5-year period. Significant differences in TC, HDL-C, LDL-C, and VO2Max were noted over the years, but their magnitudes were small and no pattern was demonstrated. Each of the 5-year means for TC, LDL-C, % fat, and VO2Max were outside the desirable ranges. We concluded that mandatory exercise programs do not significantly alter the risk factor status or the aerobic fitness levels of fire fighters and that a significant number of the latter demonstrate a higher than average risk for cardiovascular disease.