The aim of this study was to develop a sensitive mark-or to predict salutary effects of physical exercise on promotion of health of sedentary workers, Effects of short-term (13 weeks) periodical physical exercise on body weight, cardiovascular physiology, lipid and glucose metabolism, and cardiac autonomic nervous function were determined. Forty-six subjects (24 males and 22 females; 29 sedentary workers, 51 +/- 12.7 years old) completed the program. Two groups of subjects were identified; one with an increase in high frequency (HF) power of heart rate variability, an index of parasympathetic activity, after the program, and the other without an increase in HF power. The former group showed a decrease in heart rate and serum triglyceride level, and a borderline trend toward an increased exercise tolerance after the program. The other group did not show any appreciable changes in the variables studied. Augmentation of HF power of heart rate variability could be a promising index for prediction of salutary effects of periodical physical exercise.