Abstract
[Purpose] To clarify the characteristics of arm exercise, which easily increases breathlessness in patients with cardiorespiratory disease, the relationship between vagal activity and cardiorespiratory function according to muscle group use was examined. [Subjects] The subjects were 11 healthy young males. [Methods] Using an ergometer, arm and leg exercise was performed at a low-intensity, Karvonen 30%. The time constants of the beat-by-beat heart rate decay for the first 30 s (T30) and the coefficient of variance of heart rate were calcuated, and the respiratory rate was measured. [Result] A positive correlation was found between T30 and heart rate coefficient of variance, and T30 and respiratory rate in the arm exercise. No relationship was found in the leg exercise. [Conclusion] The results of this study suggest that respiratory rate and heart strain will increase in persons with slow heart rate decay in the arm exercise. This is thought to be due to rapid withdrawal of vagal outflow and an early increase in sympathetic nerve activity.
