Effect of physical activity on salivary chromogranin A and heart rate recovery after exercise

抄録

  This study examined the relationship between heart rate（HR）recovery and change in salivary chromogranin A levels after physiologically severe stress（Borg’s scale : above 17）in active and hypoactive subjects. Fifteen（14 males, 1 female）physical education students participated and were divided into two groups based on their sport frequency. Saliva was collected before exercise, immediately after cycling exercise and following 2 min of recovery after exercise, and was analyzed commercially using solid phase enzyme immunoassay. Regression analysis of the initial phase of HR recovery showed that the active group exhibited a significantly steeper slope than the hypoactive group（p<0.05）. Salivary chromogranin A concentration was significantly increased after cycling exercise compared with the level at rest（p<0.05）, and the amount at 2 min after exercise had almost returned to the resting level. In particular, the magnitude of the increase after exercise tended to be greater in active than hypoactive subjects, however, there was no statically significant difference in salivary CgA output in both groups. Correlation was seen between the steeper slope of HR recovery and the change percent of salivary chromogranin A output decrement for the first 2 min after exercise（p<0.05）. These results suggested that salivary chromogranin A could be an indicator of short-term change in the activity of the cardiac autonomic nervous system, and that physical activity has a positive effect on post-exercise HR and the subsequent release of humoral components such as chromogranin A via alterations in the cardiac autonomic nervous system.