Increase in atrial natriuretic peptide in response to physical exercise.

Circulating atrial natriuretic peptide (ANP) level was determined during physical exercise to investigate the correlation between changes in ANP level and heart rate increases. Six subjects exercised at a work level of 75% VO2max for 30 min, two also performed two successive exercises at 75% VO2max while two more exercised for longer at 55% VO2max. Plasma ANP levels and heart rate increased in all the exercising subjects. At the end of the exercise, the ANP level fell immediately, suggesting an immediate reduction in ANP secretion by the heart. Pre-exercise values were reached after 30 min. Successive exercises gave the same heart rate related ANP patterns without previous secretory episodes having any effect. These results lead to the conclusion that ANP intervenes in the cardiovascular adjustments to exercise.