Plasma and lymphocyte cyclic nucleotide response to acute exercise in healthy adults

Plasma and lymphocytic cyclic nucleotide levels were assayed in 11 (5 male, 6 female) healthy normal adults before and after bicycle ergometry exercise. Lymphocytosis after exercise was observed. Plasma cAMP level was increased by almost 2 fold after exercise. However, plasma cGMP level was not affected. On the contrary, lymphocytic cAMP level was decreased by one third while cGMP level was halved. There were linear regression relationships between maximum heart rate and % difference in lymphocyte count and lymphocytic cyclic nucleotide levels pre- and post-exercise. Our findings demonstrate that higher cardiac output leads to increased lymphocytosis but decreased lymphocytic cyclic nucleotide levels.