Fatigue and cardiac and endocrine metabolic response to exercise after abdominal surgery

Subjective feeling of fatigue was quantified before and 20 days after elective uncomplicated abdominal surgery in 16 otherwise-healthy patients and compared with changes in heart rate and various hormonal and substrate responses to a 10-minute bicycle exercise (65% of preoperative maximal work capacity) preoperatively and postoperatively. Postoperatively, fatigue increased (p less than 0.001) from 3.0 +/- 0.5 to 5.3 +/- 0.5 arbitrary units (mean +/- SEM). Heart rate, plasma catecholamines, and serum growth hormone, lactate, alanine, and glycerol values always increased, whereas serum insulin values decreased in response to exercise (p less than 0.01). During exercise, only heart rate (p less than 0.01) and lactate (p less than 0.05) values were higher postoperatively compared with preoperatively. Increase in fatigue postoperatively correlated significantly to increase in heart rate (p less than 0.01) and correlated positively, but not significantly, to increase in plasma levels of noradrenaline (p = 0.08), growth hormone (p = 0.09), and alanine (p = 0.08) during exercise, but not to increase in serum lactate values (p greater than 0.8). Thus, after uncomplicated surgery, there was increased fatigue and amplified metabolic and cardiovascular response to a given absolute work load. These findings are similar to those observed during detraining and suggest a therapeutic role of exercise in the treatment of postoperative fatigue.