Prior exercise alters responses to hemorrhage.
Traumatic injuries often occur to individuals while exercising. The author sought to determine whether exercise before injury resulting in hemorrhage would alter cardiovascular, metabolic, and neuroendocrine responses. Fifteen chronically instrumented splenectomized immature female swine were trained to run on a treadmill at 70% of maximum heart rate for 60 min. In six swine, responses to exercise were evaluated and found to return to baseline after 60 min of recovery. Swine were then randomly assigned to exercise (n = 7) or rest (n = 8) followed by hemorrhage of 25 mL/kg for 60 min then observed for an additional 60 min. The decrease in mean arterial pressure (MAP) was less after exercise, 26 +/- 9 mmHg compared with 49 +/- 2 mmHg with rest, with the difference sustained during the posthemorrhage period. Cardiac output decreased similarly in both groups. Posthemorrhage lactate and glucose concentrations were lower in exercise. The increase in plasma epinephrine was reduced in exercise, with significantly lower levels in epinephrine and norepinephrine noted posthemorrhage. Vasopressin levels and plasma renin activity were not different. In response to hemorrhage after exercise, blood pressure is better maintained although catecholamine levels were reduced, suggesting increased adrenoreceptor sensitivity. In addition, indices of increased glucose utilization and correction of lactate acidosis support a metabolic shift after exercise. Prior exercise alters responses to hemorrhage that mask the extent of hypovolemia and should be considered in the initial evaluation of a patient with hemorrhage caused by traumatic injuries.
Wade
Charles E
CE
US Army Institute of Surgical Research, Fort Sam Houston, Houston, TX 77030, USA. Charles.E.Wade@uth.tmc.edu
D000818:Animals; D002302:Cardiac Output / Q000502:physiology; D002395:Catecholamines / Q000097:blood; D004837:Epinephrine / Q000097:blood; D005260:Female; D006470:Hemorrhage / Q000097:blood* / Q000503:physiopathology*; D051379:Mice; D009638:Norepinephrine / Q000097:blood; D010805:Physical Conditioning, Animal; D011897:Random Allocation; D012083:Renin / Q000097:blood
D002395:Catecholamines; D012083:Renin; D009638:Norepinephrine; D004837:Epinephrine