Hackney, A. C., Viru, A., Viru, M., Karelson, K., Janson, T., Siim, K., & Fischer, K. (2006). Adrenergic influence on the hormonal response to exercise in endurance trained men. Medicine and Science in Sports and Exercise, 38(5), Supplement abstract 2572.

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This study evaluated the influence of adrenergic factors on the hormonal responses to maximal exercise in endurance trained men. This was achieved by testing young healthy men during exercise in conditions of Beta-adrenergic blockade and in simulated competition situations that stimulated sympatho-adrenal activity. Ss (N = 7) performed maximal exercise to exhaustion on a treadmill during four conditions administered in random order: (1) control-placebo, (2) after administration of 80 mg propranolol, (3) in a simulated competition after a placebo intake, and (4) in a simulated competition after propranolol intake. Blood samples were obtained before (pre-) and three minutes post-exercise and assayed for select hormones (cortisol, growth hormone, testosterone).

All Beta-adrenergic blockade and competition situations caused significant augmented post-exercise cortisol responses (25-45%) when compared to the control-placebo condition. The simulated competition condition resulted in significantly greater post-exercise cortisol responses than the control-placebo or the Beta-blockage conditions. Growth hormone and testosterone post-exercise responses were slightly, but significantly, higher in the Beta-adrenergic blockade conditions than either placebo conditions.

Implication. Central adrenergic influences appear to restrict the cortisol, growth hormone, and testosterone responses to maximal exercise. The heightened stress of competition resulted in a further enhancement of cortisol levels

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