Beloka, S., Janssen, C., Deboeck, G., Adamopoulos, D., Randria, J., Naeije, R., & de Borne, P. V. (2009). Effect of salbutamol on chemoreflex and metaboreflex contribution to endurance performance and muscle strength in nonasthmatic men. ACSM 56th Annual Meeting, Seattle, Washington. Presentation number 668.

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"Ventilatory stimulation and its chemical control are important when beta 2 adrenergic agonists are used in asthma treatment. In elite athletes and general population, asthma is a very common condition. Use of beta 2 adrenergic agonists by competitive athletes is strictly prohibited by WADA in sport disciplines due to their assumed ergogenic action, such as an increase of peripheral chemosensitivity and metabolism, in endurance performance, and muscle strength."

This study investigated the effect of salbutamol on chemoreflex and the metaboreflex, and its ergogenic contribution in nonasthmatic men. Healthy males (N = 11) were measured during 30 minutes of intravenously administered salbutamol (10 mg/minute) and a placebo following a double-blind, placebo-controlled, randomized cross-over experimental design. Measures were taken of salbutamol on MSNA, ventilatory responses to hyperoxic hypercapnia (7% CO2 in O2 ), DVE/DPetCO2 , and isocapnic hypoxia (10% O2 in N2), DVE/DSpO2 , and to an isometric muscle contraction followed by a local circulatory arrest (metaboreflex) at rest, followed by an incremental cardiopulmonary exercise test and a maximal isokinetic muscle strength test (Cybex).

At rest, heart rate, systolic blood pressure, ventilation, and MSNA burst incidence, and MSNA burst frequency, Pet CO2 , SaO2 remained unchanged after the drug administration. During hypoxia, heart rate and ventilation increased, however, MSNA, blood pressure, SaO2 , continued unchanged during salbutamol compared to placebo. There were no changes in heart rate, MSNA, ventilation, SpO2 , or PetCO2 during hypercapnia or metaboreflex stimulation with salbutamol. In the incremental cardiopulmonary exercise test, only the Ve/VO2 slope at maximal exercise and O2 pulse at the anaerobic threshold were significantly changed by salbutamol, while there were no effects on heart rate, VO2max, or other ventilatory equivalents. Salbutamol had no effects on a maximal isokinetic muscle strength test.

Implication. Intravenously administered salbutamol increases ventilation but does not influence aerobic exercise capacity or muscle strength. [This is yet another study that does not support the assumptions of WADA about banned substances.]

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