Effects of β2-adrenergic stimulation on exercise capacity in normal subjects

• Published in: European journal of applied physiology 2011-09, Vol.111 (9), p.2239-2247
• Main Authors: Beloka, S. P., Janssen, C., Woff, E., Brassine, E., Deboeck, G., Randria, J., Philippart de Foy, V., van de Borne, P., Naeije, R.
• Format: Article
• Language: English
• Subjects: Adrenergic beta-2 Receptor Agonists - pharmacology; Adult; Albuterol - pharmacology; Athletic Performance - physiology; Biological and medical sciences; Biomedical and Life Sciences; Biomedicine; Cross-Over Studies; Double-Blind Method; Exercise - physiology; Exercise Test; Exercise Tolerance - drug effects; Exercise Tolerance - physiology; Fundamental and applied biological sciences. Psychology; Health; Human Physiology; Humans; Male; Muscle, Skeletal - drug effects; Muscle, Skeletal - innervation; Occupational Medicine/Industrial Medicine; Original Article; Placebos; Pulmonary Ventilation - drug effects; Pulmonary Ventilation - physiology; Receptors, Adrenergic, beta-2 - metabolism; Sports Medicine; Sympathetic Nervous System - drug effects; Sympathetic Nervous System - physiology; Vertebrates: body movement. Posture. Locomotion. Flight. Swimming. Physical exercise. Rest. Sports; Young Adult
• ISSN: 1439-6319; 1439-6327
• DOI: 10.1007/s00421-011-1856-9

β2-Adrenergic receptor agonists are believed to present with ergogenic properties. However, how combined respiratory, cardiovascular and muscular effects of these drugs might affect exercise capacity remain incompletely understood. The effects of salbutamol were investigated in 23 healthy subjects. The study was randomised, placebo-controlled in double-blind and followed a cross-over design. Salbutamol was given at the dose of 10 μg/min in 11 subjects and 20 μg/min iv in the other 12 subjects. Measurements included muscle sympathetic nerve activity (MSNA), ventilatory responses to hyperoxic hypercapnia (7% CO 2 in O 2, central chemoreflex), isocapnic hypoxia (10% O 2 in N 2 , peripheral chemoreflex) and isometric muscle contraction followed by a local circulatory arrest (metaboreflex), cardiopulmonary exercise test (CPET) variables and isokinetic muscle strength. Salbutamol 10 μg/min increased heart rate and blood pressure, while MSNA burst frequency remained unchanged. Peripheral chemosensitivity increased, as evidenced by an increased ventilatory response to hypoxia, but ventilatory responses to hypercapnia or muscle ischaemia remained unchanged. The effects of salbutamol 20 μg/min were similar. Both doses of salbutamol did not affect CPET. Only the higher dose of salbutamol decreased the anaerobic threshold, but this was not associated with a change in V O 2 max. Salbutamol increased the slopes of ventilation as a function of V O 2 ( P