Effects of Beta-Blockade on Exercise Performance at High Altitude: A Randomized, Placebo-Controlled Trial Comparing the Efficacy of Nebivolol versus Carvedilol in Healthy Subjects.

Author(s): Valentini M, Revera M, Bilo G, Caldara G, Savia G, Styczkiewicz K, Parati S, Gregorini F, Faini A, Branzi G, Malfatto G, Magri D, Agostoni P, Parati G

Affiliation(s): Department of Cardiology, S. Luca Hospital, IRCCS, Istituto Auxologico Italiano; Milan, Italy Division of General Medicine, S. Giuseppe Hospital, IRCCS, Istituto Auxologico Italiano, Verbania, Italy I Department of Cardiology and Hypertension, Jagiellonian University, Krakow, Poland Dipartimento di Scienze Cliniche e Molecolari, Sapienza, Universita di Roma, Italy Centro Cardiologico Monzino, IRCCS, Milan, Italy Department of Cardiovascular Sciences, University of Milano, Milan, Italy Department of Clinical Medicine and Prevention, University of Milano-Bicocca, Milan, Italy.

Publication date & source: 2011-03-11, Cardiovasc Ther., [Epub ahead of print]

Aims: Exposure to high altitude (HA) hypoxia decreases exercise performance in healthy subjects. Although beta-blockers are known to affect exercise capacity in normoxia, no data are available comparing selective and nonselective beta-adrenergic blockade on exercise performance in healthy subjects acutely exposed to HA hypoxia. We compared the impact of nebivolol and carvedilol on exercise capacity in healthy subjects acutely exposed to HA hypobaric hypoxia. Methods: In this double-blind, placebo-controlled trial, 27 healthy untrained sea-level (SL) residents (15 males, age 38.3 +/- 12.8 years) were randomized to placebo (n = 9), carvedilol 25 mg b.i.d. (n = 9), or nebivolol 5 mg o.d. (n = 9). Primary endpoints were measures of exercise performance evaluated by cardiopulmonary exercise testing at sea level without treatment, and after at least 3 weeks of treatment, both at SL and shortly after arrival at HA (4559 m). Results: HA hypoxia significantly decreased resting and peak oxygen saturation, peak workload, VO(2) , and heart rate (HR) (P < 0.01). Changes from SL (no treatment) differed among treatments: (1) peak VO(2) was better preserved with nebivolol (-22.5%) than with carvedilol (-37.6%) (P < 0.01); (2) peak HR decreased with carvedilol (-43.9 +/- 11.9 beats/min) more than with nebivolol (-24.8 +/- 13.6 beats/min) (P < 0.05); (3) peak minute ventilation (VE) decreased with carvedilol (-9.3%) and increased with nebivolol (+15.2%) (P= 0.053). Only peak VE changes independently predicted changes in peak VO(2) at multivariate analysis (R= 0.62, P < 0.01). Conclusions: Exercise performance is better preserved with nebivolol than with carvedilol under acute exposure to HA hypoxia in healthy subjects. (c) 2011 Blackwell Publishing Ltd.