Department of Cardiology, S. Luca Hospital, IRCCS, Istituto Auxologico Italiano, Milan, Italy.
Cardiovasc Ther. 2012 Aug;30(4):240-8. doi: 10.1111/j.1755-5922.2011.00261.x. Epub 2011 Mar 11.
Exposure to high altitude (HA) hypoxia decreases exercise performance in healthy subjects. Although β-blockers are known to affect exercise capacity in normoxia, no data are available comparing selective and nonselective β-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.
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).
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).
Exercise performance is better preserved with nebivolol than with carvedilol under acute exposure to HA hypoxia in healthy subjects.
高海拔（HA）低氧暴露会降低健康受试者的运动表现。虽然β受体阻滞剂已知会影响正常氧合下的运动能力，但在健康受试者急性暴露于 HA 低氧时，尚无比较选择性和非选择性β肾上腺素能阻滞对运动能力影响的数据。我们比较了 nebivolol 和 carvedilol 对急性暴露于 HA 低压缺氧的健康受试者运动能力的影响。
在这项双盲、安慰剂对照试验中，27 名来自海平面（SL）的未经训练的健康居民（15 名男性，年龄 38.3 ± 12.8 岁）被随机分为安慰剂组（n = 9）、 carvedilol 25 mg 每日两次（n = 9）或 nebivolol 5 mg 每日一次（n = 9）。主要终点是通过心肺运动测试在海平面上进行的运动表现评估，在没有治疗的情况下进行，并且在至少 3 周的治疗后，在 SL 和到达 HA（4559 m）后不久进行。
HA 低氧显著降低静息和峰值血氧饱和度、峰值工作量、VO2 和心率（HR）（P < 0.01）。与 SL（无治疗）相比，治疗之间的变化有所不同：（1）与 carvedilol 相比（-37.6%），nebivolol 更好地保留了峰值 VO2（-22.5%）（P < 0.01）；（2）与 nebivolol 相比（-24.8 ± 13.6 次/分）， carvedilol 使峰值 HR 降低（-43.9 ± 11.9 次/分）更多（P < 0.05）；（3）与 carvedilol 相比，峰值分钟通气量（VE）降低（-9.3%），与 nebivolol 相比，峰值 VE 增加（+15.2%）（P = 0.053）。仅峰值 VE 变化在多元分析中独立预测峰值 VO2 的变化（R= 0.62，P < 0.01）。
在健康受试者急性暴露于 HA 低氧时，nebivolol 比 carvedilol 更好地保留运动表现。
