George W Rodway1, Anne J Lovelace2, Michael J Lanspa2, Scott E McIntosh3, James Bell4, Ben Briggs2, Lindell K Weaver5, Frank Yanowitz6, Colin K Grissom2. 1. University of Utah School of Nursing, Salt Lake City, UT (Dr Rodway). Electronic address: gwrodway@ucdavis.edu. 2. Department of Pulmonary and Critical Care (Ms Lovelace, Drs Lanspa and Grissom, and Mr Briggs). 3. Division of Emergency Medicine (Dr McIntosh). 4. Intermountain Medical Center (Mr Bell and Dr Weaver), Murray, UT; Hyperbaric Medicine (Mr Bell), LDS Hospital, Salt Lake City, UT. 5. Intermountain Medical Center (Mr Bell and Dr Weaver), Murray, UT; Department of Pulmonary and Critical Care (Dr Weaver); School of Medicine (Drs Weaver and Yanowitz), University of Utah, Salt Lake City, UT. 6. and ECG Services and Cardiac Rehabilitation (Dr Yanowitz); School of Medicine (Drs Weaver and Yanowitz), University of Utah, Salt Lake City, UT.
Abstract
OBJECTIVE:Hypobaric hypoxia decreases exercise capacity and causes hypoxic pulmonary vasoconstriction and pulmonary hypertension. The phosphodiesterase-5 inhibitor sildenafil is a pulmonary vasodilator that may improve exercise capacity at altitude. We aimed to determine whether sildenafil improves exercise capacity, measured as maximal oxygen consumption (peak V̇o2), at moderate altitude in adults 60 years or older. METHODS: The design was a randomized, double-blind, placebo-controlled, crossover study. After baseline cardiopulmonary exercise testing at 1400 m, 12 healthy participants (4 women) aged 60 years or older, who reside permanently at approximately 1400 m and are regularly active in self-propelled mountain recreation above 2000 m, performed maximal cardiopulmonary cycle exercise tests in a hypobaric chamber at a simulated altitude of 2750 m after ingestingsildenafil and after ingesting a placebo. RESULTS: After placebo, mean peak V̇o2 was significantly lower at 2750 m than 1400 m: 37.0 mL · kg(-1) · min(-1) (95% CI, 32.7 to 41.3) vs 39.1 mL · kg(-1) · min(-1) (95% CI, 33.5 to 44.7; P = .020). After placebo, there was no difference in heart rate (HR) or maximal workload at either altitude (z = 0.182; P = .668, respectively). There was no difference between sildenafil and placebo at 2750 m in peak V̇o2 (P = .668), O2 pulse (P = .476), cardiac index (P = .143), stroke volume index (z = 0.108), HR (z = 0.919), or maximal workload (P = .773). Transthoracic echocardiography immediately after peak exercise at 2750 m showed tricuspid annular plane systolic velocity was significantly higher after sildenafil than after placebo (P = .019), but showed no difference in tricuspid annular plane systolic excursion (P = .720). CONCLUSIONS:Sildenafil (50 mg) did not improve exercise capacity in adults 60 years or older at moderate altitude in our study. This might be explained by a "dosing effect" or insufficiently high altitude.
RCT Entities:
OBJECTIVE: Hypobaric hypoxia decreases exercise capacity and causes hypoxic pulmonary vasoconstriction and pulmonary hypertension. The phosphodiesterase-5 inhibitor sildenafil is a pulmonary vasodilator that may improve exercise capacity at altitude. We aimed to determine whether sildenafil improves exercise capacity, measured as maximal oxygen consumption (peak V̇o2), at moderate altitude in adults 60 years or older. METHODS: The design was a randomized, double-blind, placebo-controlled, crossover study. After baseline cardiopulmonary exercise testing at 1400 m, 12 healthy participants (4 women) aged 60 years or older, who reside permanently at approximately 1400 m and are regularly active in self-propelled mountain recreation above 2000 m, performed maximal cardiopulmonary cycle exercise tests in a hypobaric chamber at a simulated altitude of 2750 m after ingesting sildenafil and after ingesting a placebo. RESULTS: After placebo, mean peak V̇o2 was significantly lower at 2750 m than 1400 m: 37.0 mL · kg(-1) · min(-1) (95% CI, 32.7 to 41.3) vs 39.1 mL · kg(-1) · min(-1) (95% CI, 33.5 to 44.7; P = .020). After placebo, there was no difference in heart rate (HR) or maximal workload at either altitude (z = 0.182; P = .668, respectively). There was no difference between sildenafil and placebo at 2750 m in peak V̇o2 (P = .668), O2 pulse (P = .476), cardiac index (P = .143), stroke volume index (z = 0.108), HR (z = 0.919), or maximal workload (P = .773). Transthoracic echocardiography immediately after peak exercise at 2750 m showed tricuspid annular plane systolic velocity was significantly higher after sildenafil than after placebo (P = .019), but showed no difference in tricuspid annular plane systolic excursion (P = .720). CONCLUSIONS:Sildenafil (50 mg) did not improve exercise capacity in adults 60 years or older at moderate altitude in our study. This might be explained by a "dosing effect" or insufficiently high altitude.
Authors: Timothy J Roberts; Andrew T Burns; Richard J MacIsaac; Andrew I MacIsaac; David L Prior; André La Gerche Journal: J Appl Physiol (1985) Date: 2019-05-02
Authors: Hung-Yuan Cheng; Matthew C Frise; M Kate Curtis; Nicole K Bart; Nayia Petousi; Nick P Talbot; George M Balanos; Peter A Robbins; Keith L Dorrington Journal: Physiol Rep Date: 2019-08