Year of Award

2014

Document Type

Thesis

Degree Type

Master of Science (MS)

Degree Name

Health and Human Performance (Exercise Science Option)

Department or School/College

Department of Health and Human Performance

Committee Chair

Brent Ruby

Commitee Members

Charles Dumke, Holly Thompson

Keywords

stimulant, endothelin, vascular pressure, hypoxia, pharmaceutical

Abstract

Recent research efforts have attempted to determine the effectiveness of the combination of a pharmacological cardiac stimulant (theophylline) and pulmonary vasodilator (ambrisentan) in attenuating performance losses and mountain sickness at altitude. This combination has been observed to improve hypoxic exercise performance in rats, but never tested in human subjects. In the current study, 30 male participants were tested in a paired fashion to assess whether this drug combination would improve exercise performance and/or decrease symptoms of AMS. The experimental group (EXP, n = 15) received a treatment of 400 mg theophylline and 5 mg ambrisentan, while the placebo group (PLA, n = 15) received a placebo combination. Data collection was performed in the field at an altitude of 4,267 m. Participants completed two 2-mile time trials (TT) on subsequent days, between which they spent the night at 3,048 m. Treatment with theophylline and ambrisentan was not associated with improved 2-mile TT performances or AMS symptoms. The EXP group had significantly lower measures of diastolic blood pressure and mean arterial pressure compared to PLA while at altitude (69.2 ± 7.9 vs 77.7 ± 8.0 mmHg and 90.8 ± 8.9 vs 97.2 ± 7.9 mmHg, respectively), main effect for group, p<0.05. Significantly, this study was the first to assess this drug combination in human subjects at altitude in a field setting. Additionally, the observed reduction in vascular pressures as a result of treatment may have positive implications for the health state of sojourners to altitude.

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© Copyright 2014 Hilary Linda Palakovich