Abstract
BACKGROUND:
This study aimed to assess the efficacy of acute sub-anesthetic dosages of xenon inhalation to cause erythropoiesis, and determine the effect of chronic xenon dosing on hematological parameters and athletic performance.
METHODS:
To assess the acute effects, 7 subjects breathed three sub-anesthetic concentrations of xenon: FiXe 30% for 20 minutes, FiXe 50% for 5 minutes and FiXe 70% for 2 minutes. EPO was measured at baseline, during and post xenon inhalation. To determine the chronic effects, 8 subjects breathed FiXe 70% for 2 minutes on 7 consecutive days, and EPO, total blood and plasma volume were measured. Phase II involved assessment of 12 subjects for EPO, total blood volume, V̇O2max, and 3km time before and after random assignment to 4 weeks of xenon or sham gas inhalation.
RESULTS:
FiXe 50% and 70% stimulated an increase in EPO at 6 hours (+2.3mIU/mL [95%CI 0.1-4.5], P=0.038) and at 192 hours post inhalation (+2.9mIU/mL [95%CI 0.6-5.1], P=0.017), respectively. Seven consecutive days of dosing significantly markedly elevated plasma volume (+491mL [95%CI 194-789], P=0.002). Phase II showed no significant effect on EPO, hemoglobin mass, plasma volume, V̇O2max, or 3 km time.
CONCLUSIONS:
Acute exposure to sub-anesthetic doses of xenon caused a consistent increase in EPO, and 7 consecutive days of xenon inhalation significantly expanded plasma volume. However, this physiological response appeared to be transient and 4 weeks of xenon inhalation did not stimulate increases in plasma volume or erythropoiesis, leaving cardiorespiratory fitness and athletic performance unchanged.