Effects of Compression Sleeves on Muscle Oxygen Saturation During Graded Exercise in Acute Hypoxia

Lower partial pressure at altitude reduces the amount of oxygen able to be delivered to exercising muscles. Interventions to restore muscle oxygen saturation during hypoxic exercise have the potential to improve related measures like cardiac output and VO2. PURPOSE: The purpose of our study was to explore the effects of lower leg compression sleeves on muscle oxygen saturation during graded exercise in acute, normobaric hypoxia. METHODS: Seven male participants were recruited (Age = 24.5±3.2; Bodyfat% = 21.8±2.7; VO2 = 42.2±7.1) and underwent two graded exercise bouts at 20%, 40% and 60% of sea level VO2max in normobaric hypoxia (13.5% FiO2). During one session, participants were instructed to wear compression sleeves from their lower ankle to upper calf. Each session consisted of a 20 minute rest in hypoxia before cycling began. Each stage was 4 minutes long, with a 10 minute recovery period after completion. Muscle oxygen saturation was measured in the quadriceps and gastrocnemius. A physioflow impedance cartography device and a metabolic cart were used for measuring cardiovascular and metabolic variables. All measurements were recorded through rest, exercise, and recovery stages of the session. RESULTS: A two-way repeated measures ANOVA analysis showed that compression sleeves had a significant interaction effect with exercise stage on muscle oxygen saturation, decreasing for the quadricep (p<0.001) and the approaching significance in the gastrocnemius (p=0.07), as well as decreasing stroke volume (p=0.001). No significant effect was observed for VO2/kg (p=0.8). CONCLUSION: These results indicate that compression sleeves can improve muscle oxygen saturation through an increased stroke volume. This has the potential to improve exercise performance during exercise in hypoxia, although results do not extend into metabolic measures.