Key result
Single-leg hypoxic cycling yields ~5% higher tissue saturation and greater femoral blood flow vs double-leg.
Why the study?
Large muscle mass exercise intensity declines at altitude from reduced oxygen delivery, prompting investigation into whether single-leg cycling prevents tissue oxygenation reduction in hypoxia.
Does single-leg cycling improve tissue oxygenation compared to double-leg cycling in hypoxic conditions in healthy individuals?
Does single-leg cycling improve tissue oxygenation compared to double-leg cycling in hypoxic conditions in healthy individuals?
Absolute Event Rate: 63.3% vs 60.2%
p-value: p=<0.001
Single-leg cycling in hypoxic conditions improves femoral blood flow and tissue oxygenation compared to double-leg cycling, suggesting reduced muscle mass exercise can offset hypoxia-induced oxygenation declines.
May support testing reduced-muscle-mass exercise in hypoxia; leaves open extension to patients or practice change.
The intensity of large muscle mass exercise declines at altitude due to reduced oxygen delivery to active muscles. The purpose of this investigation was to determine if the greater limb blood flow during single-leg cycling prevents the reduction in tissue oxygenation observed during traditional double-leg cycling in hypoxic conditions. Ten healthy individuals performed bouts of double and single-leg cycling (4, four-minute stages at 50−80% of their peak oxygen consumption) in hypoxic (15% inspired O2) and normoxic conditions. Heart rate, mean arterial pressure, femoral blood flow, lactate, oxygenated hemoglobin, total hemoglobin, and tissue saturation index in the vastus lateralis were recorded during cycling tests. Femoral blood flow (2846 ± 912 mL/min) and oxygenated hemoglobin (−2.98 ± 3.56 au) during single-leg cycling in hypoxia were greater than double-leg cycling in hypoxia (2429 ± 835 mL/min and −6.78 ± 3.22 au respectively, p ≤ 0.01). In addition, tissue saturation index was also reduced in the double-leg hypoxic condition (60.2 ± 3.1%) compared to double-leg normoxic (66.0 ± 2.4%, p = 0.008) and single-leg hypoxic (63.3 ± 3.2, p < 0.001) conditions. These data indicate that while at altitude, use of reduced muscle mass exercise can help offset the reduction in tissue oxygenation observed during larger muscle mass activities allowing athletes to exercise at greater limb/muscle specific intensities.
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Draper et al. (2022) studied Healthy individuals in hypoxic environments (n=10). Single-leg cycling vs. Double-leg cycling was evaluated on Tissue saturation index (p=<0.001). Single-leg cycling in hypoxia resulted in a higher tissue saturation index (63.3% vs 60.2%, p<0.001) and greater femoral blood flow compared to double-leg cycling.
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