Incremental shuttle walking test for calf muscle oxygenation assessment in peripheral arterial disease: a cross-sectional study.

People with peripheral arterial disease (PAD) and intermittent claudication (IC) experience impaired walking due to an imbalance between muscle oxygen supply and demand during exercise. Studies with near-infrared spectroscopy (NIRS) during treadmill tests reveal notable tissue deoxygenation with slow recovery. This cross-sectional study aimed to compare behavior of calf muscle oxygenation during the incremental shuttle walking test (ISWT) with a continuous treadmill test (3.2 km/h, 10% incline) and to correlate NIRS results between tests in PAD patients. Sixty individuals with IC, 37 men (61.7%), mean age 66.25 ± 10.35 years participated in the study. Both tests were performed on the same day with a 30-minute rest, in randomized order. NIRS-derived calf muscle tissue oxygenation variables were measured at rest and during exercise. Typical PAD tissue oxygenation patterns were observed in both tests, with significant differences (p < 0.05) in oxygenation values during exercise for the variables delta of tissue oxygen saturation (ΔStO) and reoxygenation rates. All tissue oxygenation variables analyzed, except reoxygenation rate, showed a significant and directly proportional correlation between the two tests. These results suggest that NIRS during ISWT could be a viable method for assessing tissue oxygenation in PAD.