Abstract
<p>Ischemic preconditioning (IPC) may have profound local and systemic effects that improve blood flow and oxygen delivery to tissues, including skeletal muscle, and has the potential to improve intense aerobic exercise performance, especially that which results in arterial hypoxemia. Purpose: To determine the effects of IPC of the legs on peak exercise capacity (Wpeak), submaximal and peak cardiovascular hemodynamics, and arterial oxygen saturation (SaO2) in trained males at sea level (SL) and simulated high altitude (HA; FIO2 = 13.3%, ~3650 m). Methods: Fifteen highly trained male cyclists and triathletes completed two Wpeak tests (SL and HA) and four experimental exercise trials (10 min at 55% altitude specific Wpeak increasing by 30 W every 2 min until exhaustion) with and without IPC. Results: HA resulted in significant arterial hypoxemia during exercise compared to SL (73 ±1 vs. 93 ± 1% SaO2, p< 0.05) that was associated with 21% lower Wpeak values. IPC resulted in a 1.9 ± 0.8% higher average Wpeak value at SL compared to control (p = 0.032). While IPC resulted in a 4.7 ± 2.3% higher average Wpeak value at HA compared to control, this difference failed to reach statistical significance (p = 0.084). IPC did not significantly affect peak cardiovascular hemodynamics or SaO2 at SL or HA. Conclusions: IPC has little effect on systemic oxygen delivery and future studies must examine its influence on local factors, including blood flow, oxygen delivery, and arteriovenous oxygen difference of the working limb.</p>