Ischemic preconditioning: Potential impact on exercise performance and underlying mechanisms

Originally, in clinical settings, ischemic preconditioning (IPC) has been used to delay cardiac cell injury and protect against myocardial and vascular damage. Furthermore, as this manipulation is relatively easy and noninvasive, previous studies have examined how IPC may have beneficial effects on exercise performance. However, because of various factors, such as different populations, exercise modes and intensities, and IPC protocols, not enough evidence is available to achieve a consensus on the impact of IPC on exercise performance, e.g., time to failure during exercise, time trial performance, and peak power. Existing evidence suggests that IPC seems not to impair exercise performance, though one study found an impairment. However, about half of the previous studies showed beneficial effects of IPC on exercise performance. Similarly, the physiological responses from IPC are varied. It is still possible that various factors, such as exercise mode and intensity, heterogeneous population and IPC protocol may affect exercise performance. Previous studies showed that effective blood flow via an increase in nitric oxide and the improvement of metabolic efficiency might be candidate factors that can explain the effect of IPC on exercise performance, although no direct evidence has been obtained. This review aims to identify potential sources of variation in these effects on exercise performance with IPC.