EFFECTS OF ACUTE LOCAL HEATING ON SKELETAL MUSCLE INTERSTITIAL OXYGENATION

The oxygen transport pathway comprises a series of physiological transfer steps that promote the movement of oxygen from the atmosphere to cell mitochondria. Dynamic adjustments within this pathway are essential for meeting the metabolic demands of skeletal muscle contractions. During exercise or daily movement, oxygen delivery must be closely matched to muscle oxygen demand to sustain contractile function. A key mechanism driving increases in oxygen delivery to skeletal muscle is vasodilation, which is accomplished mainly by the relaxation of smooth muscle within the arteriolar network.

Evidence indicates that acute local hyperthermia can elevate skeletal muscle oxygen delivery via peripheral hemodynamic mechanisms. These adjustments can take place without alterations in core temperature or central hemodynamics. However, whether acute local heating increases skeletal muscle interstitial oxygen pressures (PO₂is) remains to be determined. As dictated by Fick’s law, PO₂is constitutes the exclusive driving force for oxygen flux into the myocyte, thus supporting oxidative phosphorylation.

The primary aim of my thesis study was to determine if peripheral mechanisms control skeletal muscle oxygenation with acute localized heating in healthy animals. In Chapter 2, we report no change in skeletal muscle oxygenation with acute localized heating in healthy animals. Chapter 3 summarizes the current results, limitations of the study presented in Chapter 2, and future research directions based on our findings.