Effect of heat stress on vascular outcomes in humans.

In addition to its role as an environmental stressor, scientists have recently demonstrated the potential for heat to be a therapy for improving or mitigating declines in arterial health. Many studies at both ends of the scientific controls spectrum (tightly controlled, experimental vs. practical) have demonstrated the beneficial effects of heating on microvascular function (e.g., reactive hyperemia, cutaneous vascular conductance); endothelial function (e.g., flow-mediated dilation); and arterial stiffness (e.g., pulse-wave velocity, compliance, β-stiffness index). It is important to note that findings of beneficial effects are not unanimous, likely owing to the varied methodology in both heating protocols and assessments of outcome measures. Mechanisms of action for the effects of both acute and chronic heating are also understudied. Heat science is a very promising area of human physiology research, as it has the potential to contribute to approaches addressing the global cardiovascular disease burden, particularly in aging and at risk populations, and those for whom exercise is not feasible or recommended.