Matching the heart to heat-induced circulatory load: heat-acclimatory responses.
Heat acclimation enhances cardiac efficiency by increasing stroke volume and decreasing heart rate. These adaptations involve biochemical changes in the contractile apparatus, switched on by altered expression of genes coding contractile and calcium-regulatory proteins and partially mediated by persistent low thyroxine. Heat acclimation also produces cross-tolerance to oxygen deprivation, thus reinforcing cardiac adaptation to oxygen demand/supply mismatching via energy-sparing pathways.
Horowitz
Michal
M
Division of Physiology, Hadassah School of Dental Medicine, The Hebrew University, Jerusalem 91120, Israel.
D000064:Acclimatization; D000818:Animals; D001775:Blood Circulation / Q000502:physiology*; D006321:Heart / Q000502:physiology*; D006358:Hot Temperature; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism