Cardiovascular drift Increase in HR as exercise at same intensity Why Stroke Volume decreases when working in warmer climates Because there is an increase in blood flow to the skin in an attempt to lose heat through conduction, convection and evaporation This means less blood returning to the heart Therefore reduced SV To maintain cardiac output, HR must increase

CV Drift 2. Blood plasma volume decreases Fluid seeps into surrounding tissues and cells Fluid lost to sweating If athletes fail to re-hydrate, can further reduce the volume of blood returning to heart Causing a fall in SV