Acclimatization (to heat)

In a hot environment, the following reversible changes occur - acclimatization - to adapt the body:

• cardiovascular system:
  • early: increase in heart rate and decrease in stroke volume; overall product is increased cardiac output
  • late: overall further increase in cardiac output due to increased stroke volume, increased plasma proteins, and increase in blood volume but decreased heart rate
• thermoregulation: increased physiological sweating
• fluid balance: increased aldosterone secretion, enhancing sodium conservation in kidneys and sweat ducts