Circulation

• Cardiac output describes the volume of blood pumped out of the heart per minute
• Cardiac output is roughly 5 litres per minute in a typical human adult at rest (it increases to ~25 L/min during heavy exercise)
• Blood is distributed to body organs according to physiological requirements and this distribution changes with exercise
• Blood flow to the brain is largely unchanged during exercise
• Blood flow to the heart wall, muscles and skin is increased during excercise
• Blood flow to the kidneys, liver and digestive system is decreased during exercise
• Blood vessels will vasodilate during exercise to improve circulation and facilitate heat loss via the skin
• What is vasodilation?

  the widening of blood vessels