During strenuous exercise, which organs experience increased blood flow?

• A. Skeletal muscles, heart, skin
• B. Brain, Liver, Kidneys
• C. Lungs, Brain, Heart
• D. Skeletal muscles, Brain, Kidneys

Answer: (A)

During strenuous exercise, blood is redirected to tissues that need it most to fuel activity and regulate body temperature. Skeletal muscles are the primary sites of work, so their demand for oxygen and nutrients skyrockets, and the arterioles feeding active muscles dilate to increase flow. The heart itself also needs more blood to sustain the higher cardiac output and supply the myocardium with oxygen. At the same time, skin blood vessels dilate to release heat produced by the working muscles, helping prevent overheating.

Meanwhile, blood flow to organs not immediately vital for exercise, like the kidneys and liver, is reduced to conserve blood for muscles and skin. The brain generally maintains steady perfusion through autoregulation, and the lungs’ perfusion rises with overall cardiac output but isn't the primary redistribution highlighted during intense activity.