How do blood vessels change during exercise?

During exercise, blood vessels dilate to increase blood flow and oxygen supply to the muscles.

When you start exercising, your muscles need more oxygen to produce the energy required for the physical activity. This increased demand for oxygen is met by an increase in your heart rate and the volume of blood that is pumped with each beat. However, this alone is not enough. The blood vessels, particularly the arteries and arterioles, in your muscles also need to expand, a process known as vasodilation.

Vasodilation is facilitated by the release of certain chemicals such as nitric oxide, which relaxes the smooth muscle in the walls of the blood vessels. This allows the vessels to expand and accommodate a greater volume of blood. The increased blood flow not only delivers more oxygen, but also more nutrients to the muscles, and helps to remove waste products such as carbon dioxide and lactic acid.

In addition to vasodilation, the body also redistributes blood during exercise. Under resting conditions, a large proportion of your blood supply is directed to your abdominal organs. However, during exercise, the blood flow to these areas is reduced, and more blood is directed towards your skeletal muscles, lungs and heart. This redistribution of blood is controlled by the autonomic nervous system, which constricts the blood vessels in less active areas and dilates those in the active muscle tissues.

In summary, the changes in blood vessels during exercise involve vasodilation to increase blood flow and oxygen supply to the muscles, and the redistribution of blood from less active to more active areas. These changes are crucial for meeting the increased metabolic demands of the muscles during physical activity.