This describes blood vessels getting smaller in order to slow down and restrict the movement of blood. After eating, for instance, the need for oxygen is not high, meaning that vessels can get smaller since there is no immediate need for large levels of oxygen.
The short and long term changes in the cardiovascular system
• Doing exercise over a long period of time makes the size and thickness of the heart increase, making it stronger. In the same way the heart can weaken as a result of no exercise over a long period of time.
• Long term exercise causes blood vessels to become more elastic, meaning they can expand more and increase the speed in which blood is transported.