Vasodilation occurs when the smooth muscles in our blood vessels relax and thus the interior of the blood vessels, called the lumen, becomes wider in diameter. And now with the increase in space within each vessel, there is less vascular resistance so there is much greater rate of blood flow.
Also with the cardiac output remaining constant but a greater volume of space available, your blood pressure decreases.
- ↑ https://www.medicinenet.com/script/main/art.asp?articlekey=5965
- ↑ Rakhimov, D. A. (2004-2013). NormalBreathing.com. Retrieved from http://www.normalbreathing.com/