In this video, Dr. Artour Rakhimov explains vasodilation that is mainly controlled by CO2 levels in the arterial blood. When we have slow and relaxed normal breathing, we have normal CO2 values in the blood (or about 40 mm Hg), see http://www.normalbreathing.com/CO2-vasodilation.php
for more details.
However, people with chronic diseases, such as diabetes, cancer, and heart disease, usually have too low arterial CO2 due to their heavy breathing at rest. This causes vasoconstriction since arteries and arterioles are very sensitive to CO2 changes. As a result, they suffer from low O2 supply to all organs of the human body.
The video is for people with chronic health problems and health professionals.