There are several reasons that you will see stars when you are stretching. First of all, maybe it is because that you stand up very quickly, then the inertia in your body causes the blood to run out of your head and neck and upper body, thus making you see stars and in some cases some people may even faint. And the veins and arteries are strecthed a bit as well, and in doing that you increase the distance that blood has to travel around the body which means that again your brain gets less blood and you see stars. Besides, when you are stretching you rentire body, you are squeezing many muscles of your body at the same time, therefore, they all require oxygen, and this sudden requirement of oxygen by all the muscles being stretched will cause less oxygen to be available in the blood for the brain and hence you see stars. So, to avoid seeing stars or even faint, you can pay attention not to stand up too quickly. And notice that some foods which are good for blood can be added to your diet to help you keep in a normal blood pressure and keep fit.
