What “head-rush” says about your health
Many people get a lightheaded sensation sometimes when standing up from sitting position
When you are seated, your blood naturally gathers in the veins of your lower limbs
Then on standing up, this effect is emphasised by gravity, so the blood is pulled back towards the floor so that your heart does not get enough blood returned to it
This means that the heart can’t pump blood to the lungs and oxygenate the blood
Importantly, this means that the brain isn’t getting enough oxygenated blood, and the brain is the bodies number 1 priority so for a moment, the heart goes into “overdrive” to try and fix this problem
At the same time though, the limbs are not prioritised, especially because the body would technically benefit from being on the floor (removes gravity pulling the blood downwards), hence why you may collapse
Why this causes your head to feel ‘light’ and then the sensation of blood running up to it (head-rush) is because that is exactly what is happening! The brain is low on blood so your heart pumps harder to get the blood up there!
So the answer is, in most people, it’s a perfectly healthy phenomenon. It could be an indicator that your blood pressure is low, which may be worth seeing your GP about. However unlike high blood pressure, low blood pressure doesn’t tend to cause many problems in your body in the long run.
Sam Fitzpatrick Final Year Medical Student, Cardiff University.
Milad Rouf Final Year Medical Student, Cardiff University.
G. Pocock et al. 2014, Human Physiology 4th Edition. Chapter 1, “The Role of the Central Nervous System in Control of the Circulation”