Ever wondered why you get dizzy when you stand up?

You might have encountered it or at least heard someone go "WOW" right after they got off the chair or their bed and almost fell right back into the chair. It was plausibly because they got up too fast after a long time of sitting and got dizzy. It's a fairly common phenomenon that many people face day in and day out. Some of them feel dizzy, a few of them have fuzzy or blurry sight for a second and then recover and some might have a flash of confusion. But have you Ever Wondered why this happens?

This effect is termed Orthostatic hypotension. The word hypotension might give you a clue that this phenomenon is related to blood pressure. When you sit for a prolonged period, the blood pressure tends to slightly reduce because the ends of your body are relatively closer to the heart (which is why it is recommended to check blood pressure while sitting down). So when we get up after a while the pressure is still less but the body is fully stretched so this means that the brain is not getting enough oxygenated blood. In a matter of seconds, the heart rate increases to overcome the reduced blood pressure which is how we recover to our original balance.

Now in the case of getting up after lying down for a prolonged period, the scenario is slightly different. when we lie down, the blood is uniformly spread along the horizontal axis and it is under circulation. Take a half-filled bottle of water for example. When the bottle is lying horizontally, the water is evenly spread along the length of the bottle. When we change the axis and place the bottle upright all the water moves down. Similarly, when we stand up gravity being gravity pulls all the blood down our body thus causing a lack of sufficient blood flow to the brain again. So we get the same dizziness or blurry eyesight for a short span of time until the brain is back to its blood-rejuvenated state. 

A few ways this can be prevented is by staying well hydrated and when getting out of bed, sit on the edge of the bed for a minute before standing, and follow the same while getting out of a chair too.

So next time take it slow and you will be good to go;)