Standing Up Too Fast

Uh oh. You just stood up too fast.

At first, you don’t really notice anything in particular, but after a second or two, everything seems kind of distant. Your fingers and toes are tingling, and is that tingling spreading up your body?

If so, you had better sit down right away! Either way, it’s a good idea to sit down any time you stand up too fast.

What’s going on here?

Whenever you stand quickly, the blood that’s in your legs and abdomen remains somewhat in place due to gravity. This means less blood ends up going to your heart when it beats, which causes your heart to pump out less blood.

Since less blood pumps out, that’s a bit less blood going into your brain. It turns out that you need blood to remain on your feet.

As soon as you sit back down (or fall), your heart and head are closer to the same level.

The issue is that not enough oxygenated blood is getting to your brain, something I’ve had the opportunity to study first hand over the last 30 years.

The sensation you get when you’re choked in jiu jitsu is really similar to this feeling. There isn’t enough oxygen coming in, so you’re going to sleep soon—though the mechanism with a choke is very different; the idea is to cut off the blood vessels in the neck so oxygenated blood stops flowing in, whereas when you stand up too fast, the blood flow is reduced by gravity.

That all makes sense, but what about those tingling fingers and toes? What about that general sense of numbness and the little prickles of light you see entering from all sides?

The sparkles you see are caused by that same brief drop in blood flow to your brain, but the why is where things get really interesting for me. It turns out that neurons rely on a constant flow of energy in order to function properly. This energy comes from oxygen and glucose, both delivered by your blood.

What you’re seeing here is your visual circuitry’s inability to keep a signal flowing. Instead, it’s a lot more like the TV is on a static station—and, in fact, those sparkles look a lot like TV static, don’t they?

The tingles are a little different. When the blood pressure in your brain drops, you tend to start breathing a little differently—sometimes without noticing.

This means you exhale more carbon dioxide, which makes your blood have less CO₂ in it. The delicate balance in your blood is now off-kilter, and your nerves become a lot more sensitive. Some of them tingle as a result of your blood’s alkaline state.