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Uploaded:2018-12-31
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Spines are naturally curved, not straight, so what good posture actually looks like isn't as straightforward as you might think.

Hosted by: Olivia Gordon

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Sources:

Global Burden of Disease
https://ard.bmj.com/content/73/6/968
https://www.nhs.uk/news/lifestyle-and-exercise/back-pain-leading-cause-of-disability-study-finds/

Dextrocardia and spinal rotation
https://www.ncbi.nlm.nih.gov/pubmed/19506918
https://www.ncbi.nlm.nih.gov/pubmed/16741456

Sitting advice
https://www.npr.org/sections/health-shots/2018/09/24/649169060/cant-get-comfortable-in-your-chair-heres-what-you-can-do
https://www.npr.org/sections/goatsandsoda/2018/08/13/636025077/to-fix-that-pain-in-your-back-you-might-have-to-change-the-way-you-sit

Sedentary behavior
https://health.gov/news/blog-bayw/2013/01/decreasing-sedentary-behavior-and-physical-inactivity-by-moving-more-and-sitting-less/
https://www.sciencedirect.com/science/article/pii/S0004951414602877
https://www.ncbi.nlm.nih.gov/pubmed/22951407

No one definition of posture
https://www.sciencedirect.com/science/article/pii/S1356689X12000938
https://www.tandfonline.com/doi/abs/10.1080/09593980151143228

Wheelchair lung capacity
https://www.sciencedirect.com/science/article/pii/S0003999305014723

Images:

http://www.thinkstockphotos.com/image/stock-photo-medical-illustration/483780512
http://www.thinkstockphotos.com/image/stock-photo-human-anatomy-drawing-old-canvas/667381086
http://www.thinkstockphotos.com/image/stock-photo-3d-illustration-of-spine-medical-concept/860775922
http://www.thinkstockphotos.com/image/stock-photo-human-spine-in-details-vertebra-bone-marrow/615079558
http://www.thinkstockphotos.com/image/stock-photo-the-human-body-spine/868466000
http://www.thinkstockphotos.com/image/stock-illustration-sciatic-nerve-pain-locatio/824757452
https://commons.wikimedia.org/wiki/File:Situs_inversus_chest_Nevit.jpg
http://www.thinkstockphotos.com/image/stock-illustration-girl-sitting-posture-set/648683388
http://www.thinkstockphotos.com/image/stock-illustration-correct-and-uncorrect-bad-sitting/636288838
http://www.thinkstockphotos.com/image/stock-photo-woman-on-wheelchair-entering-the-platform/1058297106
http://www.thinkstockphotos.com/image/stock-illustration-neck-pain-from-smartphone/504005450
http://www.thinkstockphotos.com/image/stock-photo-fitness-sexy-woman-showing-abs-and-flat-belly/868086364
http://www.thinkstockphotos.com/image/stock-photo-businesswoman-suffering-from-backache/614422278
[♪ INTRO].

Hey, you! Sitting there all slouchy!

You gotta fix that posture and straighten out your spine. Well, maybe not completely. Your spine has all these curves in it, so it’s not really straight in the first place.

Actually, with how your spine is naturally curved, how do we even know what good posture is? Turns out, it’s pretty difficult to define. But we do know that some types of bad posture aren’t so great for your health.

And it all has to do with your spine. The spine is one of the most important structures in the human body. It serves as the central support, and it protects the nerves in your spinal cord, allowing your brain to communicate with your muscles and organs.

That’s why it’s so important to take care of your spine. If you don’t, there can be drastic consequences. A massive 2010 study on the Global Burden of Disease estimated that lower back pain causes more global disability than any other condition, affecting nearly 1 in 10 people worldwide.

To understand what causes this sort of back pain, and how posture fits into the picture, you have to understand the shape of your spine. Your spine isn’t perfectly straight. The bones, which are called vertebrae, aren’t stacked neatly on top of one another.

Instead, your spine is curved in an S shape, so the load from your torso is centered directly over your hips. Two parts of the spine curve outward like a turtle shell. Physiotherapists call this kyphotic curvature.

These sections are also called primary curves, because they have the same shape from fetal development to adulthood. But you also have secondary curves, which start kyphotic and slowly change after birth until they curve the other way, which is called lordotic curvature. The neck starts to switch when an infant can lift their head, and the lower back takes shape when they begin to walk.

These secondary curves shift the center of mass of a child’s head and torso over their hips and feet, which makes balance easier while standing. Now, these spinal curves can also change in adulthood. For instance, when someone is pregnant, their lower back will become more lordotic to account for the weight of the fetus.

In addition to bigger curvature, certain regions of your spine also have some subtle lateral curves and rotation to account for the all the organs you’re hauling around. Interestingly, people with a rare condition called dextrocardia have hearts on the right side of their torsos, like a mirror image. And they also have mirrored spinal curves to account for the different weight distribution.

All this to say, your spine is clearly supposed to be curved in certain ways. But unfortunately, there’s not a gold standard for posture to accommodate these curves. For starters, many claims about sitting with proper posture aren’t universally supported or strongly backed by science.

For example, simply changing your sitting posture doesn’t seem to have a major impact on your baseline metabolism. So you won’t be able to get shredded just from sitting at your desk in a certain way. To make things even more complicated, many physiotherapists don’t agree on what the “best” posture should look like.

So these days experts are more likely to suggest regular movement and varying posture. You may have noticed that standing desks have become pretty popular. And on its own, extended standing hasn’t been shown to be any better than extended sitting.

But mixing up your daily routine with sitting, standing, and walking has been found to reduce the incidence of lower back pain in some people. However, it’s also important to acknowledge that some people, like those who use wheelchairs, may not be able to adjust their posture that way. Studies have shown that providing lower back support can increase wheelchair users’ lung capacity and flow.

That can be really important for people who can’t breathe as easily. In addition, wheelchair backs that support spinal curves can give users more vertical range of motion of their arms and make it easier for them to push their wheelchairs forward. So we don’t really have a definitive “best” posture.

But therapists have identified a couple signs of bad posture that can cause back problems, whether you’re sitting or standing. The classic example of bad posture is slouching, and for good reason. Bending forward while you’re sitting reverses the curvature of your lower back, making it more kyphotic.

An easy way to fix this is to scoot to the back of your chair, which helps realign your vertebrae. And despite the wonders of smartphones, like being able to watch YouTube from anywhere, they’ve actually led to a new type of bad posture. So-called “text neck” is what happens when people are using a cell phone or looking at a computer monitor that’s positioned too low, and bend their neck sharply.

This posture fights against the normal lordotic curvature of your neck, and can lead to pain. To avoid this, you might just need to position your screens closer to eye level, so you’re not bending your neck so much and can preserve those smooth spinal curves. Of course, we aren’t doctors here at SciShow.

So if you are concerned about any pain, a physical therapist can prescribe exercise and posture aids to help your muscles and spine. That’s their job, not ours. Sorry if you’re super aware of your sitting posture now, but thanks for learning all about spines and support with us here on SciShow!

And if you want to support our team and help us provide free, fascinating science content every single day, you can go to patreon.com/scishow. [♪ OUTRO].