If you're reading this from your desk at work, think about this.  Did you know that the simple act of sitting actually puts physical pressure on your spine?  In fact, researchers say sitting distorts the natural curve of the spine and doing it too long can lead to everything from pinched nerves to herniated discs. 

But there are things you can do to correct your posture.

It only takes 20 minutes for blood to pool into your legs and pressure to build in the spine.  It's one of the reasons why researchers say sitting is one of the worst positions for the body to maintain, but how we sit could be just as big a problem.

One New York researcher found your body can only handle 20 minutes of slouching before it starts to deform your ligaments.  So when it comes to good posture, remember the rule of three:

Sit with your neck forward, your upper back should curve out and lower back should curve in.

Also, your shoulders should be relaxed. 

To give your body a break, stand every 20 minutes.  One Standford researcher says simple stretches such as twisting and turning your head once every hour, helps relieve more tension than yoga once a week.

Posture isn't just about looking good, but is the key to better health.  The American Journal of Pain Management shows posture affects every bodily function from breathing to hormonal production.