Reddit: Escaping gases. Synovial fluid present in your joints contains oxygen, nitrogen, and carbon dioxide, when you pop, these bubbles escape. This can relieve pressure. Cracking also leads to momentary ligament looseness and relieves tension.
Most importantly, though? Popping triggers the release of local endorphins, which cause a near instant but temporary relief like pain medication making you unaware that your back hurts.
Link: When you are feeling tension in your back and neck, the first thing that you do is attempt to crack it. There is nothing worse than feeling like you are stuck in one place because your back feels like it’s out of place. The reality is when you crack your back you’re not really cracking anything. Rather, you are relieving pressure from your joints. The built up gasses from your joints are actually being released which cause the immediate feeling of relief. This isn’t always good for you and can actually have negative effects when you are stretching your joints beyond their typical range of motion, which can lead to damage if you do it for a prolonged period of time.
WebMD: Yes, its ok to crack your back as long as it feels better. If you feel and pinching or pulling, Stop. Continuing to push at that point you could end up with stretched nerve, pulled muscle, etc. It feels good because throughout the years our spines get stretched and pushed on and overloaded. This causes it to become misaligned, not a lot, just a little here and a little there, and those spots build up gas(I don’t remember the technical word and my Chiropractor’s on Xmas break. But that what the sound you hear when your “popping” your back, the little bubbles of gas bursting and since you’ve also realigned your spine that’s why it feels so good. One word of advice to everyone, as far your neck goes, go easy, even if your a 6’4 240lb dude your neck bones are roughly the same size as the littlest bones in your hand. I also strongly recommend visiting a Chiropractor, if you think that one area feels good from cracking just imagine have every bone in your body realigned, WooHoo!
Fox News: “Cracking or self-adjusting any joint within the body is bad for you if it is done in a habitual manner,” Dr. Christopher Anselmi, a Chiropractor at Hospital for Special Surgery’s Integrative Care Center in New York City told FoxNews.com. “These joints are composed of ligaments, tendons and other soft tissue structures which can wear out over time. Any undue placed on these joints can lead to premature breakdown.”
Although the “cracking” or “popping” noise you hear may sound alarming, it doesn’t mean anything is breaking. Our joints contain fluid and gases like nitrogen and carbon dioxide. When the liquid is put under pressure and force is applied to the joint, the gas exits and creates a “pop-like” sound.
If you’re cracking your back to alleviate tension, Anselmi suggests easy stretches.
“A simple way to stretch a tight back is to get into the shower and stretch your back out gently. After roughly 5 minutes [of showering], flex forward extend backwards, and bend from side to side. Make sure not to bounce or over-do it,” Anselmi said.
Cracking your back may not cause any major damage to your bones and joints, but if you constantly feel the need to do do, you should see a back specialist to determine if you have any underlying conditions.
“If your back pain persists a chiropractor is an excellent choice as a first line of defense for back pain,” Anselmi said. “When a professional manipulates the spine or any joint in the body it is performed in a controlled manner and followed by specific exercises or stretches. This approach ensures attention is given to both the joint and its surrounding tissues.”