Usually, sitting down feels good — such as after a hike, a long walk, or an eight-hour shift as a waitress. Sometimes, sitting feels good even after we do it all day long, mostly because we’re used to it (and let’s admit it, a little lazy).

But at a certain point, sitting no longer feels good or necessary when we do it all the time. It begins to feel like our muscles are wasting away and our butts are turning into pancakes. More and more evidence is surfacing about the short-term and long-term risks of constant sitting. Though short bouts of sitting can allow the body to rest and rejuvenate itself, doing it all the time — behind your computer screen at work or on your couch at home — can and will ultimately hurt your mind and body.

The reality is this: It’s not 1965 anymore, and scientists are beginning to realize that office desk jobs are bad for your health. While it may take some time for companies to catch onto this, it’s better for you to take action now on your own before the damage is done.

In the video below, Murat Dalkilinç explains what exactly happens to your body when you’re sitting for long periods of time. If nothing else will convince you to start exercising more and perhaps using a standing desk at work, this video will.

First and foremost, sitting curves your spine as you slouch, putting strain on your spinal cord and ultimately preventing your lungs from getting enough space to expand fully. With your lungs not breathing in completely, you have less oxygen being distributed throughout your body, which is exacerbated due to less circulation when you’re not moving. Less oxygen to your brain ultimately leads to lost concentration. So when you’re sitting, you’re probably focusing less than you would if you were moving around.

This is why research has shown that taking walks — especially in parks and in nature — is conducive to a creative, sharp, and concentrated mind. You may often feel lighter, happier, and more focused the very moment you step outside the office. This is because when your body is moving, so is your circulation, your breath, your “flow” — and the wheels of your mind are turning as well.

Ultimately, our bodies are built for motion, not being couch potatoes. We have to give our bodies what it really needs: physical activity as much as we can.

But there’s hope: Even if your job doesn’t allow you to work outside the office or use a standing desk, even just taking five-minute walks every hour will help unravel the adverse effects of a sedentary lifestyle. Physical activity will lengthen our telomeres, the caps at the ends of chromosomes that are tied to aging and stress — making us live longer, healthier lives.

Learn more about how your body is affected by a sedentary lifestyle, and how you can change it, on the TED website.