By Gabrielle Olya
November 11, 2016 08:44 AM
Jon Kopaloff/Filmmagic

If you’re like most Americans, a good portion of your day is spent sitting at a desk, which can lead to back pain.

Celebrity physical therapist Karen Joubert — who has helped Jennifer Aniston, Cher and Serena Williams heal their body aches — says it’s important to take measures to prevent the pain that can come from sitting at a desk for hours on end.

“If you have a job where you know you’re going to be sitting all day, it’s important to do preventative exercise,” she tells PEOPLE. “It’s up to you to be proactive.”

Here are a few simple things you can do to prevent desk-related back pain:

1. Take notice of how your desk is set up and adjust as needed.

“Make sure your feet are on the floor, your back is up against the chair, and your computer screen is eye-level,” says Joubert.

2. Whether you have a standing or sitting desk, make sure you shift positions every 20 to 30 minutes.

“We really should never be in a sustained position – either sitting or standing – for more than 30 minutes because you start to stress out the spine, the muscles, the ligaments,” says Joubert. “It’s always good to remind yourself every 20 to 30 minutes to just get up and stand. Walk around and take a couple of deep breaths. Stand against the wall, put your heels against the wall, your butt against the wall, shoulders against the wall, head against the wall, and open up your palms.”

Joubert explains that standing against a wall for a couple of minutes “gets you out of that forward, curl posture that you get into at your desk. You want to undo any position that you’re in for a long time.”

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3. Stop slouching and focus on improving your posture.

“Pull your shoulder blades towards your back pants pockets and sit up,” says Joubert, who explains that having correct posture “engages your abdominal wall. You can breathe better, it’s taking less energy, and you’re even much more productive at work.”

4. When you have pain, listen to your body. 

“Pain is telling you that you’re doing too much of something or not enough of something,” says Joubert. In order to appropriately treat pain, you must figure out the cause first, as stretching and other movements can be harmful if you have a pre-existing back condition that you are unaware of.

“The first step is to seek out a good physical therapist,” says Joubert. “Is your back pain because you have a pinched nerve you haven’t taken care of? Or a pulled muscle? Is it because you aren’t active? You want to figure out how to manage that.”