There’s nothing more relaxing than sitting down with your favorite video game and wasting a few hours.

Or is there? While video games are undeniably fun, they can affect your body in strange ways. That’s not to say that all of the effects are negative—in fact, some may be therapeutic. Here’s what you need to know.

Your vision improves.

Remember when your mother told you to stop playing games, or you’d ruin your eyesight? She was wrong, according to recent science.Action video games improve several aspects of vision, which in turn can improve your ability to read, drive at night, and handle other tasks that require good eyesight. This is partially because games reward players who notice details and take quick action, according to researchers.

Close up of blue eye
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It’s pleasing to be successful in your mission,” said. Daphne Bavelier of the University of Rochester “When you combine rewards with these other [factors], then you get much more learning.”Take that, Mom.

Your body goes into a fight or flight response.

Intense video games can trigger adrenaline and cortisol production. Cortisol is commonly referred to as the “stress” hormone, and it allows you to fight more effectively (or run away more effectively).

Unfortunately, it also suppresses your immune system and makes concentration more difficult. The good news is that your experience with the game will change the effects; if you’re having fun, you’ll enter a state of positive stress called eustress, which is generally beneficial. If you’re frustrated or if you’ve been playing games for too long, you’ll experience distress (the scientific version, not the kind of distress that princesses feel when they’re locked in towers).

Hand sticking out of water
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That can prevent you from getting good sleep, change your appetite, cause muscle tension, stimulate headaches, and make you more irritable. Taking frequent game breaks can help you avoid distress.

You can become more aggressive.

Let’s be clear: Adults can handle violent video games. Kids can’t. An article from Craig A. Anderson and Brad J. Bushman of Iowa State University looked at dozens of studies to determine whether violent video games increased aggressive tendencies. Perhaps unsurprisingly, they found a correlation between violent video games and real-life violence.

[picture of angry gamer]”High video-game violence was definitely associated with heightened aggression,” the article reads. “Violent video games increased aggressive affect in males and females, in children and adults, and in experimental and nonexperimental studies, suggesting that violent video games may also increase aggression by increasing feelings of anger or hostility.”

Wolf growling
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Now, adults may have the psychological tools to combat this effect, but parents should be careful to steer kids towards more wholesome entertainment.

Video games can distract you from pain and curb repetitive behaviors.

A paper by Mark Griffiths, a professor of gambling studies, notes that video games have exceptional potential for pain management therapies.

“The degree of attention needed to play such a game can distract the player from the sensation of pain, a strategy that has been reported and evaluated among paediatric patient,” Griffiths wrote. “One case study reported the use of a handheld video game to stop an 8 year old boy picking at his face.”

Hand holding video game controller in front of TV
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The boy was given a handheld game, which distracted him from his pain until his face had a chance to heal. Griffiths writes that video games deserve more consideration for pain therapies, although he also notes that “long-term studies of the course of video game addiction” should also be a priority.