Fullscreen Video Gets Interrupted Every So Often

This problem occurs regarldess of the media player. Chrome YouTube, Safari YouTube, Quicktime or MPlayeX. I simply start watching the video in full screen and every ~1 minute my Mac exits the fulscreen and shows me the desktop. I have tried quitting all other applications but it didn't help. I am running Mavericks and with the latest updates on a 2013 Macbook Air '13. Any help is greatly appreciated. Thanks.