In virtual reality, it's all too easy to lose track of time. Scientists are now trying to discover why.

Playing video games in VR can make time feel compressed, according to new research. The study found that participants who played the virtual reality version of a game first played an average of 72.6 seconds longer before feeling like five minutes had passed than students who started on a conventional monitor.

“Research suggests that perception relies on bodily signals such as our heart rate,” Nick Davidenko, a scientist at the University of Santa Cruz and one of the study’s authors, said in an email interview. “In virtual reality, we often don’t have a visual representation of our own bodies, and this lack of body awareness can lead us to miss signals that indicate the passage of time.”

Researchers are trying to understand why VR users lose track of time. In the recent study, time compression was only observed in participants who first played the game in virtual reality. The paper concluded that this was because participants based their judgments of time in the second round on the initial time estimates they made in the first round, regardless of the format.