Addicted to your phone?  It could be ruining your sleep, experts say.

A new study by frontiers in Psychiatry investigated college students between the age of 18 and 30. The researchers found that nearly 40% were “addicted” to their smartphones.

“It is important to note that smartphone addiction has several terms of reference including “nomophobia,” “problematic smartphone use,” and “smartphone dependence,” the original research article by frontiers in Psychiatry states.

The more students who used their phones, the worse their quality of sleep. Experts say phone use disrupts the body’s natural sleep clock, or ‘circadian rhythm’.

They recommend putting the phone away at least one hour before bedtime.