The Penn Medicine News blog checked in with Yana Banerjee, CRNP, a nurse practitioner in the Penn Sleep Center.

Your room is too hot and bright

To stay cool, fans and air conditioning are common solutions, but also consider sheets with more breathable fabrics, like cotton. Banerjee says while there is no exact temperature that is perfect for everyone, the bedroom should be cool.

As you begin sleeping, your body temperature decreases. Having a room that falls within this temperature range helps your body get to this ideal temperature, which helps prevent restlessness and helps ensure quality rapid eye movement (REM) sleep, (the stage of sleep characterized by the highest brain activity).

Seminal research in 1997 by Alan Pack and David Dinges found that restorative sleep including healthy REM, has strong influence on mood and alertness. Quality REM is key to, pardon the earworm, being shiny, happy, people.