Research suggests that sleep loss and anxiety are closely linked, reports Forbes.

One study found that brains of participants who’d experienced even brief periods of sleep deprivation showed greater activity in a complex of “emotion-generating regions of the brain” and reduced activity in “emotion-regulating regions.”

These findings are linked to why people with anxiety disorders often report an explosion of anxiety first thing in the morning. Poor sleep seems to put the brain on-guard by triggering spikes in stress hormones like cortisol, producing an early a.m. “anxiety bloom” even before the day begins.