Many people assume that going to bed early guarantees a full night’s rest, only to find themselves awake between 3:00am and 5:00am — the most common window of nighttime wakefulness. This interruption often leaves them tired and unfocused the next day. Surprisingly, waking up during this time isn’t just coincidence; both folklore and science point to deeper reasons behind it.

In Swedish tradition, this period is known as the “hour of the wolf,” a term popularized by filmmaker Ingmar Bergman. Folklore describes it as the darkest point of the night, when nightmares feel real, spirits are strongest, and even births and deaths are said to increase. Expert Birgitta Steene notes that the idea comes from old beliefs linking this time to intense physical and emotional activity.

Science, however, offers its own explanation. Between 3:00am and 5:00am, the body reaches its lowest physiological point: temperature, blood pressure, and metabolism drop as we enter the deepest stage of sleep. For people with anxiety or stress, this natural dip can amplify feelings of worry or unease, making it harder to fall back asleep.

For those who sleep through it, this time is simply the most restorative phase of the night. But for anyone who wakes up during these hours, the combination of biology and heightened sensitivity can feel unsettling. Understanding the “hour of the wolf” helps explain why this specific stretch of night affects so many — whether viewed through the lens of ancient folklore or modern science.