During long cold winter nights, our bodies naturally require more sleep and recovery, beyond the simple desire for warmth. Research indicates that people sleep longer and experience deeper sleep in winter compared to summer, even in brightly lit cities, due to the effects of natural light on the body’s biological clock.

Researchers at Charité Medical University in Berlin explain that reduced light exposure increases melatonin, the hormone that signals sleep, making mornings feel less active. Additionally, the longer REM sleep in winter helps restore mental energy and supports psychological health.

Cold weather increases energy consumption to maintain body heat and reduces serotonin production, affecting mood and contributing to winter lethargy or social withdrawal, known as seasonal affective disorder.

Despite artificial lighting, natural sunlight cannot be fully replaced, and blue light from screens may disrupt the circadian rhythm. Experts recommend reducing screen use before bed, exposing the body to morning sunlight, or using medically approved light therapy lamps.

To maintain healthy winter sleep, sleep specialist Nicole Eichelberger suggests keeping consistent sleep schedules, creating a dark and quiet bedroom with moderate temperature, avoiding caffeine and stimulants in the evening, limiting screen time before bed, and practicing relaxation techniques like meditation or deep breathing. Proper sleep is essential for immunity, hormone regulation, and overall heart and brain health.