Core Temperature & Sleep Onset

Sleep onset requires core temperature to drop roughly 1°C, achieved by dilating blood vessels in the hands and feet. A bedroom at 18–20°C, a warm shower 60–90 minutes before bed (which paradoxically accelerates heat loss), and breathable bedding all speed onset and increase deep sleep. In hot climates such as the UAE, over-cooled rooms with dry air can fragment sleep instead — pair moderate cooling with humidity around 40–50%.