Hypothalamus

When the hypothalamus is dysregulated by immune imbalance from vitamin D deficiency, it triggers excessive sweating localized to the head as a compensatory response. Vitamin D deficiency triggers an overactive immune system that disrupts the hypothalamus, the brain structure responsible for regulating body temperature and sweating. In a vitamin D-deficient state, the hypothalamus interprets immune hyperactivity as a thermal threat and activates sweating mechanisms during sleep, even without actual fever.