Causes of heat intolerance and sweating

Sweating is the body's way of releasing heat, but unusually heavy sweating or difficulty cooling down deserves attention. Thyroid overactivity can increase heat production and may occur with a racing heartbeat, tremor, restlessness, or weight loss. Body size, reduced fitness, fever, anxiety, alcohol, and some medicines can also change temperature control. Heat exhaustion can develop after prolonged heat or exertion, especially when fluids are lost. Heat intolerance alone does not identify one condition; the timing, triggers, other symptoms, and medicines provide useful clues.

Move to a cool or shaded place, loosen extra clothing, rest, and drink fluids if you are awake and able to swallow. Avoid strenuous activity until you feel normal. Keep a short record of when sweating occurs, the setting, food or drink beforehand, exercise, menstrual or other hormonal changes, and any new medicine. A clinician may review your medication list and check your thyroid, hydration, and general health. Read more about [Heat Intolerance](/symptoms/heat-intolerance/), [Hyperthyroidism](/conditions/hyperthyroidism/), [Obesity](/conditions/obesity/), and [Heat Exhaustion](/conditions/heat-exhaustion/).

Seek urgent help if heavy sweating comes with confusion, fainting, severe weakness, trouble breathing, chest pain, a seizure, or inability to drink. Heat illness can worsen quickly, particularly after exertion in a hot environment. Arrange a medical assessment if episodes keep returning, occur at rest or during sleep, or are accompanied by palpitations, tremor, unexplained weight change, fever, or persistent thirst.

Could my medicines, thyroid, hormones, or another health problem explain this pattern? Which symptoms should prompt urgent care? Do I need blood tests or a review of hydration and heat exposure?