Heatstroke First Aid: Why Cold Water is Harmful & What to Do

It is not recommended to throw cold water over a heatstroke victim because sudden cooling can constrict blood vessels and divert blood flow from vital organs to the skin, making heat dissipation more difficult and worsening the heatstroke. Instead, the recommended first aid for heatstroke involves gradually cooling the person by applying cool, wet cloths or spraying them with a hose and fanning them to promote evaporation.