The World Health Organisation has issued a caution against relying on electric fans during extreme heatwaves when temperatures exceed 40°C (104°F).
Experts warn that such conditions can render fans ineffective and potentially harmful.
According to WHO guidance, fans function by circulating air and enhancing sweat evaporation.
However, when ambient temperatures rise beyond body temperature, they may instead accelerate heat gain rather than provide relief.
Health specialists explain that in such extreme conditions, hot air blown by fans can increase body temperature, placing additional strain on vital organs.
This can heighten the risk of heat exhaustion, dehydration, and even heatstroke, particularly among vulnerable groups such as the elderly and those with chronic illnesses.
WHO emphasises that electric fans remain useful only when temperatures stay below 40°C.
Beyond this threshold, alternative cooling strategies become essential.
Authorities recommend using air conditioning, seeking shaded or cooler environments, and ensuring adequate hydration throughout the day.
Experts further note that heatwaves intensify health risks by overwhelming the body's natural cooling mechanisms.
Prolonged exposure can impair cardiovascular and kidney function, especially in high humidity or poorly ventilated spaces.
To mitigate these dangers, individuals should adopt comprehensive cooling measures, including wearing light clothing, taking cool showers, and avoiding outdoor activity during peak heat hours.
The advisory underscores the importance of making informed choices during extreme weather, as conventional cooling methods such as fans may fail under severe thermal stress.