The elderly and the very young are more at risk physiologically of suffering the effects of a heatwave. When the ambient temperature is higher than skin temperature, the body cools by sweating. This is a mechanism may be impaired in the young children and the elderly. In the elderly thermoregulation (controlled by the hypothalamus) can also be impaired.
Young children and babies tend to have core temperature which rise and fall faster during infection and dehydration.
In the elderly, cardiac and respiratory problems can be exacerbated as more blood is circulated to the skin in order to improve cooling. Increased air pollution during heatwaves can also cause problems for those with respiratory conditions.
Heatstroke occurs when the body’s core temperature remains at the increased level of 40˚C for 45 minutes or longer. Symptoms include hot, dry skin, nausea and/or vomiting, drowsiness, fatigue, nocturnal insomnia, convulsions, unconsciousness confusion.