When temperatures rise, the human body works hard to maintain a stable internal temperature, typically around 37°C. The primary way it achieves this is by increasing blood flow to the skin and producing sweat. As sweat evaporates from the skin's surface, it carries heat away from the body, helping to cool us down. This natural process is effective, but it requires the body to be adequately hydrated and not overwhelmed by excessive heat.
However, prolonged exposure to high temperatures or insufficient fluid intake can disrupt this delicate balance, leading to heat-related illnesses. The first stage often encountered is heat exhaustion, characterised by symptoms such as tiredness, dizziness, headaches, nausea, excessive sweating, and muscle cramps. NHS guidelines advise moving to a cool place, lying down with feet slightly raised, and drinking plenty of water or a rehydration drink. Failing to address heat exhaustion can lead to more serious conditions.
The most severe form of heat-related illness is heatstroke, which occurs when the body's core temperature rises rapidly and its cooling mechanisms fail. Heatstroke is a medical emergency and requires immediate attention. Symptoms include confusion, a high body temperature (often 40°C or above), hot red skin, rapid breathing, and potentially loss of consciousness. The NHS advises calling 999 immediately if someone shows signs of heatstroke.
While hot weather can affect anyone, certain groups are at a significantly higher risk of serious harm. These include older people, babies and very young children, individuals with chronic health conditions such as heart disease, respiratory problems, kidney disease, or diabetes, and those taking certain medications. NICE (National Institute for Health and Care Excellence) and NHS guidance consistently emphasise the importance for these vulnerable groups to stay hydrated, seek shade, wear light clothing, and avoid strenuous activity during the hottest parts of the day. It is also advised to check on vulnerable neighbours, friends, and relatives.
To mitigate the risks associated with hot weather, general advice includes drinking plenty of fluids, avoiding alcohol, seeking shade or staying indoors during the hottest hours (typically 11 am to 3 pm), wearing loose-fitting, light-coloured clothing, and taking cool showers or baths. Readers concerned about their health in hot weather should always consult their GP or call NHS 111 for advice, as this article does not constitute medical guidance.