Summer is here, and with it comes the annual reminder that our bodies are basically delicate meat machines that don't handle extreme heat all that well. While anyone can feel the effects, the elderly, babies, and young children are especially at risk - because evolution apparently decided that the most vulnerable should also be the least equipped to deal with thermostats gone wild.
Here's what happens when the mercury rises: blood vessels dilate, blood pressure drops, and your heart has to work overtime to keep everything moving. The result? Mild annoyances like heat rash or swollen feet, or if you're really unlucky, heat exhaustion. Symptoms include dizziness, nausea, and a general sense that your body is staging a protest. If blood pressure plummets too far, you might be looking at a heart attack - because why not add a little drama to your summer?
Your body's goal is to maintain a core temperature of about 37°C, whether you're in a snowstorm or a heatwave. To achieve this, it opens blood vessels near the skin and starts sweating. Sweat evaporates, cooling you down - assuming you're not in a humid hellscape where sweat just pools and mocks you. The UK Health Security Agency (UKHSA) suggests checking on older people, those with underlying conditions, and anyone living alone. Also, please don't leave babies, children, or animals in locked cars. It's not a sauna; it's a death trap.
If you spot someone with heat exhaustion, the NHS says move them to a cool place, give them water, and loosen their clothes. If they recover within 30 minutes, great. If not, they might be heading toward heatstroke, which is a medical emergency. Call 999 immediately. Symptoms include a temperature over 40°C, seizures, and - confusingly - stopping sweating even though they're still hot. It's like your body's cooling system just gives up.
Certain groups are more vulnerable: older people, those with heart disease or diabetes (which makes you lose water faster and messes with sweating), children, people with dementia, and the homeless. Oh, and anyone living in a top-floor flat, because physics hates you. Medications can also complicate things: diuretics (water pills) increase dehydration risk; antihypertensives can cause dangerous blood pressure drops; some epilepsy and Parkinson's drugs block sweating; and lithium or statins can become more concentrated if you're dehydrated.
During the 2022 heatwave, when England hit a record 40.3°C, there were an estimated 2,985 excess deaths - the highest ever recorded. Summer 2024 saw 1,311 heat-associated deaths, and summer 2025 had 1,504. Most of these are from heart attacks and strokes caused by the strain of keeping cool. Death rates start climbing once the thermometer passes 25-26°C, though oddly, the deadliest heat tends to come in spring or early summer, not peak summer. Probably because by August, we've all given up and accepted our sweaty fate.