Patient information · Urgent care
Heat exhaustion and sunburn
cooling down, and knowing when it has gone too far
Heat exhaustion is unpleasant but recovers with cooling and fluids. Heatstroke is a medical emergency and can be fatal. The dividing line is confusion or a change in behaviour — and someone who has not improved within thirty minutes of cooling needs an ambulance.
Call 999 — this is heatstroke — if someone
- is confused, agitated, slurring words or behaving oddly
- has a seizure, or loses consciousness
- has very hot skin that is no longer sweating
- has a temperature of 40°C or above
- is breathing very fast or has a racing heartbeat
- has not improved after 30 minutes of cooling and rest
While waiting for the ambulance, move them somewhere cool, remove outer clothing, and cool them with cold water on the skin, wet cloths and fanning. Cold packs in the armpits and at the neck help. Do not give anything to drink if they are drowsy or confused. Do not go to the emergency department by car if they are seriously unwell — call 999.
Heat exhaustion
Heavy sweating, tiredness, dizziness, headache, feeling sick, cramps, pale clammy skin, a fast pulse and intense thirst. The person remains alert and orientated — that is the key difference from heatstroke.
- Move them somewhere cool — indoors, or into shade.
- Lie them down and raise their legs slightly.
- Cool the skin: loosen clothing, spray or sponge with cool water, fan them, and put cold packs under the armpits or on the neck.
- Give plenty to drink — water, or an oral rehydration solution or sports drink if there has been heavy sweating.
- Stay with them and watch the clock. They should feel better within 30 minutes. If not, call 999.
Who is most at risk
Babies and young children, adults over 65, people with heart or lung conditions or diabetes, those taking diuretics, beta-blockers, antihistamines or antipsychotic medicines, people doing physical work or sport in the heat, and anyone who has been drinking alcohol. Check on elderly neighbours and relatives during hot weather — they often do not feel thirsty and may not notice they are overheating.
Staying safe in hot weather
- Drink regularly through the day, before you feel thirsty. Watch for dark urine as a sign you are behind.
- Stay out of the sun between 11am and 3pm, when it is strongest in the UK.
- Keep curtains closed on sun-facing windows during the day and open windows at night when it is cooler.
- Avoid strenuous exercise, alcohol and heavy meals in the heat; shift exercise to early morning or evening.
- Never leave anyone, particularly a child, in a parked car — the temperature inside can become lethal within minutes.
Sunburn
Sunburn appears within a few hours and peaks at around 24 hours. Skin becomes red, hot, sore and tender, and may blister and later peel.
Do
- Get out of the sun and stay covered until it heals
- Cool the skin with a cool shower, bath or damp flannel
- Apply aftersun, calamine or a plain unperfumed moisturiser
- Take paracetamol or ibuprofen for the pain
- Drink extra fluids — sunburn dehydrates you
Do not
- Do not burst blisters — they protect the skin underneath
- Do not use petroleum jelly, butter or oily preparations on burnt skin
- Do not use products containing local anaesthetic on large areas
- Do not let the area be exposed to the sun again until fully healed
- Do not apply ice directly to burnt skin
Seek medical advice for sunburn if
- the skin is blistered over a large area, or the face is severely affected
- there is fever, chills, dizziness, headache or nausea — this suggests heat illness as well as skin damage
- the burn involves a baby or young child
- the skin shows signs of infection — increasing pain, spreading redness, pus
Protecting your skin
- Use sunscreen of at least SPF 30 with 4 or 5 star UVA protection. Apply generously 30 minutes before going out and again just as you go out.
- Reapply every two hours, and immediately after swimming, towelling or sweating, even if the product says it is water resistant.
- Most people apply far too little. An adult needs around six to eight teaspoons to cover the body.
- Cover up with a wide-brimmed hat, sunglasses and close-weave clothing — more reliable than sunscreen alone.
- Babies under six months should be kept out of direct sunlight entirely.
- Darker skin is less likely to burn but is not immune, and sunscreen is still needed.
Sunburn is skin damage that accumulates. Episodes of burning, particularly in childhood, meaningfully increase the lifetime risk of skin cancer. If you notice a mole that is changing in size, shape or colour, is itching or bleeding, or simply looks different from your others, book a skin lesion and mole check with our dermatology team.
Skin and mole checks, same week
Same-day appointments most days, seven days a week, 9am–7pm, on Whitechapel Road.
Tower Bridge Hospital London
97–99 Whitechapel Road, London E1 1DT
WhatsApp 07903 284 189
info@mhwclinic.co.uk
Open Mon–Sat, 9am–7pm (closed Sundays until September)
In an emergency
Call 999, or go to the Royal London Hospital Emergency Department, Whitechapel Road, London E1 1FR.
When we are closed and it is not an emergency
Call NHS 111 or visit 111.nhs.uk.