By clicking a retailer link you consent to third-party cookies that track your onward journey. If you make a purchase, Which? will receive an affiliate commission, which supports our mission to be the UK's consumer champion.
How to deal with heat rash and sunstroke
Hot, sunny weather may be a cause for celebration after an extremely wet winter but it can also impact your health.
Whether it's a UK heatwave or you're off to a summer holiday spot abroad that's experiencing sustained high temperatures, it's important to be aware of the risks.
With increasingly unpredictable temperatures – and record highs – it's easy to get caught out.
Dr Adrian Boyle, president of the Royal College of Emergency Medicine, says: 'We know that climate change is making our summers hotter, and society needs to acknowledge and be alert to the serious health risk that extreme heat presents.'
Here's what you can do to stay safe when things hot up.
Eat well, live better and stay healthy: get our free monthly food and health newsletter for the latest insights and advice
Stay safe in the heat
The best treatment is prevention, so be prepared.
If you're heading to a sports event, festival, beach or know that you'll be outside for much of the day, check the forecast and plan accordingly, with ways to cover up and plenty of hydration.
Dr Matthew Booker, St John Ambulance associate medical director, advises the following simple steps:
- Avoid the midday sun Stay out of the sun at peak times, usually between 11am and 3pm, and seek shade instead. If it's unavoidable, such as if you're in a stadium, take a hat and sunglasses, and take plenty of breaks in the shade.
- Keep well hydrated Drink plenty of water or non-alcoholic fluids, little and often if you can. Keep a water bottle close to hand so you don't forget to stay topped up. Insulated bottles will keep your water cool for longer, so are a better bet than plastic.
- Wear a wide-brimmed sun hat or cap This will keep the sun off your face and neck and help to prevent you overheating.
- Use sunscreen This should be a minimum broad-spectrum SPF30 and should be regularly reapplied.
If the weather is particularly hot where you are for a sustained period, be sure to check in on any relatives or neighbours who may be more vulnerable to heat-related illnesses, ensuring they have ways to keep hydrated and cool.
At home, keeping curtains or blinds closed in sunny rooms during the day can help to keep the house cool. Switch to a simple bed sheet or summer duvet and wear light, breathable clothes.
For more advice on keeping cool at home, see our guide to air conditioners vs electric fans.
Best reusable water bottles: our eco-friendly options that are robust and easy to use
Heat rash: what it is and how to treat it
Heat rash (also known as prickly heat) is usually harmless, and should clear up on it's own within a few days once you're out of the sun.
It occurs when the sweat glands get inflamed or blocked and the trapped sweat produces tiny red spots, blisters or bumps that make the skin feel itchy, prickly or like it's burning.
Treatment focuses on keeping cool and hydrated, staying away from excessive heat, taking a cool bath or shower, applying cold ice packs wrapped in a tea towel for up to 10 minutes, drinking lots of water and wearing loose cotton clothing to allow body heat to escape.
A pharmacist or healthcare professional may suggest using calamine lotion, antihistamine tablets or hydrocortisone cream (not for under-10s or if you're pregnant) to relieve the itching. For more advice, see the NHS guide to heat rash.
It's worth taking stock of what skin products you've used if you get it for the first time after using something new. Some alcohol-based clear sprays for example may aggravate or trigger it.
What childhood rash is this? Our gallery guide runs through some common options and how to tell them apart
How to manage sunburn
- Seek shade Cover sunburnt skin with light, loose clothing.
- Cool the skin down for 10 minutes Use a damp towel or have a cool shower or bath (never ice or ice packs)
- Drink cool water Sunburn draws fluid to the surface of the skin so drink to replace it and to accelerate healing.
- Use aftersun or calamine lotion to soothe the burn Avoid standard moisturisers, as these tend to be thicker and less watery than aftersun, and may stop heat and sweat from getting out by blocking pores.
- Take a painkiller Paracetamol or ibuprofen can help if the burn is particularly painful.
- Know when to seek advice Consult a pharmacist or doctor if the skin has blistered or swollen, or if you're feeling generally unwell. Always seek medical advice if your baby or young child has sunburn. Find out more in the NHS guide to sunburn.
Prevention is better than cure, so make sure you are using a good quality sunscreen that will protect you from burning and applying it properly.
Top sun creams for 2023: see our Best Buys, plus those to avoid
Heat exhaustion vs heatstroke: how to treat it and how long it lasts
Sweating is the body's way of keeping us cool, but if we're out in the heat for long periods the slow but sure loss of water and salts can lead to heat exhaustion. Untreated, this can lead to the more serious heatstroke (sunstroke), which requires prompt action.
Heat exhaustion symptoms
- Headache
- Dizziness and confusion
- Feeling or being sick
- Sweating with pale, clammy skin
- Cramps in arms, legs and stomach
- Fast breathing and rapid heartbeat.
If you have heat exhaustion, this doesn't usually need emergency medical help as long as you can cool down within 30 minutes.
Lie down in a cool place with your legs raised and drink water or an isotonic sports drink, with someone keeping tabs on your breathing, pulse and responsiveness. If there's no improvement after 30 minutes, the NHS says to call 111 or 999.
Heatstroke symptoms
- Headache
- Dizziness and discomfort
- Restlessness and confusion
- Hot, flushed and dry skin
- A fast deterioration in how they respond to you
- Racing pulse and body temperature above 40°C (104°F).
If you think someone has heatstroke, NHS advice is to try and keep them cool and call 999.
You can find out more on the NHS heatstroke advice page.
Symptoms of heatstroke in children are similar, but they may also be more irritable.
Best insect repellents – warmer weather means more biting bugs. We've uncovered the products that will keep you protected
Who needs to take extra care when it's hot and sunny?
Some people need to take extra care when it's sweltering. Children, older people, or those with long-term health conditions are more at risk.
Plus, those with:
Skin conditions Exposure to sunlight or UV light can trigger a number of skin conditions, including sun allergy (solar urticaria), polymorphic skin eruption, cold sores and rosacea. Seek advice for any medication that may be suitable, such as antihistamines or steroids, as well as using sun protection and minimising sun exposure.
Migraine and headaches Dehydration can worsen these but a sultry, humid day and rising temperatures can also bring on head pain. The NHS says pressure changes are thought to trigger chemical and electrical changes in the brain, irritating nerves and leading to a headache.
Serious or long-term illness People with conditions such as diabetes, kidney disease, asthma, heart disease, chronic obstructive pulmonary disease (COPD) and Parkinson's disease may find that their symptoms worsen in the heat, and Dr Boyle says people who are frail or suffering from dementia may be particularly at risk because they're less able to respond to their body's warning signs.
Mental illness Researchers found there were more mental health emergencies on the hottest days. Dr Boyle says: 'People experiencing mental ill health – especially those taking anti-psychotic medication – can be disproportionately affected by hot weather.'
Medications that cause sun sensitivity Some medicines, including common antibiotics, oral contraceptives, steroid creams and antidepressants, can result in sunburn-like symptoms, a rash or other unwanted side effects. Professor Claire Anderson, president of the Royal Pharmaceutical Society, says: 'You can reduce your risk of photosensitivity by staying out of direct sunlight, protecting yourself with a high factor sunscreen, and covering up with long sleeves, trousers and a hat.'
On medication? Here's why you need to be proactive about managing it
