Hot UK Summer 2026: 10 Health Risks and How to Stay Safe

Dehydration occurs when the body loses more fluid than it takes in. During hot weather, sweat rates increase dramatically, and many people — particularly the elderly — do not feel thirsty until dehydration is already moderate.

• Drink water regularly — do not wait until you feel thirsty
• Aim for pale straw-coloured urine as a hydration marker
• Avoid excessive alcohol and caffeinated drinks
• Eat water-rich foods: cucumber, watermelon, tomatoes

Source: NHS — Dehydration

Heat exhaustion develops when the body overheats and struggles to cool itself. It is serious but, if treated promptly, rarely fatal. Left untreated, it can escalate to heatstroke.

• Move to a cool, shaded or air-conditioned environment immediately
• Loosen tight clothing and apply cool wet cloths to skin
• Drink cool water or an electrolyte drink
• Rest and avoid further physical exertion

Source: NHS — Heat exhaustion and heatstroke

Heatstroke is the most severe heat illness. Body temperature rises above 40°C and the brain and other vital organs begin to fail. Without rapid cooling and emergency care, it can cause permanent organ damage or death.

• Never leave children, elderly people, or pets in parked cars
• Avoid strenuous outdoor activity between 11am–3pm
• Stay hydrated and in cool environments during heatwaves
• Know the warning signs in others — heatstroke can impair self-awareness

Source: UKHSA — Heat Health Alerts

The body naturally cools during sleep — a process disrupted when bedroom temperatures remain elevated overnight. Persistent poor sleep during heatwaves carries measurable health consequences, including cardiovascular and immune strain.

• Keep curtains/blinds closed during the day to prevent heat build-up
• Use lightweight cotton or bamboo bedding
• Take a lukewarm shower before bed to lower body temperature
• Open windows at night when outside air is cooler than indoors

Source: NHS Every Mind Matters — Better Sleep

High temperatures force the heart to pump more blood to the skin to dissipate heat. For people with existing heart disease, high blood pressure, or older adults, this additional cardiac workload can be dangerous. The WHO has identified cardiovascular disease as the leading cause of heat-related death globally. (WHO)

• Speak to your GP about medication adjustments during a heatwave
• Avoid strenuous exercise during peak heat hours
• Stay cool and well hydrated throughout the day
• Call 999 immediately if chest pain or collapse occurs

Source: UKHSA — Heat Mortality Monitoring Report

Hot weather — especially in urban areas — increases ground-level ozone and particulate air pollution, worsening asthma, COPD, and other respiratory conditions. The Met Office collaborates with UKHSA to provide air quality forecasting, as ozone levels peak on hot sunny days.

• Check daily air quality forecasts from the Met Office or UKHSA
• Keep reliever inhalers accessible and in date
• Stay indoors on high-pollution days, particularly near busy roads
• Avoid exercising outdoors on high-ozone days

Source: Met Office — Air Quality Guidance

The UK’s UV index during summer is frequently rated “High” or “Very High.” Sunburn causes DNA damage to skin cells and significantly increases lifetime skin cancer risk. The NHS notes the UK has over 16,000 new melanoma diagnoses per year, with UV exposure as the primary preventable cause.

• Apply SPF 30+ sunscreen every two hours and after swimming
• Seek shade between 11am and 3pm
• Wear a wide-brimmed hat and UV-protective sunglasses
• Avoid sunbeds — they compound lifetime UV damage

Source: NHS — Sunburn · Met Office — UV Forecast

Heat, dehydration, and bright sunlight are all well-established triggers for headaches and migraines. During a heatwave, these three factors frequently combine simultaneously, making summer a particularly challenging period for migraine sufferers.

• Stay well hydrated — dehydration is a direct trigger
• Wear sunglasses to reduce light-related triggers outdoors
• Rest in a cool, dark room at headache onset
• Apply a cold compress to the forehead or back of the neck

Source: NHS — Headaches

Warm temperatures accelerate bacterial growth — bacteria such as Salmonella, Campylobacter, and E. coli multiply rapidly above 5°C. BBQs, picnics, and outdoor dining are all more common in summer, and carry elevated risk if food safety practices are not followed.

• Never leave perishable food in the sun for more than one hour
• Keep raw meat refrigerated and separate from other foods
• Ensure BBQ meat is fully cooked through — especially chicken
• Wash hands thoroughly before and after handling food

Source: NHS — Food Poisoning · Food Standards Agency

The mental health effects of extreme heat are frequently overlooked but increasingly well-evidenced. Heat disrupts sleep, increases irritability and agitation, worsens anxiety and low mood, and may exacerbate symptoms of existing mental health conditions. Some psychiatric medications also reduce the body’s ability to regulate temperature.

• Prioritise sleep hygiene during hot weather
• Stay socially connected — isolation during heatwaves worsens wellbeing
• Speak to your GP if you take psychiatric medications (some affect heat regulation)
• Contact Samaritans on 116 123 if you are struggling emotionally

Source: WHO — Mental Health & Climate Change · NHS Every Mind Matters