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As temperatures rise, it’s important for people searching for the sun to be safe and responsible outdoors.

According to the Met Office, the UK is expected to experience even hotter weather, which could peak at 30C in central London.

So what exactly are the hot weather health problems and how can they be solved? Health experts share everything you need to know.

Dehydration

For Kiran Jones, clinical pharmacist at Oxford Online Pharmacy, dehydration can occur if you’re exposed to the sun for prolonged periods.

“During a normal day, the recommended amount of fluids is between 1.5 and 2.5 litres (six-eight glasses), but when you’re hot, you sweat more, so more fluid is needed to replenish water loss,” Jones said.

“This can result in you feeling extra thirsty, tired or dizzy, or experience headaches, constipation or even nausea. Plus, you’re likely to have dark, strong-smelling pee.

“To avoid this, maintain a steady flow of fluids throughout the day, ensuring you drink an equal amount of water to other beverages being consumed. And try to limit alcoholic drinks where possible as these can be a diuretic.

“Consider adding oral rehydration sachets to your water bottle at the beginning of each day. As they contain electrolytes like glucose, sodium and potassium, this can help to replace salts and water loss and reduce the effects of dehydration.”

Prickly heat

Excessive sweating can cause skin irritation which presents itself as a heat rash, known as prickly heat.

“This generally presents itself as a small cluster of itchy, prickly red spots in areas such as on the neck, upper chest, in the skin folds and armpits and on the waistline or under breasts,” said Jones.

“To prevent heat rash, try and avoid hot and humid areas, keep hydrated, keep the affected area dry and opt for loose-fitting cotton clothing to prevent overheating or skin irritation from coarse fabrics.

“If you notice a heat rash appearing, visit a pharmacist who can administer the best course of treatment. Recommended products include antihistamine tablets, hydrocortisone cream (not for young children) and calamine lotion.

“If your rash doesn’t improve after a few days, visit your GP for further medical advice.”

Heat stroke

Heat stroke can develop in a few hours and is caused by physical overexertion in hot and humid conditions.

“It happens when your body can’t cool itself down and things such as drinking alcohol, being dehydrated, taking drugs that affect the body’s ability to regulate temperature (sedatives, diuretics, tranquillisers and heart and blood pressure medicines), being obese, or having a disease or medical condition such as cystic fibrosis or problems with your heart, can put you more at risk,” said Jones.

“Symptoms to watch out for include delirium, weakness, dizziness, hot, flushed and pale skin, nausea and vomiting, amongst other things.

“This can be extremely dangerous if not treated immediately and can result in brain swelling, kidney failure, liver failure, metabolic dysfunction, nerve damage or reduced blood flow to the heart.

“So, to avoid this, try and avoid moving around and doing too much, ensure you consume plenty of water or sports drinks, seek shaded areas where possible and opt for lightweight clothes and a hat.

“If you think you or your friends might be experiencing any symptoms, seek medical advice immediately. While you’re waiting for assistance, apply ice packs to the neck, groin and armpits, immerse them in cool water, encourage them to drink water and monitor their breathing.

“Aspirin and paracetamol shouldn’t be taken in the event of heatstroke as they can interrupt the change in the hypothalamic set point caused by pyrogens.”

High blood pressure

According to Jones, high temperatures and humidity can be a bad combination for anyone who suffers from high blood pressure as the hot weather causes the heart to beat faster, circulating twice as much blood around the body.

“Also, some blood pressure medications like beta blockers and diuretics can affect the body’s ability to stay hydrated or respond to high temperatures,” she said.

“Anyone with a history of high blood pressure should drink plenty of fluids to stay hydrated and stay out of the sun where possible in a cool environment, wearing a hat if they are venturing outside.

“They should also monitor their blood pressure regularly during the heatwave. If it’s high or they are experiencing any worrying symptoms like extreme tiredness or confusion, a rapid pulse, excessive sweating, headaches, swelling their arms and legs or nausea, they should seek urgent emergency medical advice.”

Kidney damage 

Carolina Goncalves, a superintendent pharmacist at Pharmica added that kidney damage in hot weather can result from a combination of dehydration and prolonged exposure to high temperatures, which can lead to reduced blood flow to the kidneys and subsequent kidney stress or injury.

“During periods of intense heat, the body sweats heavily to cool itself, losing not only water but also essential electrolytes. This extensive fluid loss, if not adequately replaced, can decrease blood volume, forcing the kidneys to work harder to concentrate urine and conserve water. Consequently, this heightened strain can impact kidney function and increase the risk of developing kidney stones or acute kidney injury,” she said.

“To mitigate the risk of kidney damage in hot weather, it is crucial to maintain hydration by consuming sufficient amounts of water throughout the day.

“Moreover, wearing light, breathable clothing and taking regular breaks in shaded or air-conditioned environments can help regulate body temperature and reduce kidney stress.”

Migraines

Hot weather induces a physiological response known as vasodilation, wherein blood vessels dilate, increasing blood flow throughout the body, including the brain.

“This increased cerebral blood flow can activate specific pain receptors, potentially triggering migraines. The likelihood of this occurring is further enhanced by the dehydration common on hot days,” said Goncalves.

“As the body perspires heavily under high temperatures, it loses significant fluid volume, leading to a decrease in blood volume. This reduction can temporarily impair the delivery of oxygenated blood to the brain, thereby exacerbating the symptoms of a migraine.

“Migraines are most effectively managed using a class of medications known as triptans. This group includes sumatriptan, rizatriptan, and zolmitriptan, among others. These drugs are specifically designed to combat migraine symptoms by constricting blood vessels and blocking pain pathways in the brain.”

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