Summer has finally arrived, with daytime temperatures expected to exceed 30 ° C in much of central and southern England on Friday.
The UK Health Safety Agency (UKHSA) has issued a Level 3 heat health alert for London as well as for the East and South East of England in response, which means that take steps to protect the elderly, those with chronic illnesses, young children and babies. .
Health teams in the Midlands and the South West of England have also been alerted to level 2, which means that there is an 80% chance that temperatures will exceed 30ºC.
So what are the best strategies for staying cool when temperatures rise?
Wear loose clothing and long sleeves
Direct sunlight warms the skin’s blood vessels, sending heat inward to the core and raising body temperature. Babies are especially vulnerable because they have a large skin area in relation to their volume. Wearing loose clothing and long sleeves can help prevent this. It also protects from sunburn (see below).
Cold hands, face and feet
The so-called glabrous skin, which is located on the palms of the hands, the soles of the feet and the upper part of the face, contains a special network of blood vessels dedicated to the rapid management of temperature. Applying cold water or a packet of ice to these areas speeds up body cooling. Wetting the skin, with a cold flannel for example, also helps to remove body heat by evaporation, which is the same reason we sweat.
Avoid cold showers
As counterintuitive as it may seem, a cold shower can help conserve body heat by causing the blood vessels in the skin to constrict. This undermines one of the body’s key strategies for heat loss: bringing blood closer to the surface of the skin so that heat can radiate (hence we look red when we are hot). A longer dip in cold water, such as bathing in a lake, will gradually cool your body, but cold showers are usually quick things. Showering with warm water is best because it will increase blood flow to the skin, increasing heat loss.
Stay hydrated
One of the major reasons why heat waves are so deadly is dehydration. When people lose too much fluid through sweating, the blood thickens, increasing the risk of clots and forcing the heart to work harder. Heavy sweating also alters the balance of sodium and potassium in body fluids. This can affect nerve and muscle cells, putting more pressure on the heart. The most important thing is to drink regularly throughout the day, avoiding caffeine and alcohol, which can cause you to urinate more often. Don’t rely on thirst, which can be an unreliable indicator of hydration status.
Keep curtains and windows closed during the day
This is especially important for south-facing rooms, where the sun shining through the windows will transform your surroundings into a greenhouse. As a general rule, windows should be kept closed when it is cooler indoors than outdoors, usually when the day is warmer, but should be opened when the daytime temperature drops in the evening and during the night.
Look for green spaces
People are looking for shade in Brockwell Park, London. Photography: Dan Kitwood / Getty Images
Trees and plants absorb water through the roots and emit it through the leaves through a process called transpiration. This cools your immediate environment, as the heat from the surrounding air causes this water to evaporate. Studies suggest that suburban areas with mature trees are 2-3ºC cooler than suburbs without trees. Trees also provide much needed shade.
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Avoid sunburn
No one wants puffy skin and a blister, but sunscreen should be your last line of defense against the sun, instead of your first. Instead, using the shade when the UV index is at its peak, usually between 11 a.m. and 3 p.m., cover your skin with clothing and protect your head, neck, and face with goggles. sun and a wide-brimmed hat. If sun exposure is unavoidable, opt for sunscreen with extensive UVA and UVB protection. Sun protection factor (SPF) only refers to UVB protection.
“We recommend a sunscreen with a minimum SPF of 30 and good UVA protection,” said Dr Tanya Bleiker, President of the British Association of Dermatologists. “The sunscreen should be applied generously and reapplied every two hours, after swimming, exercising or any other activity that may rub or wash it.”