Officials warn that the heatwave is likely to cause health problems for people in the near future. The UK Health Security Agency has issued a level 3 alert for the south of England on Friday and Saturday.
According to forecasters, Wednesday’s temperatures will reach 28C (82F), in the Midlands and south east England. However, cooler weather is possible further north.
London could have 34C (93F) by Friday and Manchester 30C (30F) by Friday.
People are asked to be vigilant in this unusually hot weather and to pay attention to the most vulnerable people, such as seniors who are most at-risk of heat exhaustion.
Here are the facts about heat and how to keep cool.
The body heat causes blood vessels to expand. This causes lower blood pressure, which makes it harder for the heart to pump blood around the body.
As blood vessels leak, this can lead to mild symptoms like a itchy heat rash and swelling of the feet.
Moreover, sweating can lead to the loss fluids and salt, and, most importantly, the body’s balance.
Combining this with a lower blood pressure can cause heat exhaustion. These are the symptoms:
The risk of developing heart attack increases if blood pressure falls too low.
No matter what season it is, our bodies try to maintain a core temperature of 37.5C.
It is the temperature at which our bodies evolved to function.
As the temperature rises, so does the body’s ability to maintain its core temperature.
It opens up more blood vessels to the skin, causing us to lose heat and start sweating.
The heat loss from the skin is dramatically increased by sweating.
Some tips from the UK Health Security Agency
Experts recommend that you use thin sheets and cool your socks in the refrigerator before putting them on. Then, stick to your bedtime routine.
Heat exhaustion can usually be treated if they can be cooled within 30 minutes.
The NHS advises:
If they don’t recover in 30 minutes, heat stroke will follow.
You should dial 999 immediately if you are experiencing a medical emergency.
Heat stroke patients may not feel the need to sweat, even though they’re hot. They could experience seizures or lose consciousness if their temperature rises to more than 40C.
People may be less able to deal with heat stress due to old age or long-term conditions such as heart disease.
Diabetes can cause the body to lose more water quickly. Other complications can also affect blood vessels and ability to sweat.
Children and people who are less mobile might also be more at risk. People with brain diseases such as dementia can become unaware of heat and unable to control it.
Homeless people will also be more likely to be in direct sunlight. Higher temperatures will also be experienced by those who live in high-rise apartments.
Yes, but it is important to continue taking your medication as usual. People also need to be more careful to keep cool and hydrated.
Diuretics, also known as “water pills”, increase the body’s ability to expend water. They can be used for any reason, even heart failure. They can increase the risk of dehydration at high temperatures and cause imbalances in key minerals.
Antihypertensives, which lower blood pressure, can be combined with blood vessels that dilate to deal with heat to cause dangerous drops in blood pressure.
Certain drugs for Parkinson’s and epilepsy can cause sweating to be blocked and make it more difficult for the body’s cooling process.
If there is excessive fluid loss, other drugs like statins or lithium can be more concentrated in the blood and become more problematic.
High temperatures are responsible for approximately 2,000 deaths in England each year.
These will most likely be heart attacks or strokes. They are caused by straining to maintain body temperature.
Once the thermometer reaches 25C-26C, the death rate increases.
The evidence shows that the deaths are more likely to be due to higher temperatures in spring and early summer than “peak season”.
It could be that we adapt to the heat and start to change our daily behavior.
Evidence from heatwaves past shows that deaths increase very quickly during heatwaves – in the first 24 hours.
Follow James on Twitter.
