18 July 2013
Last updated at 05:24 ET
The heatwave warning has been raised to “level three” by the Met Office for south-west England and the West Midlands.
The move brings those regions in line with the South East and London, where level three warnings remain in place.
The warning alerts healthcare services to help those in high-risk groups such as the elderly and young children.
Wednesday was the hottest day of the year, with 32.2C recorded at Hampton Water Works in south-west London.
Continue reading the main storyHow to stay safe in the sun
Hot weather poses a real danger to health.
The very elderly and the seriously ill are most at risk but people at the peak of physical fitness can still succumb, particularly if they are under extreme physical exertion.
The main threat is dehydration – as we overheat we can soon lose more fluid than we take in.
The body can no longer cool itself and our core temperature, which should be a stable 37C, rises.
At 40C the cells inside the body begin to break down and the body starts to malfunction.
It even stops being able to sweat, leading to more overheating.
The heart rate and breathing rate speed up and the person may fit, hallucinate or become unconscious.
Heatstroke is a medical emergency that needs urgent treatment.
South-west England was issued a similar warning last week, alongside Yorkshire and the Humber – where temperatures have eased to allow a level two warning.
Alerts are triggered when threshold temperatures have been reached for one day and the following night, and the forecast for the next day has a greater than 90% confidence level that the day threshold temperature will again be met.
The threshold temperature for south-west England and the West Midlands is 30C, while for the South East and London it rises to 31C and 32C respectively.
Scotland and Northern Ireland are not included in the alert system.
It is the UK’s first prolonged heatwave since 2006, with six consecutive days of temperatures above 30C (86F).
Set to continue
The warm weather is set to continue into next week with temperatures in the high 20Cs at the weekend before rising to 30C and beyond next week – bringing with it an increased risk of thunderstorms.
Public Health England (PHE) officials have advised people to stay cool, drink lots of cold fluids and keep an eye on those they know to be at risk.
Dr Angie Bone, heatwave plan leader for PHE, said: “In this continued hot weather, it’s important to remember that high temperatures can be dangerous, especially for people who may be vulnerable such as older people, young children and those with serious illnesses.
“During very hot weather, pregnant women and people who have chronic illnesses, including cardiovascular, respiratory, renal conditions, diabetes or Parkinson’s disease, may experience discomfort if indoor temperatures are particularly hot and in using public transport.
“Employers should ensure indoor areas are kept cool and consider allowing these individuals to travel to or from their place of work during cooler, or less busy, times of the day. For those working or exercising outdoors, strenuous physical exertion during the hottest part of the day should be kept to a minimum.”
Warning signs
Mike Tipton, professor of human physiology at the University of Portsmouth, told BBC Radio 5live that the warning signs should be evident.
He said: “As soon as people start to feel anything like light-headedness, feel that they’re hyperventilating, if they’ve got a very rapid pulse, if they start to feel pins and needles in the fingers and around the limbs, slightly nauseous maybe, headaches, then really they need to stop any activity they’re engaged in, move to the shade, sit down or lay down, preferably get help as well.”
Jonathan McShane, from the Local Government Association, says councils are doing their bit to tend to those who may need extra assistance.
On 5live, he said: “Social workers, care workers, people who deliver ‘meals on wheels’, as part of their daily routine they’re now doing an additional check to ensure that people are coping in the heat and they’re staying hydrated and giving them some advice about how they can stay well and comfortable in the extreme weather.”
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