Deaths are down to over-heating

Hot weather often leads to an increased death rate

Air pollution is wrongly blamed for many of the deaths that occur during spells of hot weather, research suggests.

A study by University College London found the more fundamental problem is that too many people fail to keep themselves cool during a hot snap.

The researchers found that long runs of successive hot days were particularly associated with higher death rates.

The study is published online in the journal Environmental Research.

The basic message of 'keep cool when the weather is hot' seems to be being drowned out by exaggerated concern over air pollution Professor Bill Keatinge

In 2003, about 27,000 people across Europe died directly because of the heat.

Within England, there were 2,000 excess deaths - 85% of which were among people aged 75 and over.

The UCL team examined death rates for people over the age of 65, who suffer most from extreme heat.

They found that death rates among this group rose progressively as the temperature climbed past 18C.

The research also showed that death rates rose more as temperatures climbed in early summer than in late summer.

This suggests that people become more adjusted to heat as time passes.

Pollutant levels

High levels of pollutants such as ozone and particulates tended to be associated with sunshine, and high particulates and sulphur dioxide with low wind, both of which can increase heat stress.

The UCL study revealed that most analyses would attribute up to half of the mortality to the pollutants.

But the researchers say these studies have not taken into account factors such as adjustment to heat in late summer, and the effect of sunshine and wind.

They conclude that, contrary to earlier reports, pollutants played little part in the rise in deaths associated with hot weather in the period analysed.

Researcher Professor Bill Keatinge said: "Ozone, particulates and sulphur dioxide have been fingered as the culprits when hot weather is more likely to have caused the deaths.

"On hot days, older people are more likely to be dying from heat stress than from air pollution.

"The basic message of 'keep cool when the weather is hot' seems to be being drowned out by exaggerated concern over air pollution."

Long periods dangerous

Professor Keatinge said runs of successive hot days were particularly dangerous.

"The fact that deaths were higher in early summer rather than late summer suggests that some people were unprepared for the hot weather and may not have taken the necessary precautions to keep cool.

"The heat wave in France in 2003 which killed 14,000 people was an unfortunate example of what happens when people are not prepared for hot weather.

"Even Britain, which has around 800 heat-related deaths in an average summer, had more than 3,000 in the exceptionally hot summer of 2003.

"Global warming may well produce runs of hotter days than have ever been experienced here before, and we need to be prepared for that happening in the UK with little warning."