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Health News - Siestas may help to beat heatwaves

19 August 2005 - written by Mark Pownall for Bupa's health information team

Continental-style siestas - which generally involve resting in the heat of the afternoon and working later into the evening - may be needed to help people cope with hotter summers in the UK, experts say. This follows the publication of research predicting that heatwaves will become much more common in future.¹

Are we really getting more heatwaves?

Meteorological Office research has predicted that by the second half of this century, summers like 2003 - the hottest European summer for 500 years - will become the norm.¹ It might make a change from the drizzle, but such extreme heat - with temperatures reaching 35^oC (95 ^oF) and above - can be a risk to health.

What are the risks of excessive heat?

According to the Department of Health, the 2003 heatwave claimed the lives of 2000 people in England and 27,000 people across Europe.²

If you are exposed to too much heat you cannot cool down fast enough and you overheat. You may also become dehydrated. The result can be heat exhaustion or heatstroke, which can have serious long-term consequences to health, including brain damage and death.²

Who is most at risk?

Anyone exposed to extremes of temperature and humidity is at risk. However, the elderly are more likely to suffer the effects of heat. During the 2003 heatwave, 85 percent of deaths caused by the 2003 heatwave were among people aged 75 and over.²

Babies and children are also at increased risk and people who are overweight may overheat more quickly. If you're very active and don't drink enough water, you are at risk of being affected by the heat. Even wearing the wrong kind of clothing can increase your risk.³

Some medical conditions such as diabetes, Parkinson's disease and epilepsy, and some medicines may also increase risk.^{3, 4}

Why are elderly people more vulnerable?

The elderly are particularly at risk of the effects of heat because they may have an illness or may be taking medication that affects their ability to lose heat. Older people are also less able to cope if their breathing and blood circulation system is put under extra stress. The risk increases still further for those who are unable to care for themselves because they cannot control their environment.²

Why are children more vulnerable?

Children are often very physically active, and their system for sweating is not fully developed so it does not work as well. Like older people, they are less able to care for themselves and control their environment.^{3, 4}

What is the difference between heat exhaustion and heatstroke?

When someone is suffering from heat exhaustion, their body is still able to cool itself down through sweating, but it is not losing excess heat fast enough. Those experiencing heat exhaustion are aware that they are too hot and are sweating and flushing.^{3, 4}

Heatstroke is the more dangerous of the two conditions. The body's normal mechanisms for dealing with heat - including sweating and temperature control - stop working. Often, people with heatstroke cannot think clearly and might be confused. Parts of the brain that control temperature may be 'knocked out' and sufferers may actually think they are cold, further fuelling the heat stroke.^{3, 4}

What are the signs and symptoms of heat exhaustion and heatstroke?

There are a number of symptoms for heat exhaustion. You may have feelings of sickness and weakness or experience a headache or an intense, raging thirst. You might have a cramp in the arms, legs or stomach or feel sleepy or confused. A hot, red, dry skin is often an indicator, as is a sudden rise in body temperature. Your heart may beat more rapidly than normal. You may also feel hot and be flushed and sweaty.³ If more severely affected, you might even collapse.^{3, 4}

The symptoms are similar for heatstroke except that you might not be able to think clearly. Sometimes you may not have the ability to lose heat - you might not be sweating, for example. You will almost always be breathing heavily and you will often have low blood pressure. You may also be in shock. Extreme heatstroke - when the body temperature reaches 41.5^oC or above - can damage the brain, liver, kidney and muscles.^{3, 4}

What should I do, if I have any of these symptoms?

For the milder symptoms, rest for a few hours and drink plenty of water or fruit juice. Seek professional advice if you have unusual symptoms during a heatwave or if symptoms get worse or do not go away after a few hours.

How can you reduce your risk of being affected by excessive heat? ^{2, 5}

Listen to the weather forecasts on radio and television- if a heatwave is forecast, try to avoid going out at the hottest time of the day (between 11am and 3pm)
If you do go out, stay in the shade, wear a hat and loose fitting clothes
Take plenty of water out with you
Close blinds or curtains to keep your home cool
At night keep a window open, because night cooling is important in recuperation
Have a cold bath or shower, and splash yourself (especially your face and neck) with water
Avoid excessive exercise - an early sign of heat stress is fatigue.

How else can you reduce the impacts of heatwaves?

Because older people are at particularly high risk of the effects of heat, you can help by checking on elderly neighbours and relatives. Remind them to drink plenty of water. They may need help closing curtains and blinds and opening windows at night.²

Further information

The Heatwave Plan
Department of Health
0800 555 777
www.dh.gov.uk

Help The Aged
0808 800 6565 (Mon-Fri 9am-4pm)
www.helptheaged.org.uk

References

Stott PA, Stone PA and Allen MR. Human contribution to the European heatwave of 2003, Nature 2004; 432: 610-614.
What to do in case of a heatwave. Published: 11 April 2005. Department of Health.
www.dh.gov.uk
Heat-related illness. Patient UK.
www.patient.co.uk
Kunihiro A. Heat exhaustion and heatstroke. Emedicine.
www.emedicine.com
Heat and sun. Meterological Office.
www.metoffice.gov.uk

All pages were accessed on 16 August 2005