Mortality rates increase due to extreme heat and cold

July 29, 2014, Helmholtz Association of German Research Centres

Epidemiological studies have repeatedly shown that death rates rise in association with extremely hot weather. The heat wave in Western Europe in the summer of 2003, for example, resulted in about 22,000 extra deaths. A team of researchers led by Dr. Alex-andra Schneider at the Institute of Epidemiology II at the Helmholtz Zentrum München examined the impact of extreme temperatures on the number of deaths caused by cardiovascular disease in three Bavarian cities and included both high and low temperatures in the study.

"Our findings confirm the results of our previous studies, which indicated that the eld-erly and people with pre-existing medical conditions respond particularly sensitively to heat and cold," says Alexandra Schneider. "If you are aware of the effects of air tem-perature on health, you can identify population subgroups who are particularly at risk and take preventive action."

The elderly are particularly at risk

Dr. Susanne Breitner, Dr. Alexandra Schneider and Prof. Annette Peters evaluated almost 188,000 deaths due to between 1990 and 2006 in the cities of Munich, Nuremberg, and Augsburg. They were able to demonstrate that when temperatures rose from 20°C to 25°C or fell from -1°C to -8°C, the number of deaths from cardiovascular disease increased significantly by 9.5% and 7.9%, respectively. While the effects of the heat lasted for one or two days, the effects of cold weather lasted for up to two weeks. Elderly people were most affected. The impact on due to heart failure, arrhythmia and stroke was particularly striking.

The mechanisms that cause these deaths, however, are not yet fully understood. Up to now it has been known that high temperatures, amongst other things, can affect the blood-clotting mechanism (haemostasis) and make the blood more viscous, thereby increasing the risk of thrombosis. Furthermore, as decreasing temperatures have an impact on blood pressure, it can be assumed that there is a link between cold temperatures and the increase in cardiovascular events and stroke.

Preventative programs

"Our findings give an indication of the diseases that are responsible for the observed link between air temperature and death rates, and thus provide a partial explanation as to why some people react more strongly to heat or cold than others and are, therefore, exposed to a greater health risk on hot or cold days," says Alexandra Schneider. "These results are important in order to develop or adapt preventive programs and codes of practice."

The scientists plan to conduct further research into the mechanisms that may be responsible for the health effects observed during cold and, in particular, hot temperatures. They are also interested in possible interactions with air pollutants, which are required in order to predict the effects of climate change on the health of the population, especially in cities and in major conurbations.

Explore further: Hot weather deaths projected to rise 257 percent by 2050s, experts warn

More information: Breitner S. et al. (2014). Short-term effects of air temperature on cause-specific cardiovascular mortality in Bavaria, Germany, Heart, 0:1–9. DOI: 10.1136/heartjnl-2014-305578

Related Stories

Hot weather deaths projected to rise 257 percent by 2050s, experts warn

February 3, 2014
The number of annual excess deaths caused by hot weather in England and Wales is projected to surge by 257% by the middle of the century, as a result of climate change and population growth, concludes research published online ...

Extreme temperatures may raise risk of premature cardiovascular death

September 18, 2012
Extreme temperatures during heat waves and cold spells may increase the risk of premature cardiovascular disease (CVD) death, according to new research in Circulation: Cardiovascular Quality and Outcomes, an American Heart ...

Recommended for you

Women run faster after taking newly developed supplement, study finds

January 19, 2018
A new study found that women who took a specially prepared blend of minerals and nutrients for a month saw their 3-mile run times drop by almost a minute.

Americans are getting more sleep

January 19, 2018
Although more than one in three Americans still don't get enough sleep, a new analysis shows first signs of success in the fight for more shut eye. According to data from 181,335 respondents aged 15 and older who participated ...

Wine is good for you—to a point

January 18, 2018
The Mediterranean diet has become synonymous with healthy eating, but there's one thing in it that stands out: It's cool to drink wine.

Sleep better, lose weight?

January 17, 2018
(HealthDay)—Sleeplessness could cost you when it's time to stand on your bathroom scale, a new British study suggests.

Who uses phone apps to track sleep habits? Mostly the healthy and wealthy in US

January 16, 2018
The profile of most Americans who use popular mobile phone apps that track sleep habits is that they are relatively affluent, claim to eat well, and say they are in good health, even if some of them tend to smoke.

Improvements in mortality rates are slowed by rise in obesity in the United States

January 15, 2018
With countless medical advances and efforts to curb smoking, one might expect that life expectancy in the United States would improve. Yet according to recent studies, there's been a reduction in the rate of improvement in ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.