What are the Effects of Cold Temperatures on our Health?

[This article was published in Catalan in Espai Salut, a bulletin published by the Diputació de Barcelona]

These days, everyone is talking about the weather, given the recent spell of considerably cold days. According to data from the Catalan Meteorological Service, the feeling of cold in these first weeks of the year is further pronounced by the relatively warm temperatures during the month of December in most of Catalonia. 

And when the cold arrives, so do several directly-related diseases such as the flu, which entered its epidemic phase in mid-January. However, cold temperatures affect our health in many other, less widely-known, ways. To better understand the impact of cold temperatures on our health, we must remember that, when exposed to cold, our body reacts with a series of changes to maintain a stable temperature around 37°C, typical of normal and healthy situations. Some of these changes are an increase in blood viscosity and in blood pressure and heart rate, among others. All this adds stress to our body, which can lead to severe health problems among the most vulnerable.

When exposed to cold, our body reacts with a series of changes to maintain a stable temperature around 37°C, typical of normal and healthy situations

Numerous studies have related exposure to cold temperatures with an increase in mortality. In a study performed in 13 countries, the authors concluded that 7% of deaths were due to cold. In the case of Spain, also included in the study, cold temperatures accounted for 5.5% of reported deaths. The main causes of cold-related deaths are respiratory and cardiovascular diseases, but also diabetes or mental disease. Extreme cold episodes are also responsible for an increase in hospital admissions, particularly for respiratory and cardiovascular causes. 

But not everyone suffers from cold in the same way. Older people are among the most vulnerable, due to their physical condition and the fact that they often suffer from other diseases. In addition, drugs consumed by these individuals sometimes alter the mechanisms that regulate body temperature. A study performed in Barcelona revealed a 25% increase in mortality among people over the age of 65 on days when cold temperatures are registered.

Furthermore, the socioeconomic level plays an important role on the health impact of cold temperatures. Energy poverty has recently become one of the key criteria to define the most vulnerable populations. Poorly insulated households in Southern Europe have more difficulties in maintaining a correct indoors temperature. Another vulnerable group is the working population. A study published last year showed that the risk of work accidents increased 4% on extremely cold days. People working outdoors suffer most from the consequences of cold temperatures.  

The socioeconomic level plays an important role on the health impact of cold temperatures. Energy poverty has recently become one of the key criteria to define the most vulnerable populations

Despite the predicted rise in temperatures due to climate change, extreme cold episodes are expected to occur repeatedly in the following decades. Although some studies suggest that cold-related mortality will decrease with an increase in global temperatures, this is not evident since it depends on many other factors such as acclimatization to warm temperatures (whereby occasional cold episodes could have a greater impact), improvements in infrastructure, or management of energy poverty.

Therefore, with the arrival of cold days, we need to be aware of the health risks and protect those most vulnerable.