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In Spain, the summer of 2023 was the third warmest since there are official records. Only the summers of 2022 and 2003 exceeded it in average temperatures, according to data from the State Meteorological Agency (Aemet), which counted four heat waves, in the past months of July and August, with maximum temperatures that exceeded 40ºC in much of the territory for several days.

Due to climate change, forecasts show that these waves and extreme heat episodes will become increasingly intense, long and frequent; A horizon that poses innumerable challenges for public health. Because high temperatures influence in multiple ways our risk of getting sick, losing quality of life or suffering an accident at work, as a Spanish research has just shown.

According to their data, the chances of being victims of an accident at work rise significantly during a heat wave. "There are many risk factors involved in occupational accidents. Some have to do with the individual himself and others with the work environment, but the environment to which the worker is exposed is also relevant, "says Ana Santurtún, professor in the Legal Medicine Unit of the Faculty of Medicine of the University of Cantabria and main author of a research that has analyzed the impact of heat waves on occupational accidents in the provinces of Madrid, Barcelona and Valencia between 2005 and 2021.

"In the study we saw that heat waves increase the risk of occupational accidents, mainly in the face of accumulated exposure, that is, not at the beginning of the wave, but mainly in the following days," clarifies the researcher. "For example, in Madrid, after three days of heat we saw that the risk of accident at work rises around 5% and in Valencia it rises by 13% after five days of exposure."

The links that link high temperatures with accidents at work have to do with the way our body manages heat, continues Santurtún. Under normal circumstances, the internal temperature of our organism is not affected by the external environment. Only when environmental temperatures rise does the body set in motion internal mechanisms, such as sweating or vasodilation, that allow excess heat to be managed. However, these mechanisms are finite and do not work well in the face of very pronounced and prolonged thermometer rises.

"Extremely high temperatures, such as in heat waves, can cause saturation of these adaptation processes, increasing the risk of suffering an accident both because of their direct physical effects – for example on the respiratory or cardiovascular system – and indirect, by worsening the quality of sleep or reducing the ability to concentrate, among other factors," indicates Santurtún. In general, it is estimated that above 26ºC the productivity of a worker begins to decline and the chances of cognitive function being affected increase, which increases the risk of making mistakes and an accident.

In the study published in the September issue of the scientific journal Preventive Medicine, the researchers attribute the differences in risk detected in the three provinces to the particularities of the climate of the three regions, to the different levels of physiological adaptation of workers or to the specific sectors involved in the accident. While acknowledging that more studies are needed to clarify why the risk of accident was higher in some areas than in others.

In the period studied, there were 1.7 million occupational accidents in Madrid; 1.5 in Barcelona and 578,000 in Valencia. In the three provinces, the percentage of affected men was higher (65.5% in Madrid; 67.7% in Barcelona and 71.5% in Valencia) and the average age of injured workers was around 40 years. Although with variations, the three regions also shared the category most affected by accidents, which was none other than that related to "production, transformation and storage" processes (28.7% of total accidents in Madrid; 34.2% in Barcelona and 35% in Valencia), followed by accidents in the group dedicated to "installation, maintenance, cleaning, waste management and safety", which, according to the study data, accumulated 21.3% of accidents in Madrid, 20.1% in Barcelona and 17.2% in Valencia.

Increase in accidents

Although August was the month with the lowest number of accumulated accidents -probably due to the fact that in Spain it is the holiday month of many employees-, the researchers found that in the 291 days of heat wave registered in Barcelona between 2005 and 2021, the 276 in Madrid and the 176 in Valencia there was a significant increase in accidents. especially in the days following the start of the weather episode. Although there were regional differences, in all the provinces analyzed the relationship between the arrival of heat waves and accidents at work was clear.

"Over the last few summers society has learned many times through the media of cases of workers who had died while developing outdoor work that involved physical effort in the context of extreme temperatures but it should also be known that there are also numerous accidents that although not fatal, Many times they are serious."

Therefore, in the current scenario and in a scenario in which an increase in extreme temperature phenomena is expected, "it is essential that occupational health and accident prevention plans contemplate the risks that arise," claims Santurtún. And he adds: "We are facing something new and both in our country and in others in the European Union measures are beginning to be implemented."

Last May, Royal Decree-Law 4/2023 came into force in our country, which addresses the prevention of occupational risks in episodes of high temperatures. Among other issues, the new legislation establishes that when work is carried out outdoors and in workplaces that, due to the activity carried out, cannot be closed, adequate measures must be taken for the protection of workers against any risk related to adverse weather phenomena, including extreme temperatures. Likewise, the regulations prohibit the development of tasks during the hours of the day in which adverse phenomena occur for those cases in which the protection of the worker cannot be guaranteed.

"In my opinion, this Royal Decree is a step in the right direction," says the researcher from the University of Cantabria. In any case, the specialist considers that, in addition to legislative changes, "a lot of awareness is needed on the part of workers and employers" of the risks of working under adverse weather. "It is a serious issue on which, of course, progress can and must continue," he insists.

According to Santurtún, the European Agency for Safety and Health at Work recently shared an orientation guide on how to deal with high temperatures in the work environment, recognizing heat stress as a risk not only for workers who develop their professional activity in outdoor environments, but also indoors.

When one thinks of the risks of accidents associated with heat, the first thing that comes to mind is the case of workers who must perform very physical work under a sun of justice. But working, for example, inside a warehouse without adequate air conditioning can also be very dangerous. "In hot conditions, the human body activates acclimatization mechanisms. But there are circumstances in which it is essential to stop, hydrate properly and take shelter in a cool environment, and this must be very clear to workers, "warns the researcher. In that sense, it also claims the importance of good environmental conditions in homes, where, especially as a result of the pandemic, teleworking is increasingly taking place.

"There are many homes that do not have isolation conditions that guarantee the well-being of the population neither in summer nor in winter, and with the increase in teleworking people spend even more time in them. Although different means, such as heating or air conditioning, are used to acclimatize, both the economic effort that its use entails for many families and the environmental impact must be taken into account," he says. "Facilitating the reform of facades would be, for example, a preventive measure in some environments."

In another study published in February of this year in the journal Science of the total environment, the analyses of the Santurtún team confirm that on a global scale, in recent decades occupational accidents have followed adownward trend due to the implementation of prevention plans in companies and public administrations. However, if no action is taken, the manifestations of climate change "could reverse that downward trend" due both to the exposure of workers "to extreme weather conditions and natural disasters and to the psychological impact and uncertainty caused by these phenomena."

The world we live in – and work – is changing. This was also demonstrated by the Covid pandemic, which, among other consequences, changed the way millions of people work by a day. Prevention and occupational health measures must know how to adapt to this changing environment and prepare for the multiple challenges that arise, the researchers claim. Looking to the future, "it is essential to actively involve employers and workers, and the differences in needs in the professional sector must be taken into account – it is not the same to work in construction than in agriculture or the health sector – and of each individual, where age, medical history influence", concludes Santurtún. And he adds a reflection: "Without a doubt, our prevention professionals face a great challenge."