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Story Publication logo November 21, 2023

Work at Risk in the Face of Unseasonable Heat


A woman carries a food delivery backpack in the heat

El Surtidor examines how delivery app workers have to deal with extreme heat.

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Multiple Authors

Video courtesy of El Surti.

This report was originally published in Spanish on Below is an English translation.

An experiment with delivery drivers in Greater Asunción, one of the hottest areas in Latin America, reveals health and safety problems due to rising temperatures aggravated by the climate crisis.

A heat wave in January 2022 did not seem unusual for a Mediterranean country in South America that boasts its high temperatures almost as a trademark. It was summer, and in recent years it has become common for the country to break its own temperature records, usually above 40 °C (104 °F) . But a request for solidarity altered the appearance of normality of another heat wave and broke the resignation of the Paraguayan population to this reality that is assumed to be predestined.

“Invite water to your delivery. In a pandemic we helped contain the virus, now we face death in this heat wave that we are suffering.”

The request was signed by the Motorcycle and Related Workers Union (Sinactram). Delivery workers in Paraguay are an emerging force in the economy that became key during the health emergency of 2020 and 2021. The precarious working conditions, such as low incomes, long travel hours and accidents, were known. But, in the midst of insurmountable heat, the request for empathy from customers with a glass of water stood out as unusual and dystopian.

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That January 2022, the Meteorological service recorded that six locations in the country had temperatures above 41.5 °C (106.7 °F) in the shade and exceeded their record high temperatures. The trend suggests that recent decades are warming at an increasingly rapid pace. In the last 40 years, the average number of heat waves in Paraguay increased three times, and there is evidence linking their increased frequency and impact to the climate crisis. Scientists from Argentina, France, the U.S., New Zealand and other countries found that the crisis created by fossil fuel emissions and deforestation made a December 2022 heat wave sixty times more likely than in a world without climate change. And the heat wave that erupted in the winter of 2023 in the region would have been impossible without the impact of human activity on the climate: It was 100 times more likely and between 1.4 °C and 4.3 °C warmer.

A delivery person passes along Santa Teresa Avenue in Asunción, at 12:15 pm. The delivery drivers agree that the large avenues are the hottest places on their routes. Some parts of the capital have become heat islands due to lack of trees and building construction materials that are not suitable for the local climate. Image by Sandino Flecha.

The most visible effect can be seen on the front pages of newspapers and in the news, from fierce forest fires to frequent power outages due to a collapsed service in the face of high energy demand. The impact that is less talked about, but which is already being experienced, is on the work performance of male and female workers. Projections are not encouraging.

By 2030, Paraguay will lose the equivalent of 33,200 full-time jobs in productivity hours because it will not be able to work due to temperatures, four times more than the impact of the heat in 1995. The International Labor Organization (ILO) says its effect on productivity will be perhaps the worst economic consequence of climate change, something linked to health.

Exposure to extreme heat is associated with various problems such as kidney disease, poor sleep, worsening heart disease, respiratory difficulties, deterioration of mental health, as well as an increase in non-accidental and injury-related deaths. In this scenario that resembles scenes from Dune, the deliveries' demand for drinkable water in January 2022 appears as the canary in the mine that anticipates a tragedy to come if nothing is done.

Through public information requests, interviews, temperature measurement days and databases, we gathered evidence that heat already affects the work performance of delivery drivers, something that coincides with the scientific literature on how high temperatures limit work. We also recorded in their accounts that the likelihood of traffic accidents increases on hot days. And our measurements of temperature indices suggest that in certain conditions there is a risk of impact on their health. This research, a co-publication with América Futura of El País, shows that without preventive measures and action by companies and the state, these conditions can lead to short- and medium-term damage and other consequences, even fatal, for a workforce that employs thousands of people.

The many names of heat

The unwanted effect of heat on the body has a name that is scarce in everyday vocabulary: heat stress. But climate change can make it an everyday occurrence. It occurs when people are exposed to heat above what can be tolerated. The body's natural cooling system, which is sweating, begins to fail. Water and salt are lost, and blood vessels dilate, leading to exhaustion, cramps, dizziness, headaches and excessive sweating. This is explained by Marcos Orrego, emergentologist and pediatrician at the Acosta Ñu Hospital. All these symptoms were reported by ten delivery drivers interviewed for this study in November 2022.

Walter Santander, 35, is a self-employed delivery man who works eight to ten hours a day, and although he says he chose this trade because he can manage his schedule, he does not always manage to shelter from the high temperatures in the Central department. He says the heat is at its most intolerable between noon and 4 pm. "As the years go by, the impact of the heat is felt a little more. In previous years it wasn't like that, you could stand it. Now it's not, you feel the heat more because of the asphalt. Physically it exhausts me. It makes my head hurt a lot," he says.

A delivery worker moves along Eusebio Ayala Avenue around noon. Delivery drivers say that between noon and 3 and 4 in the afternoon, they suffer the most from the heat. They report fatigue, excessive sweating, headaches and dizziness, symptoms of heat stress. They have also reported fainting on public roads. Image by Sandino Flecha. Paraguay.

Heat stress can affect mood. Liz Reyes, who worked for apps like Monchis and Pedidos Ya because she couldn't find another job outlet at 25, knows this all too well. "Heat overload irritates you, throws you off your concentration, makes you nervous. Everything upsets you," Reyes says in the interview. Reyes worked every day of the week, including holidays and public holidays, but the income did not exceed Gs. 2,200,000, an amount below the current minimum wage. Reyes supplemented this by working long hours in other services, such as cleaning.

If heat stress is not abated, it can develop into heat stroke, a more serious condition. In practice, it presents itself as an episode Reyes experienced. Reyes was on Route 2 on her way to the city of Capiatá at 5 p.m. when she decompensated on the moving motorcycle. "According to the people who saw me, I went sideways and I literally do not remember anything. The only thing I remember is that I was riding the motorcycle and I felt the lack of air, from the excess heat," she says. "Then I woke up in bed, all in a cast." In addition to the heat, she attributes the accident to lack of rest. She was working 16 hours a day.

Heat stress can also be measured by internal body temperature. We conducted an experiment with five volunteer delivery drivers for seven days in the months of February and March 2023, two months after the December heat wave attributed to the climate crisis. We placed monitors on the body of each to record whether their core body temperature increased during their runs. We designed this measurement inspired by the work of environmental physiologist Andreas Flouris, a professor of physiology at the University of Thessaly in Greece and one of the leading scientific voices in heat and work studies. He leads efforts by governments around the world to adapt labor policies to high temperature conditions.

Science establishes that the body should be maintained at around 37 °C (98.6 °F). In a systematic review and meta-analysis led by Dr. Flouris of 111 scientific papers, collectively covering more than 447 million workers in 40 different occupations, it was found that people who worked a single shift under heat stress conditions showed average core temperature values of 37.6 °C (99.68 °F) .

In our measurement, we recorded that the internal temperature of the delivery persons in all cases exceeded 37 °C (98.6 °F) at times. One delivery reached 37.6 °C (99.68 °F), which according to Dr. Flouris is mild hyperthermia, when the body exceeds the temperature considered normal and loses the ability to thermoregulate.

Marcos Maidana (33) wipes sweat from his face under the meager shade of a palm tree in the capital's corporate hub, lined with tall buildings. The Municipality of Asunción did not respond to a public request for information about its heat adaptation plans. Image by Sandino Flecha. Paraguay.

Delivery drivers do not perform heavy tasks consistently throughout their workdays, and yet we recorded fluctuations tending to increase body temperature. But these isolated results are not conclusive. Flouris suggested to the El Surti team to run the experiment more times to consolidate the data and draw better conclusions.

But when we talk about heat, we're not just talking about core body temperature or air temperature. Another unfamiliar but key concept in occupational heat stress studies enters the picture: the wet bulb temperature index. For many scientists, it is the best way to assess the damage that heat can cause to the human body. This measure of heat stress under direct sunlight takes into account air temperature, wind speed, humidity and solar radiation, meteorological indicators that we accessed through a request for information from the Weather Service and that, for Dr. Flouris, can explain the fatigue, headaches and other ailments reported by delivery drivers as a result of heat.

On five of the seven measurement days, delivery drivers were exposed to high risk and extreme heat risk, according to the calculation of the wet bulb temperature index we made with a Heat Health Organization tool. We found that the risk increased at times after 11 am and before 4 pm. We were also able to confirm that the delivery worker whose core temperature reached 37.6 °C (99.68 °F) was exposed to high and extreme heat risk on the worker's route.

The health risk that delivery drivers face due to the heat

*Siglas en inglés del índice de temperatura del bulbo húmedo
*Wet bulb temperature index
Between February and March 2023, we measured the wet bulb temperature index while volunteer deliveries were being made. This index allows us to assess the risk to health from heat. We used data from the Weather Service and a Heat Health Organization tool to calculate it. We found that workers were exposed to high and extreme heat health risk for several hours, as seen in the graphs of measurement days.

In evaluating the meteorological conditions on the days of the experiment, Dr. Flouris points out two things. First, there are some very abrupt variations in the wet bulb temperature index, which makes him doubt the fidelity of certain data, especially the radiation data. Upon consulting the Meteorological Service, they explained that the variations may be due to the presence of cloud cover or airborne particles such as fog or dust. Officials rechecked some records and assured that the "sharp" reduction in solar radiation on the days of measurement with the deliveries was due to clouds existing at the time of observation.

The other thing the scientist points out is that radiation values above 800 are considered high, and the Meteorological Service recorded numbers above that value for several hours, which translates into sunny, almost cloudless days. Anyone who has to be exposed to that for a long time can have the symptoms the delivery people describe, Flouris explains, and warns that if the air temperature exceeds 37 degrees, the picture can get worse. "Imagine a hair dryer blowing across your face. You won't feel good. That's what a delivery feels like when it's 37 degrees or higher," he says.

The hours of a delivery exposed to high and extreme heat risk

Horario Temperatura °C Radiación w/m2 Velocidad del viento m/s Humedad relativa % WBGT** Riesgo por calor Temperatura central
12:00 35,5 990 4,8 51 32,2 °C Extremo Sin monitor
12:20 35,3 1006 5,7 53 32,2 °C Extremo Sin monitor
12:40 35,9 1021 4,2 49 32,5 °C Extremo Sin monitor
13:00 36,1 938 4,4 50 32,6 °C Extremo 37,09
14:00 36,0 785,9 5,2 49 31,7 °C Alto 36,65
14:50 36,4 629,4 4,6 48 31,5 Alto 36,41
15:20 35,7 542,2 6,0 48 30,5 Moderado 37,32
15:25 * * * * * * 37,57
15:26 * * * * * * 37,6
15:27 * * * * * * 37,63
15:28 * * * * * * 37,64
15:29 * * * * * * 37,61
15:30 35,3 91,1 5,6 49 29 Bajo 37,56
15:40 36,2 459,8 7,1 45 30,1 Moderado 37,43
15:50 35,6 418,6 5,6 48 30,1 Moderado 37,29
*No data available
**WBGT: Wet Bulb Globe Temperature Index
Source: Temperature, radiation, wind speed and relative humidity data from the Meteorological Service / Wet bulb temperature index calculation from Heat Health Organization / Core temperature recorded by Core Body Temperature Sensor / Measurement data taken by El Surti on 03/29/2023.

What to do when the heat risk is high or extreme will depend on the workload and the body's acclimatization. An acclimatized body is one that has been exposed to certain temperature conditions for two to three weeks, explains Flouris. When the heat risk is extreme, if workers are acclimatized, the recommendation is that they work 50 minutes for every 10 minutes of rest and drink one liter of water per hour to stay hydrated. If they are not acclimatized, the suggestion is to work 10 minutes for every 50 minutes of rest, plus one liter of water.

If the heat risk is high, workers such as those on deliveries, who are acclimatized and who perform light work, can make their deliveries continuously but should drink 750 ml per hour. If they are not acclimatized, as occurs at the end of the coldest seasons of the year or during heat waves, an average of 20 minutes of work for 40 minutes of rest and 750 ml of water per hour is recommended.

Dr. Flouris suggests that deliveries wear light colors and that helmets should preferably be white to protect them from high radiation. And he warns that in heat waves and at the beginning of summer seasons, bodies are not usually acclimatized, so precautions such as more rest time between rides should be taken.

Christian Duarte makes a brief stop in the capital's Sajonia neighborhood to hydrate at 7 pm. Delivery drivers work eight to 12 hours a day, even 14. Much of that time they are exposed to heat that is considered a high health risk. Image by Elisa Marecos Saldívar. Paraguay.

But for Emilio José Cañete, no rest is possible. This 33-year-old electrician from the city of Luque also delivers orders by motorcycle, and says that resting because of the heat reduces his productivity, with consequences for his income. "The heat affects … You have to stop repeatedly to look for shade, or hydrate yourself or something. If you are working by application you have to disconnect every so often or if it is an independent work group you have to stop and obviously, you lose trips during the break," says Cañete.

According to the ILO, at temperatures above 24 to 26 °C (75.2 °F to 78.8 °F), labor productivity begins to decline, and at 33 to 34 °C (91.4 to 93.2 °F) , "with moderate work intensity, workers lose 50 percent of their capacity." Dr. Flouris' meta-analysis reinforces this data, where 30 percent of workers under heat stress reported less productivity. "Our bodies seek to protect us," said the physiologist in explaining these findings.

On their routes, delivery drivers are torn between taking a break to protect themselves from exposure to the sun and meeting delivery requests. When they opt for the latter, they not only risk their health due to heat stress, they increase their chances of suffering a serious traffic accident because of dizziness, difficulty concentrating and also because of the strategies they adopt to escape the sun's radiation. "Many times I had to cross on red so as not to stay too long at the traffic light because of the heat, the helmet accumulates a lot of heat," admits Walter Santander, "but at the same time I am taking care of my health because at a traffic light you stay for a minute or 45 seconds and there the heat is very scorching."

The future of work will be with rights or it will not be

Not only radiation, humidity and other environmental factors affect the work of the deliveries. In the interviews workers mention that the heat also comes from the asphalt. Most point to the historic center of Asunción as one of the hottest areas on their routes. Also, main avenues and neighborhoods such as Villamorra. Specialists warned that this would happen in a capital city whose administration sees concrete as a promise of progress. A pioneering study on heat islands says that inequalities in the metropolitan area are not only economic and social, they are also of temperature, and point to the reduction of vegetation and construction among the causes. An investigation by El Surti found that since 2021, the Municipality approved an average of two new fuel stations per month, thanks to the Supreme Court's decision to eliminate restrictions on the installation of gas stations in the name of free competition and to the detriment of the constitutional right to a healthy environment. To date, we count more stations than tree-lined plazas.

What is happening in the capital with the proliferation of gas stations is also being reproduced in other cities in the country, and in a context where the effects of the climate crisis are already being suffered, with more frequent heat waves, it is nothing more than a serious involution. Meanwhile, cities in the region, such as Medellin in Colombia, are taking adaptive actions. There, they replaced the floors and roadways, without reducing vehicle lanes, by planting trees and native plants from the city's Botanical Garden. Thanks to this green corridor, they were able to reduce the temperature by up to 5 degrees Celsius in some areas.

When we asked the municipalities of Paraguay's six major cities what they are doing to adapt to the heat, only Encarnación and Luque responded that they had a reforestation plan to regulate the city's climate, use of materials that prevent heat build-up in buildings, and an early warning system. According to the UN, early warning systems are "a climate change adaptation measure that uses integrated communication systems" so that people and communities can better prepare for climate-related hazards. These systems are most commonly used to warn of storms and hurricanes, but for the UN, they are also needed to warn of heat waves.

The Municipality of Asunción did not respond to the inquiry.

Before traveling to make another delivery, Marcos Maidana adjusts a sleeve to protect himself from the 11 a.m. sun. The busiest hours for delivery drivers are also the hours when solar radiation can affect their health. Image by Elisa Marecos Saldívar. Paraguay.

Delivery workers target those most directly responsible for the situation in which they work to demand protection: employers and authorities. "I work for six companies now. I don't get anything from them … sometimes they have water, but most of them don't offer it. You have to ask them," says Federico Ferreira, 54, president of Sinactram.

In Costa Rica, employers must provide protective equipment, acclimatization time and places with shade and water for outdoor workers. Beatriz González Miers, a 40-year-old delivery worker and also part of the delivery workers' union, dreams of the latter, but in her work space, which is the whole city: "We want a place, for example, in the Plaza de la Democracia, or some other spot downtown where we can sit down for a while, even if it's just to rest our bodies, charge our cell phones, hydrate ourselves and then continue. Like a stop for deliveries."

Delivery drivers in Brazil share the same demand, and so far Brasilia has achieved legislation in this regard, although there are obstacles on the part of the app companies, which are the ones that must pay for the construction of the stops.

The Paraguay office of PedidosYa, a company that operates in 15 Latin American countries and presents itself as a leader in delivery technology, says that although "motorcyclists are external service providers," they are concerned about their wellbeing. Monserrat Carugati, marketing manager, told El Surtidor that a delivery driver can stop to rest and hydrate without harm. "That is to say, if he feels in a situation of extreme heat or cold, it rains, or he feels that his safety is put at risk, the rider can pause his management in the app without time limit, and continue when he feels fit to do so," she assured. They plan to expand the "hydration zones" in the city for active delivery drivers, "where they will be able to take shelter for as long as they feel convenient."

Sarah Schneider, Logistics Manager of Monchis, a Paraguayan delivery company, says that as an active protection measure they have a partnership with a fuel emblem so that delivery drivers can use their stations as a starting and resting point, "in addition to having water, restrooms and outlets for cell phone recharging, among other things.".The company's CEO, Diego Gómez, says they are aware of the impact of heat waves. "This reinforces our determination to implement proactive measures."

Delivery drivers say the heat affects their productivity. According to the ILO, the effect of high temperatures on work will be perhaps the worst economic consequence of the climate crisis. Image by Elisa Marecos Saldívar. Paraguay.

The implementation of safety policies for workers in the face of high temperatures is a pending task of the State, not only because it is already a reality of work in various sectors of the economy such as construction, agriculture, waste collection, gastronomy and delivery. Even if governments together manage to comply with the Paris Agreement and avoid global temperature rise above 1.5 degrees, it is estimated that by 2100 half of the world's population will be exposed to temperatures that the body will not be able to regulate. In another estimate by the Washington Post and Carbon Plant, by 2050, Ciudad del Este will have 29 days a year of highly dangerous heat in the sun; Encarnación, 33 days; Asunción, 52 days; Concepción, 87.

In such a scenario, where high temperatures can profoundly transform our lives, even affecting the economy, adapting labor protection measures is not an option. It becomes indispensable.

Paraguay had a regulation approved in 1992 that prohibits a worker from continuing his activities when his internal temperature exceeds 38 °C (100.4 °F). But when we asked the Ministry of Labor in two requests for information how many audits were carried out to control compliance from 2017 to 2023, they did not answer the query. The regulation, moreover, falls short of the size of the challenge.

Since 2007 in Qatar, where the temperature reaches 45 °C (113 °F) with a relative humidity of 90%, the government has maintained a ban on working outdoors during the hottest hours, which are from 11:30 am to 3 pm. In China, if the temperature reaches 35 °C (95 °F), it is mandatory to reduce the intensity and hours of work. If it reaches 40 °C (104 °F) , the working day is suspended if it is outdoors. And if someone has to work despite these conditions or suffers from heat stroke, he or she must be paid extra.

In Chile there is a decree from the Ministry of Health that establishes limits to work, according to the temperature index of the humid globe, with an equation to calculate the allowed workload according to the type of job and the necessary rest times. The Chilean Safety Association, a non-profit organization associated with the country's industrial sector guilds, disseminates recommendations to avoid heat stress at work, such as, for example, planning heavy work only on days with low temperatures, or avoiding the use of clothes impermeable to sweat vapor if the work space is hot.

Beatriz González Miers has been riding her motorcycle around the city for more than 10 years. She is a member of the Sindicato de Trabajadores en Moto y Afines (SINACTRAM), where they demand rest and hydration stops in different parts of Greater Asunción. Image by Elisa Marecos Saldívar. Paraguay.

Miguel Quintana, a cardiologist and head of the Institute of Cardiovascular Medicine at Sanatorio Migone, believes that the approach to deliveries should be differentiated. "These people are exposed to very high temperatures at peak times. They have to wear helmets, they sweat a lot, they can't hydrate quickly because they have to go from one place to another. In my opinion, I think that in summer, with these high temperatures, the companies have to set other conditions and not use people who buy their own motorcycles to be able to support themselves," suggests the doctor.

But delivery drivers face a double challenge to be protected. So far, employers are not responsible for the most basic labor rights such as employment contracts and social security, and without a single physical workspace, no measurements can be taken to ensure that temperature conditions are safe. The union that brings them together articulates these shortcomings and needs within the framework of a single struggle, which is their right to decent employment. On a planet that is steadily becoming hotter, their desire can be translated as making work humanly possible.


Editorial direction and reporting: Jazmín Acuña

Visual edition: Jazmín Troche and Alejandro Valdez

Reporting: Romina Cáceres, Juliana Quintana, Josué Congo and Maximiliano Manzoni

Coordination with El País: Lorena Arroyo

Visual design and illustrations: William Matsumoto, Naoko Okamoto and Lorena Barrios

Data assistant: Sara Campos

Documentation: Daniela Mohor (Chile) and Joan Royo (Brasil)

Photography: Elisa Marsal and Sandino Flecha



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