Heat stress monitoring based on heart rate measurements.

Currently, occupational heat exposure is usually measured using environmental variables such as the wet bulb globe temperature index. The costs of heat stress monitoring include the acquisition of specialized equipment and the recruitment of trained personnel. In rapidly changing environments, such as outdoor settings, these assessments must be conducted on a daily basis. The wet bulb globe temperature index has been criticized as a measure of heat stress for its failure to account for individual differences in susceptibility to heat stress, age, body mass index, physical fitness, clothing, illnesses and use of alcohol or drugs. The objective of this study was to assess the relationship between heart rate and body temperature in heat-exposed workers to determine whether heart rate can be used to monitor and prevent heat stress and physiological strain. This study was based on previous literature as well as physiological and environmental data collected from 10 individuals engaged in heavy physical labor. Heart rate, which has been recommended by the American Conference of Governmental Industrial Hygienists (ACGIH) as a possible measure of heat stress, follows a similar trend to body temperature with a slight temporal delay. Heart rate monitors with alarm systems could be developed to notify workers when to slow down their activities or take a break for thermal recovery, thereby contributing to the prevention of heat-related illness.

[Risk of exposure to heatstroke in sugarcane workers in São Paulo State, Brazil]. / Risco de exposição à sobrecarga térmica para trabalhadores da cultura de cana-de-açúcar no Estado de São Paulo, Brasil.

Environmental heat is an aggravating factor for sugarcane workers, and manual cane cutting is one of the heavy work activities that favor the generation of metabolic heat. This can combine with other precarious working conditions to produce heatstroke, potentially leading to serious complications and even death. The study aimed to quantify the risk of overheating in sugarcane cutters in São Paulo, Brazil. Drawing on a specific methodology, the study used four years of data to estimate the Globe Thermometer Wet Bulb Index based on light, moderate, and heavy activities. The results showed that the legal limit was exceeded for continuous activity in periods from 1 to 8 hours, which requires control measures in order to continue working. The principal observation was the risk of heatstroke in the three types of activity: light, moderate, and heavy. The limits were exceeded throughout the work shift on 7% of the days for heavy activity and on 3% of the days for moderate activity. In addition, the areas with the highest risk of heatstroke coincide with predominant cane-growing.

Risco de exposição à sobrecarga térmica para trabalhadores da cultura de cana-de-açúcar no Estado de São Paulo, Brasil / Risk of exposure to heatstroke in sugarcane workers in São Paulo State, Brazil / Riesgo de exposición a la sobrecarga térmica para trabajadores de plantaciones de caña de azúcar en el estado de São Paulo, Brasil

Resumo: O calor ambiental é um agravante às atividades dos trabalhadores da cultura de cana-de-açúcar, sendo o corte manual uma das atividades pesadas que favorece a elevada geração de calor metabólico. Isso associado com outras condições precárias de trabalho favorece o estresse térmico, podendo provocar graves doenças ou até levar à morte. O objetivo deste estudo é quantificar o risco de sobrecarga térmica que os cortadores de cana-de-açúcar de São Paulo, Brasil, são expostos. Por meio de metodologia específica, foram utilizados quatro anos de dados para estimar o Índice de Bulbo Úmido - Termômetro de Globo sob a consideração das atividades leve, moderada e pesada. Os resultados mostram extrapolação do limite legal de exposição para atividade contínua em períodos de 1 a 8 horas, o que requer medidas de controle para continuidade do trabalho. A principal constatação é a observância do risco de sobrecarga térmica para os três tipos de atividade: leve, moderada e pesada. Os limites de tolerância são ultrapassados durante todo o turno de trabalho em cerca de 7% dos dias, para atividade pesada, e em cerca de 3%, para atividade moderada. Além disso, percebeu-se que as áreas com maior risco de sobrecarga térmica são as mesmas onde há predominância da cultura de cana-de-açúcar.

Abstract: Environmental heat is an aggravating factor for sugarcane workers, and manual cane cutting is one of the heavy work activities that favor the generation of metabolic heat. This can combine with other precarious working conditions to produce heatstroke, potentially leading to serious complications and even death. The study aimed to quantify the risk of overheating in sugarcane cutters in São Paulo, Brazil. Drawing on a specific methodology, the study used four years of data to estimate the Globe Thermometer Wet Bulb Index based on light, moderate, and heavy activities. The results showed that the legal limit was exceeded for continuous activity in periods from 1 to 8 hours, which requires control measures in order to continue working. The principal observation was the risk of heatstroke in the three types of activity: light, moderate, and heavy. The limits were exceeded throughout the work shift on 7% of the days for heavy activity and on 3% of the days for moderate activity. In addition, the areas with the highest risk of heatstroke coincide with predominant cane-growing.

Resumen: El calor ambiental es un agravante para las actividades de los trabajadores de plantaciones de caña de azúcar, siendo el corte manual una de las actividades pesadas que favorece la elevada generación de calor metabólico. Esto, asociado con otras condiciones precarias de trabajo, favorece el estrés térmico, pudiendo provocar graves enfermedades o incluso llevar a la muerte. El objetivo de este estudio es cuantificar el riesgo de sobrecarga térmica a la que los cortadores de caña de azúcar de São Paulo, Brasil, están expuestos. Mediante una metodología específica, se utilizaron cuatro años de datos para estimar el Índice de Bulbo Húmedo-Termómetro de Globo, considerando a las actividades como: leves, moderadas y pesadas. Los resultados muestran la extrapolación del límite legal de exposición para la actividad continua en períodos de 1 a 8 horas, lo que requiere medidas de control para la continuidad del trabajo. La principal constatación es la observancia del riesgo de sobrecarga térmica para los tres tipos de actividad: leve, moderada y pesada. Los límites de tolerancia se sobrepasan durante todo el turno de trabajo en cerca de un 7% dos días, en el caso de la actividad pesada, y en cerca de un 3% en la actividad moderada. Además, se percibió que las áreas con mayor riesgo de sobrecarga térmica son las mismas donde hay predominancia de plantaciones de caña de azúcar.

[Analysis of the contribution of meteorological variables to thermal stress associated with death among sugarcane cutters]. / Análise da contribuição das variáveis meteorológicas no estresse térmico associada à morte de cortadores de cana-de-açúcar.

Sugarcane cutters perform heavy work under adverse conditions. Environmental factors can be an aggravating factor for thermal stress among these workers. This study analyzed the atmospheric conditions on the day of death of 14 sugarcane cutters in São Paulo State, Brazil. Historical data for temperature, humidity, wind, and sunlight were compared with the same meteorological variables on the days the deaths that occurred. The meteorological data were obtained from a reanalysis of the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR). In 10 of the 14 cases, the temperature on the day of death was higher than or equal to the mean plus the standard deviation. In six of these cases, the temperature reached or came close to record levels. These findings suggest that atmospheric conditions can be an important factor in the analysis of overall work conditions for sugarcane cutters.

Análise da contribuição das variáveis meteorológicas no estresse térmico associada à morte de cortadores de cana-de-açúcar / Analysis of the contribution of meteorological variables to thermal stress associated with death among sugarcane cutters

Os cortadores de cana-de-açúcar exercem atividade muito pesada e em condições precárias de trabalho. Além disso, fatores ambientais podem ser um importante agravante à sobrecarga térmica desses trabalhadores. Neste artigo, analisa-se a condição atmosférica no dia da morte de 14 trabalhadores do corte de cana-de-açúcar no Estado de São Paulo, Brasil. Compara-se valores estatísticos históricos da temperatura, umidade, vento e radiação com os valores destas variáveis meteorológicas observadas no dia de cada óbito. Os dados atmosféricos foram obtidos da reanálise do National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR). Em 10 dos 14 casos analisados, as temperaturas observadas nos dias dos óbitos foram maiores ou iguais à média somada ao desvio-padrão. Em seis desses casos o valor da temperatura atingiu ou ficou muito próxima do recorde histórico. Constatou-se que a condição atmosférica pode ser um fator importante a ser considerado na análise das condições gerais de trabalho dos cortadores de cana-de-açúcar.

Sugarcane cutters perform heavy work under adverse conditions. Environmental factors can be an aggravating factor for thermal stress among these workers. This study analyzed the atmospheric conditions on the day of death of 14 sugarcane cutters in São Paulo State, Brazil. Historical data for temperature, humidity, wind, and sunlight were compared with the same meteorological variables on the days the deaths that occurred. The meteorological data were obtained from a reanalysis of the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR). In 10 of the 14 cases, the temperature on the day of death was higher than or equal to the mean plus the standard deviation. In six of these cases, the temperature reached or came close to record levels. These findings suggest that atmospheric conditions can be an important factor in the analysis of overall work conditions for sugarcane cutters.