Study identifies effective mitigation strategies to keep workers safe from heat stress

Largest ever study on the impact of heat stress reveals effectiveness of a number of existing approaches, and makes recommendations to better protect workers during summer months

Press release | 11 October 2019

DOHA (ILO News) – Outdoor workers in Qatar are able to perform their roles safely, despite the summer heat and humidity, if effective precautionary measures are in place. This is the key finding from a study commissioned by the International Labour Organization (ILO) and the Ministry of Administrative Development, Labour and Social Affairs, in collaboration with the Supreme Committee for Delivery & Legacy (SC).

Throughout the summer, the FAME Lab from the University of Thessaly, a leading institution in this field, collected data on workers’ physiology and labour effort, covering more than 5,500 work hours. This is the largest ever study of its kind and the first in the region. The research examined a construction site with 4,000 workers (a World Cup stadium) with a comprehensive heat stress management plan, and a farm with fewer precautions in place. The research examined different strategies for mitigating heat strain, focusing on hydration, work-rest ratios and clothing.

The research found the amount of time that workers’ core body temperature exceeded the safety threshold of 38 °C (proposed by the World Health Organization) was low. On the construction site, this averaged zero to three per cent of the workers’ shift and on the farm eight per cent.

“One of the key reasons why workers on the World Cup site were at low risk to occupational heat strain, was because they were empowered to self-pace and take breaks,” said Dr. Andreas Flouris, head of the FAME Laboratory. “This was a key element of the heat mitigation plan, and was how workers were able to cope with the heat and humidity.”

Workers’ labour effort was recorded on a second-by-second basis, and the labour intensity was low. On the World Cup site, workers were on breaks for 62 per cent of their work shift, and 32 per cent of their work was carried out at low intensity (0.1 to 1.4 W / m2). The farm workers were on breaks for 23 per cent of their shift, and carried out 67 per cent of their shift at low intensity.

The study found that many workers were dehydrated at the start of their shifts, underscoring the importance of effective hydration strategies. The research also tested different clothing options, including the dark-coloured overalls that are typically worn by construction workers, against white overalls, a cooling suit developed by the SC, and a cooling vest with embedded solar-powered fans. The study found that the SC suit and the white overalls can effectively reduce the heat strain experienced by workers.

Recommendations made by the study include adjusting the summertime working hours, mandatory heat stress mitigation plans for all companies across Qatar, annual health checkups for workers, as well as greater worker empowerment. There are also specific recommendations on clothing, access to drinking water and working in shaded areas.

“We are working with the Government to translate the recommendations of this study into improved legislation, and to promote the replication of the good practices that were identified,” said Houtan Homayounpour, Head of the ILO Project Office in Doha. “We have a scientific basis on which to propose adjustments to the prohibited working hours during summer, and it is clear that heat stress mitigation plans must recognize the right and enhance the ability of workers to self-pace.”

At the beginning of summer 2019, the Labour Inspection Department disseminated heat stress guidance for employers and workers, which had substantial reach on social media. Labour inspectors also shut down 310 work sites for violating the regulation on prohibited working hours between 15 June and 31 August.

The FAME Lab is part of the University of Thessaly’s School of Exercise Science. Dr Andreas Flouris is the head of the Lab. He has been a member of Working Groups providing input for guidelines and policy pertaining to the health effects of different environmental factors for many international organizations (World Health Organisation, United Nations, European Commission, NASA, and others). He is an author of the global recommendations for work in hot environments to be jointly published in 2020 by the World Health Organization and the World Meteorological Association.

For more information, please contact Steve Needham, Communications Officer, ILO Project Office for the State of Qatar at Mob +97450069011 or at