Hydration status and physiological workload of UAE construction workers: a prospective longitudinal observational study

Graham P Bates,John Schneider

doi:10.1186/1745-6673-3-21

Graham P Bates, John Schneider

Open Access

https://doi.org/10.1186/1745-6673-3-21

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Abstract

BackgroundThe objective of the study was to investigate the physiological responses of construction workers labouring in thermally stressful environments in the UAE using Thermal Work Limit (TWL) as a method of environmental risk assessment.MethodsThe study was undertaken in May 2006. Aural temperature, fluid intake, and urine specific gravity were recorded and continuous heart rate monitoring was used to assess fatigue. Subjects were monitored over 3 consecutive shifts. TWL and WBGT were used to assess the thermal stress.ResultsMost subjects commenced work euhydrated and maintained this status over a 12-hour shift. The average fluid intake was 5.44 L. There were no changes in core temperature or average heart rate between day 1 and day 3, nor between shift start and finish, despite substantial changes in thermal stress. The results obtained indicated that the workers were not physiologically challenged despite fluctuating harsh environmental conditions. Core body temperatures were not elevated suggesting satisfactory thermoregulation.ConclusionThe data demonstrate that people can work, without adverse physiological effects, in hot conditions if they are provided with the appropriate fluids and are allowed to self-pace. The findings suggested that workers will self-pace according to the conditions. The data also demonstrated that the use of WBGT (a widely used risk assessment tool) as a thermal index is inappropriate for use in Gulf conditions, however TWL was found to be a valuable tool in assessing thermal stress.

Highlights

The objective of the study was to investigate the physiological responses of construction workers labouring in thermally stressful environments in the UAE using Thermal Work Limit (TWL) as a method of environmental risk assessment
Maintaining a stable core body temperature in the face of changing environmental conditions and metabolic workloads allows humans to function in diverse climates and surroundings
All participants were volunteers who gave their written and informed consent to participate in the study, which was authorised by management and approved by the AlAin Medical District Human Research Ethics Committee

Summary

Introduction

The objective of the study was to investigate the physiological responses of construction workers labouring in thermally stressful environments in the UAE using Thermal Work Limit (TWL) as a method of environmental risk assessment. The United Arab Emirates and other Gulf States have thousands of expatriate workers performing physical tasks in very hostile environmental conditions during summer. To date there have been few studies to document the hydration status and possible fatigue of these workers whilst working in the heat. In addition the hydration status of these workers has not been documented. Thermoregulation depends upon the dissipation of body heat to the environment. Sweating cools the skin by evaporation and is the principal heat loss mechanism when working in very hot environments. Increased blood flow to the periphery of the body can cause significant heat loss through convective currents and radiation

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