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Half of workers start shift dehydrated: productivity and safety suffer

Tips for Working in the Heat

Multiple studies have found that around half of Australian mining workers are starting work dehydrated and that they are likely to remain so for their entire shift, with potentially serious consequences.

A 2013 cross-sectional study of 88 miners from two NSW underground mines found that 58 per cent were dehydrated at the start of their shift.

Furthermore, a 2003 study on 39 workers found that over 60 per cent were dehydrated at the start of their shift, while other studies report similar figures.

These studies also found that some workers attended work with a Urine Specific Gravity (USG) greater than 1.030 which is classified as “clinically dehydrated”.

Given that blue collar workers will sweat an average of four or five litres during a ten hour shift – with losses of eight to 10 litres common – those who attend work already dehydrated are unlikely to recover.

The 2013 study found that workers who commenced their shift dehydrated are 2.6 times more likely to end their shift with poor hydration, compared to those who commenced the shift hydrated.

The 2003 study implemented a target start of shift USG of 1.015, while workers exceeding 1.022 were not allowed into the workplace.

This is because of the safety dangers associated with even mild dehydration – classified as a fluid loss of between 1-4 per cent of body mass. This has significant OHS and productivity implications and impairs work performance and cognitive function, including decision making and visual motor tracking abilities.

Workers not as hydrated as they think:

In the 2013 study, approximately 75 per cent of the 88 workers believed they drank enough fluids – at work and at home – to remain hydrated. Yet of these respondents, the majority were not adequately hydrated and had a mean USG greater than 1.020.

Asked what would increase their fluid consumption at work, 41.8 per cent called for more reliable access to cold palatable water, 20 per cent suggested low calorie flavour additives to increase fluid palatability and 10.9 per cent suggested roster changes to include additional breaks.

Obesity a Dehydration Indicator

The 2013 study also found that miners who were dehydrated during their shift were 42.9 per cent more likely to be obese than their hydrated counterparts. The authors suggested dehydration and obesity were linked issues.

Education Critical:

According to the 2003 study: “Education is vital if a workforce that is exposed to significant levels of thermal stress is to come to work [adequately hydrated], and maintain their hydration state during their work shift.”

The study recommended programmed drinking rather than responding to the thirst sensation and says it is also crucial to replace sodium and other electrolytes lost during sweating.

The 2013 study also says that there is a need for “health promotion interventions” to improve hydration and healthy weight status among miners.

It recommended that home and workplace hydration education strategies be combined with other diet, health and weight loss strategies that promote physical activity and good nutrition.

For more information on managing workplace dehydration, download THORZT’s detailed guides.