Hydration in heat: how does your workplace measure up?

Summer is fast approaching, and while many of us can escape Australia’s rising temperatures in air-conditioned vehicles and offices, there is a susceptible portion of the workforce whose health is at risk from dehydration in hot environments.

Working in heat is a reality for many industries that operate under direct sunlight like construction or farming, or for workers who are exposed to radiant heat from hot machinery, often indoors, like boiler makers or factory workers. According to the State of the Climate 2014 report, Australian temperatures are projected to continue to increase with more extremely hot days and fewer extremely cool days.^[1] 2014 saw the warmest year on record for NSW and Victoria with particularly high temperatures in January (some places reaching close to 50°C).^[2] With increasingly warm days ahead, it is essential businesses have heat management strategies and appropriate equipment and supplies available to ensure the health and safety of their workers.

The importance of hydration

When the body is exposed to more heat than it can cope with, it can lead to heat stress and dehydration. Air temperature, humidity, clothing, the intensity of physical activity and the duration are all contributing factors. Working in intense heat can raise normal body temperature and in a worst-case scenario lead to heat stroke and possible death. Heat stress and dehydration may also impair thinking and reaction times, which can put workers at risk of injury by being susceptible to making errors, dropping tools or stumbling.

Signs a person is affected can range from muscle cramps, light-headedness to speech confusion or fainting. Those at greater risk include people who are overweight or physically unfit, not acclimatised to working in heat and are over 65. Workers who suffer from heart disease, take certain medications or have alcohol in their system, are also at a higher risk.

Maintaining adequate hydration is one of the most important strategies to counteract the effects of heat stress.^[3] Speaking on the topic of hydration at a safety seminar at the Safety in Action conference in Melbourne last month, Sharon Groombridge, national training manager for Care Pharmaceuticals, said workers will experience increased sweating as the body attempts to cool itself and can lose as much as 1 L of sweat per hour. Since fluid and electrolytes (which help retain fluid) are lost in sweat, this can lead to dehydration.

“Oral hydration is hailed as the most important medical advance of the twentieth century,” said Groombridge. “The fastest way to clinically rehydrate is through an oral hydration solution such as Hydralyte, which has one quarter of the glucose levels and four times the electrolytes of sports drinks.”

Hydralyte, which is also safe for diabetics, can be consumed in ice blocks, ready-made drinks, and effervescent electrolyte tablets or powder sachets that dissolve in water. Groombridge said there has been a lot of negative noise around sugary drinks, and if workers are getting their energy requirements through their food, they don’t need it in their drinks as well. Since sugary drinks like juice or soft drink do not restore lost electrolytes, they are less effective at rehydration and provide unnecessary kilojoules.

Dehydration not just a risk in hot climates

A 2013 study of underground miners* in temperate regions has shown that it’s not just workers in typically hot and tropical regions who are at risk of dehydration while at work.^[4] The study looked at two mines in south-eastern NSW with an average mean temperature of 23.1°C and found that dehydration in miners and being overweight were linked issues.

Hydration was measured by testing urine and results showed that 58% of miners arrived to work already dehydrated, with several workers showing signs of clinical dehydration both pre- and post-shift. The study stated that the consumption of water during a shift was unlikely to rehydrate an already dehydrated worker due to the influence of metabolic work load and sweat rates while working. It was also found that the miners with urine results indicating dehydration were more likely to be obese (42.9%) than workers who were adequately hydrated for their shift.

The risk of medical conditions like exercise asthma, fatal coronary heart disease, stroke or chronic renal disease have been shown to be reduced with good hydration. While workers in the study had access to water both above and below ground, it was also suggested that improved access to palatable drinking water and the removal of energy-dense, nutrient-poor drinks in vending machines (since shift workers can consume up to three servings of soft drink in a single shift) could assist in promoting water consumption and maintaining hydration — as well as aiding in improved food and drink choices. Neither mine had guidelines for hydration; however, for companies concerned about the long-term health and wellbeing of their employees, the issue of dehydration may need to be considered in their health and safety policies, along with the provision of low-sugar products to combat it.

Top tips for staying hydrated

According to WorkCover Queensland, workers won’t feel thirsty until they have lost 1–2% of their body weight in fluid and should drink to keep pace with sweat losses (recommendations are to drink regularly between 600 mL and 1 L of water per hour). This is particularly important for ageing workers as the sensation of thirst decreases as you get older, increasing the risk of dehydration.^[5] Care Pharmaceuticals says the aim is not to wait until you are dehydrated and treat it, but to minimise the chance of becoming dehydrated in the first place. Their top tips to avoid workplace dehydration include:

1. Starting the day hydrated: Workers should aim to have their urine clear to straw colour before starting work, and for particularly hot days or jobs that require excessive exercise, this may mean hydrating the night before.
2. Recognising the signs of dehydration: Dry mouth, headaches, thirst, fatigue, dizziness, lack of concentration or decreased or dark urine.
3. Allowing access to water and electrolytes: Where possible, ensure workers have access to cool drinking water and an oral rehydration solution such as Hydralyte, when necessary.
4. Avoiding work in direct sunlight: Where possible, arrange outdoor work early in the morning or late in the afternoon.
5. Being sun smart: Wear light-coloured, loose clothing to permit good airflow, broad-brimmed hats, sunglasses with UV and glare protection ratings etc as sunburn stops your body from cooling itself down properly.

*88 participants were voluntarily recruited; all participants were male, aged 18 years and older. Participants conducted diverse tasks in the mine with the majority requiring strenuous physical exertion.

References

[1] Commonwealth of Australia 2015, Bureau of Meteorology and CSIRO, 2014, State of Climate 2014 report, viewed 24 September 2015, <www.bom.gov.au/state-of-the-climate/documents/state-of-the-climate-2014_low-res.pdf?ref=button>.

[2] Commonwealth of Australia 2015, Bureau of Meteorology, 'New South Wales in 2014: the warmest year on record', viewed 24 September 2015, <www.bom.gov.au/climate/current/annual/nsw/summary.shtml>; and 'Victoria in 2014: Another very warm year with very dry conditions in the west', viewed 24 September 2015, <www.bom.gov.au/climate/current/annual/vic/summary.shtml>.

[3] State of Queensland (WorkCover Queensland), 15 September 2015, 'Heat Stress', viewed 24 September 2015, <www.worksafe.qld.gov.au/injury-prevention-safety/workplace-hazards/dangers-in-your-workplace/heat-stress>.

[4] Polkinghorne et al, 2013, Hydration status of underground miners in a temperate Australian region, BMC Public Health 2013, viewed 24 September 2015, <www.biomedcentral.com/1471-2458/13/426​>. 

[5] European Hydration Institute, 2013, 'Thirst', viewed 24 September 2015, <www.europeanhydrationinstitute.org/human-hydration/thirst/>.

Image credit: ©iStockphoto.com/Pamela Moore