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The human body consists mostly of water. As high as 80% of body mass when we are babies, it drops to as low as 60% as we age. The brain, however, remains around 85% water. Of course water does not occur in pure form in the body; it invariably contains dissolved salts, and these salts are instrumental in the body's management of its water resources. The body can remain healthy and fit for work in high temperatures when; these salts are present in sufficient quantity, the body is able to reject heat through sweat, and abundant supplies of drinking water are available. Heat stress is a risk when strenuous work is required, or where water and essential salts are deficient. If the body is prevented from cooling by sweating when protective clothing is worn, its temperature can rise dangerously. High humidity will defeat even the naked body's ability to cool through sweat. Very dry conditions – where sweat never remains on the skin - can conceal the loss of water, increasing the risk of heat stress. This article looks at heat stress and how to protect workers.

Even when all of these factors (hydration, freedom to perspire and so forth) are optimal, there are some conditions in Australia's extreme climates and in some industrial processes that can overwhelm the body's temperature control. It's worth remembering that heat stress will tend to exacerbate certain pre-existing medical conditions.

Symptoms of heat stress include:


Heat and dehydration will impair the brain's ability to function normally. Sufferers from heat stress will become confused, unable to make fast, accurate decisions, and generally lose their mental acuity.

Heat Cramps

shortages of electrolytes will impair muscle function, and can lead to painful cramps.


'heat syncope' results from the dilation of the blood vessels in an overheated body trying to cool itself, leading to inadequate blood flow to the brain.

Heat Exhaustion

characterised by profuse sweating, elevated and irregular pulse, nausea and vomiting and mental confusion. Removing the sufferer to a cool environment, hydrating and resting them should cause these symptoms to abate in 15 minutes or so. If not, medical help should be sought.


characterised by hot, dry skin, of mottled appearance. The body fails to sweat, so its natural cooling ability is lost. The result is an uncontrollable rise in body core temperature, convulsions and loss of consciousness, and possibly death. Immediate medical assistance is necessary.

What you can do


ensure that the workforce is properly hydrated. It is legally required to provide adequate drinking water to workers. Workers should also receive some education about hydration management, allowing them to take responsibility for water consumption. In certain conditions, a worker may already be significantly dehydrated before they are thirsty. Routine hydration should be encouraged to alleviate risk of dehydration. Darkening of the urine is a useful indicator that dehydration has occurred, and should be addressed immediately. Caffeine, drink sweeteners and alcohol impair the body's water management processes, and workers should be aware of this.

Electrolyte replenishment

however well hydrated a body is, it must also maintain adequate resources of salts as to not damage the nervous system. SafetyQuip stocks Thorzt electrolyte replenishment products that rehydrate and assist in sustained energy release.


where this is available, make sure it is providing optimum air exchange for the conditions.

Protective Wear

resourceful apparel is available to protect workers from various workplace hazards. If extended work in extreme heat is unavoidable, and protective workwear is necessary to guard against other hazards, evaporative or ice suits should be supplied. Evaporative suits work when immersed in water, soaking the lining. They provide cooling for as long as they are wet. Ice suits, otherwise known as Phase Change Cooling Apparel, use flexible ice blanket inserts to provide powerful cooling for up to 3 hours.

Workplace design

manage the location of heat-inducing activities by using heat shields and reflective apparel. If possible, schedule hot processes for cool parts of the day. Have cool areas available for recovery.

Workforce Scheduling

plan your manpower schedules so that individuals are not assigned to lengthy periods in stressful conditions. Where appropriate, assign more manpower to tasks involving extreme exertion in hot conditions. Take care to monitor each worker's exposure to stress, and to ensure that safe limits are not exceeded by overtime.

SafetyQuip can supply you with all the equipment and supplies you need to counter heat stress in your workforce. To learn more about heat stress, and for specialist advice on the equipment your workplace needs, send ua a contact request here