It is dangerous for people to work in extreme heat. To function properly, the human body must sustain a consistent body temperature of roughly 37 degrees Celsius. When the body overheats and exceeds this internal body temperature, it results in heat-related illness, also known as hyperthermia. There is a wide range of heat-related conditions that vary in degrees of severity, from minor conditions to life-threatening ones. They include heat rash, heat syncope (fainting), heat exhaustion, heat cramps, and heat stroke.

Read on to learn the signs and symptoms of heat-related illness, and what employers can do to protect their workers.

Heat in the Workplace

Heat in the workplace goes beyond the thermostat temperature. There are a number of factors that go into the heat workers are exposed to and all of them should be monitored and managed within the workplace.

Safe Work Australia says workplaces should consider:

  • air temperature
  • air flow
  • humidity
  • radiant heat sources
  • work requirements, and
  • the workplace itself

Read Safe Work Australia’s health and safety guide to heat. It contains practical guidance for any business to manage the risks of working in heat as well as more information about what to do if a worker begins to suffer from a heat-related illness.

Negative Effects of Working in Heat

Reduced Concentration

A worker’s ability to concentrate is significantly impeded by working in hot conditions. Without the ability to concentrate, workers can easily become confused and are more prone to making mistakes. A worker could forget to turn off a piece of machinery or make a potentially life-threatening mistake if they are operating a motor vehicle. Industries that use vehicles or dangerous machinery should be especially wary of excessive heat for workers because there is no room for error.

Heat Exhaustion and Heat Stroke

Heat exhaustion can occur after prolonged activity in a hot environment, which can overwhelm the body’s ability to cool down. Signs include profuse sweating, lightheadedness, headache, nausea and vomiting, and muscle cramps. A worker with these symptoms should be immediately removed from this environment to a cooler area, be given water, and have a cool or wet towel placed on their neck and forehead.

If these symptoms are ignored or not addressed, heat exhaustion can lead to heat stroke, which can be fatal. If a worker is no longer sweating and appears confused or disoriented, there is a good chance they are suffering from heat stroke. If any of these symptoms occur, the worker should be immediately taken to a cool environment as quickly as possible. Have the worker lie down and rub their skin with cool water to encourage the body to begin to sweat. It’s important to cool the person down as quickly as possible.

Emergency medical services must be notified as soon as possible, as the worker’s life is in serious danger. Heat stroke, if left untreated, can cause heart, kidney, muscle, and brain damage. In extreme circumstances, the worker may also fall into a coma. The longer the delay, the worse the complications may be. Elderly workers are particularly at risk of heat exhaustion and heat stroke.

Heat Rash

A heat rash occurs when a person’s sweat glands are blocked, and sweat cannot evaporate off the skin, resulting in itchy, irritated skin, red bumps, or blisters. These symptoms can be alleviated by placing something cool on the affected areas.

Heat Syncope (Fainting)

Fainting is extremely dangerous to workers, as a person who has fainted has no control over where they land or what they land on. Fainting is caused by excess heat and dehydration. When your body is struggling to cool itself, it can dilate the body’s blood vessels to such a degree that blood flow to the brain becomes reduced. When blood flow to the brain is impeded, it results in dizziness, nausea, and, in extreme cases, loss of consciousness.

Heat Cramps

Heat cramps are involuntary, sporadic muscle spasms, usually of the major muscle groups being used in the hot work environment. They occur after a worker has been sweating profusely without replenishing their body with adequate salt and electrolytes, resulting in severe dehydration.


Profuse, consistent sweating can lead to dehydration. The human body needs water to function, as up to 60% of the human body is water. When more water is being expelled than taken in, the body becomes dehydrated and cannot function as intended. Signs of dehydration are thirst, infrequent urination and darkening of the urine, as well as dry mouth, lightheadedness, and muscle cramps.

Burns from Hot Surfaces

If a worker comes in contact with a hot tool or surface, they can burn their skin. These burns can be very serious, so great care must be taken while working with heated tools or hot surfaces.

Increased Risk of Slips

Sweating in hot conditions can increase the risk of slips. If a worker’s hands are damp and slick with sweat, they could lose grip on their tools. If the tool is sharp or dangerous, a serious accident could occur.

Chemical Absorption

Heat can cause the body to absorb chemicals more quickly and more significantly. If a worker is on medication, its side effects can increase.

How Employers Can Manage Heat in the Workplace

Monitor and Regulate Workplace Heat

Ensure your workplace remains at a stable temperature. If you haven’t already, invest in air con, so you and your employees can regulate their own environment, and make sure the area is well-ventilated. Keep your workplace cool on hot days.

If you employ outdoor workers, ensure they take breaks in a cool environment regularly. Heat-related conditions occur faster than you think, so take care to monitor the temperature of your work environment consistently to keep it agreeable at all times. Consider the temperature, radiant heat sources, air flow, and humidity when assessing heat in your workplace, whether that’s indoors or outdoors.

Ensure Workers Do Not Work Alone

When working around heat, ensure your employees are not working alone. If a worker is suffering from heat exhaustion, they will be disoriented, and may not be able to recognize the signs themselves. They could faint, and if left undiscovered for an extended period of time, they could die.

If an employee must work alone, ensure they are monitored consistently, and make sure that there is always someone within earshot so the employee can easily call for help.

Schedule Regular Breaks

All employees need breaks. Those who work outside or in warm conditions need breaks more often in order to hydrate, apply sunscreen, and rest. Ensure all workers take their scheduled breaks, and that no one tries to tough it out to continue work. Spread breaks out throughout the day and add more for hotter conditions or days of extreme heat.

Schedule Strenuous Work on Cooler Days

Save heavy or strenuous work for cooler days. If there’s a risk of extreme heat, hold off on physically demanding work if possible. If physical work is required, ensure there is an increase of breaks during the hottest times of the day. Schedule the most strenuous work in the morning and evening when temperatures are cooler. At these times, there will be less risk of sun exposure as well.

Provide Water

Always ensure water is readily available in the workplace. The amount of water the body needs varies depending on sex, age, and weight, but generally, men and women need 2-3 litres of water a day. Not only will drinking plenty of water help manage heat, but water also improves a person’s cognitive function. Hydrated employees are better able to concentrate, are more focused, and they feel better.

Provide Shade For Outdoor Workers

Shade is vital to the health of outdoor workers. Ensure all break areas have adequate shade from the sun. If your break areas do not have shade, create them with umbrellas or tents.

Not only will extended time underneath the beating sun cause heat-related illness, but prolonged exposure to UV rays from the sun causes skin cancer.

💡 Learn more about skin cancer awareness, how to prevent skin cancer, and what employers can do to help: The Risks of Skin Cancer and How to Keep Your Skin Safe.

Educational Resources on Heat-Related Risks

Provide your employees with educational resources on the risks of overheating and hyperthermia. Without education, a worker may ignore or be ignorant of the signs of heat-related illness. They may delay hydrating in order to accomplish a task or try to relieve a headache with a pill rather than a glass of water, which would only aggravate their condition.

Educate your workers on the dangers and signs of overheating to reduce employee injury and illness.

Workforce Health Assessors offers comprehensive pre-employment, pre-placement, and periodic medical assessments tailored to the needs of your business. We organise, perform, and report on all health assessments and medicals to help you determine the suitability of candidates for your business and mitigate risks in the workplace. Our tests are carefully designed and vary depending on the specifications of the role a candidate will fill. Learn more about our health assessment services.

Continue Supporting Your Workforce

The construction industry has the third-highest number of worker fatalities in Australia. Learn more about Pre-Employment Medicals for the Building and Construction Industry.

In an industry as high-risk as mining, pre-employment medicals and ongoing medical assessments can prevent injuries and fatalities. Learn more about Pre-Employment Medicals for the Mining Industry.

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