A quick guide to managing the risks of heat stress at work

Our brutally hot Australian summers are renowned for turning work that can usually be performed comfortably, into a hazardous experience that can cause heat illnesses with serious impacts on employee’s health, safety and productivity. Whether work happens outside or inside with machinery, the guide below outlines what employers can do to reduce the risks of heat exposure during our hottest months.

What are the risks of heat stress?

Aside from being uncomfortable, being exposed to high temperatures poses a risk of heat illnesses, poor employee health, potential accidents, and time off work for recovery.

Exposure to sun and/or heat in the workplace, combined with the mental and physical demands of work, can worsen existing medical conditions like kidney, heart or lung diseases. Additionally, heat stress, and it’s associated illness’, also bring on, or exacerbate, signs of workplace fatigue such as:

• Tiredness
• Irritability
• Blurred vision
• Inability to concentrate
• Memory lapse
• Underestimation of risk
• Slower reactions/coordination
• Decreased awareness
• Lack of attention
• Poor execution
• Distractibility

Fatigue increases the risk of accidents and errors in a similar way to drugs and alcohol, placing workers, customers/clients, property, and in some cases, members of the public, in danger of injury. It’s vital then that both workers and employees take steps to reduce exposure to the sun and heat and minimise the effects of heat.

Understanding heat illnesses

What are they?

The ideal body temperature is 37 degrees, however when our core body temperature is raised by only a few degrees, our organs and systems are exposed to heat stress which causes cell death.​ A body temperature above 40 degrees can cause disorientation, with convulsions and permanent cell damage possible above 42 degrees.

Exposure to high external temperatures in the workplace – particularly when performing physically rigorous tasks – can increase our core body temperature causing disturbances to metabolic processes and heat illness. In general, heat-related illnesses can be identified by*:

• Muscle or abdominal cramping
• Fatigue
• Rapid heart rate
• Dark coloured urine (sign of dehydration)
• Headache
• Dizziness​
• Confusion
• Nausea

(*These can also be symptoms of cardiac arrest, so if you experience chest pain, shortness of breath or palpitations as well, call an ambulance). 

Who is at risk?

Any employee who works outside in the sun or performs rigorous physical duties can suffer from heat-related illnesses. However, there are certain modifiable factors that place individuals at a higher risk:

• High alcohol and caffeine intake
• Skipping breakfast​
• Low fitness levels​
• Poor rehydration during and after exercise sessions​
• Body composition – adipose (fat) tissue is an excellent insulator ​and retainer of heat
• Body size – surface: volume ratio​
  • Heat loss must occur across a body surface​
  • Small individuals lose heat more readily than large individuals

The risk of heat related illnesses also increases for people:

• on certain medications including diuretics (fluid tablets), beta-blockers, drugs with anticholinergic properties, and central nervous system stimulants.
• with certain pre-existing medical conditions such as cardiovascular disease, kidney disease, mental illnesses, lung conditions or diabetes.

How to identify and treat heat illnesses

Below is a list of common heat illnesses in order of severity and how you can treat them.

• Dehydration:
  • Symptoms: headache, thirst, decreased urine volume, dark urine.
  • Treatment: give cool water to drink and move to a cool location.
• Heat rash:
  • Symptoms: a raised, itchy rash where sweat collects and blocks sweat ducts. It can cause redness, prickling and mild swelling.
  • Treatment: move to air-conditioning, keep the skin dry, take a cool bath or shower and wear loose, cotton clothing.
• Heat cramps​:
  • Symptoms: painful cramping of muscles, most likely caused by to mineral losses and dehydration.
  • Treatment: move to a cooler location, give cool fluids like water or an electrolyte replacement drink. Seek medical attention if symptoms persist beyond one hour.
• Heat exhaustion
  • Symptoms: ​extreme fatigue, vomiting, breathlessness, dizziness​, skin may be cold and clammy​. Employees could be more susceptible if they aren’t fit or are unacclimatised to a new job or working environment.
  • Treatment: move to a cooler location, give cool fluids like water or an electrolyte replacement drink. Seek medical attention if symptoms persist beyond one hour.
• Heat stroke (life threatening)​
  • Symptoms: the cessation of sweating (critical warning sign) ​, hot, dry skin​, rapid pulse and respiration that is rapid and shallow​, high blood pressure and throbbing headache​, confusion, unconsciousness​.
  • Treatment: Seek medical assistance immediately​! Do not give fluids. Remove items of clothing and place person on their side to expose as much surface area for cooling, move to a cool location, sponge or spray with cool water and fan the person, apply ice packs to groin, neck and arm pits​.

Reducing the risks of heat stress

Both workers and employers have a responsibility to take actions that reduce the risks of heat exposure and therefore the likelihood of heat related illnesses and fatigue. Fortunately, these actions are simple.

Individuals can:

• Avoid or limit exposure to high temperatures and high humid environments at work
• Take frequent breaks at work in cool areas or indoors
• Carry a water bottle or water bladder and sip water throughout their shifts
• Apply sunscreen and protective clothing
• Look out for their colleagues for signs of heat illness
• Monitor the colour of their urine – a dark colour is a sign to drink more
• Eat small, light meals of cold food – starch-heavy meals with fried or processed foods require more digestion which creates heat
• Reduce alcohol and caffeine intake – both are diuretics which lead to dehydration

Supervisors can:

• Implement engineering and work practice controls i.e. increase air velocity (fans), reflective or heat absorbing shields
• Increase the number of workers per task
• Provide a cool area for breaks if possible
• Monitor and encourage adequate fluid intake and rest breaks
• Implement appropriate acclimatisation for new employees
• Adjust the work schedule if possible and assign heavier work on cooler days or during the cooler part of the day
• Provide sunscreen, protective clothing, sunglasses
• Provide plenty of access to drinking water
• Provide education to workers about heat stress and hydration

A word about hydration

A change in body water content can have fatal consequences​.

The human body is around 72% water, but loss as small as 2% body water can significantly affect our physical and cognitive functions, increasing our risk of injury or accident.

Dehydration occurs when we have less water than water our body needs to function correctly and triggers an attempt to conserve water. Unfortunately, this slows down the body’s processes causing feelings of sleepiness, problems with blood pressure, heart rate and body temperature. In extreme cases, it can cause weakness or confusion, kidney damage or even brain damage.

Thirst however is not always good indicator of hydration – by the time we feel thirsty we may have already lost 1 to 2% body water​ – so “programmed drinking” is essential. As a rule of thumb, when working in the heat we should drink 1 cup of water every 15 – 20 minutes. We recommend the following water consumption levels for different roles:

Field workers (non-manual)​: 600mL/hr of water (plus food and other beverages)​.

Manual workers​: 1L/hr of plain water (accompanied by frequent meal breaks) or an industrial rehydration fluid. During prolonged sweating lasting several hours, sports drinks containing balanced electrolytes help to replenish salts lost in sweat.​

​Sedentary workers: 400mL/hr water (plus food and other beverages).

While it’s tempting, it’s important to avoid energy drinks, coffee and alcohol ​in hot weather. Alcohol and caffeine are both diuretics and causes further dehydration.

KINNECT’s injury prevention programs are focused on promoting cultural and behavioural change and stopping injuries before they occur. All our programs are tailored to your individual needs as a business. Contact us today to discuss how we can help you keep your workforce safe, healthy and productive.