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Health effects

Heat strain can prevent normal cooling mechanisms from working properly and can lead to heat-related illnesses.

People have an average core body temperature of around 37˚C. In hot environments, or where internal temperature is raised through exercise for example, body responses include:

Normal responses

  • vasodilation (widening of blood vessels)
  • sweating
  • increased respiratory rate
  • increased heart rate.

Responses due to heat strain

  • electrolyte changes
  • dehydration
  • elevated core temperature.

Excessive heat strain can occur when the work environment, task or individual health prevent these cooling mechanisms from working properly, and can lead to heat-related illnesses including:

  • Heat rash – sometimes called 'prickly heat'. It is a skin irritation caused by excessive sweating and:
    • can occur at any age
    • is most commonly associated with humid /dusty tasks in which the skin pores become blocked
    • looks like a red cluster of pimples or small blisters
    • is most likely to occur on the neck and upper chest, and in skin folds and creases.
  • Heat cramps – these include muscle pains or spasms, usually in the abdomen, arms or legs. They may occur after strenuous activity in a hot environment, when the body gets depleted of salt and water. They may also be a symptom of heat exhaustion.
  • Dizziness and fainting – heat related dizziness and fainting results from reduced blood flow to the brain. Heat causes an increase in blood flow to the skin and pooling of blood in the legs, which can lead to a sudden drop in blood pressure.
  • Heat exhaustion – is a serious condition that can develop into heatstroke. It occurs when excessive sweating in a hot environment reduces the blood volume. Warning signs may include paleness and sweating, rapid heart rate, muscle cramps (usually in the abdomen, arms or legs), headache, nausea and vomiting, dizziness or fainting.
  • Heatstroke – is a medical emergency and requires urgent attention. Heatstroke occurs when the core body temperature rises above 40.5 °C and the body's internal systems start to shut down. Many organs in the body can suffer damage and to rectify it, the person's body temperature must be reduced quickly. Most people will have profound central nervous system changes such as delirium, coma and seizures. The person may stagger, appear confused, have a fit or collapse and become unconscious. As well as effects on the nervous system, there can be liver, kidney, muscle and heart damage. The symptoms of heatstroke may be the same as for heat exhaustion, but the skin may be dry with no sweating and the person's mental condition worsens.

Watch the film A Current Affair - Melting Man, below on this webpage, that outlines the tragic consequences that can occur if heat strain factors are not adequately controlled.

A Current Affair - Melting Man

This story shows the tragic consequences that can occur if heat strain factors are not adequately controlled. Story provided to Workplace Health and Safety Queensland courtesy of the Nine Network's A Current Affair program.

Download a copy of this film (MP4, 221MB)


Mr Martin King, Current Affair Journalist

Mr Alan Byrne

Mrs Bernadette Byrne, Mother

Mr Des Byrne, Father

Mrs Karen Simpson, Lawyer, Slater & Gordon

Dr Andrew Heggie, Associate Professor, Facial Surgeon

Martin King: Hey mate, how are you going?

Alan Byrne: Good.

Martin King: Can you stand up?

Alan Byrne: Yeah.

Martin King: Want to have a crack? Do you want me  to – are you right?

Alan Byrne: I'm right.

Martin King: Good man.

Alan Byrne: Okay.

Martin King: How does that feel?

Alan Byrne: Good.

Bernadette Byrne: Alan was always a great worker,  always. He had rung me the weekend before and said "Mum I'm working really  hard".

Martin King: What is your memory of that day in  Queensland?

Alan Byrne: Oh God, none.

Martin King: No memory at all?

Alan Byrne: No.

Martin King: Who would want to remember? On a  stinking hot Queensland day Alan Byrne almost worked himself to death. He can't  remember because he's brain damaged from heat stroke.

Bernadette Byrne: Alan's been through everything you  could imagine, from being in a coma, on death's doorstep, to now going through  a process of rehabilitation to get his life back.

Des Byrne: G'day Alan, how are you?

Alan Byrne: Good.

Bernadette Byrne: What are we watching today?

Des Byrne: These soapies again.

Martin King: The days of Alan's life are so  different now. The big, strong brickie's labourer is back in Melbourne with his  parents, Des and Bernadette. What is it like for you two to see  your son like this?

Bernadette Byrne: Oh, it's heartbreaking, it's  heartbreaking, because we know what he was like and we want him back that way,  but we can't.

Martin King: What happened that day on a building  site is a warning to all of us about the dangers of heat stroke. It was 42  degrees. Alan had been working in the full sun all day. He hadn't had enough  water, he hadn't had any food, he wasn't wearing a hat. At 3:00 o'clock in the  afternoon he started feeling sick and began walking home, five kilometres. He  didn't make it. He was found unconscious at a roundabout by a bus driver, who  called police.

Bernadette Byrne: This is in Queensland.  Said he's critically ill, you need to get here. But don't come here, go to  Townsville because we're airlifting him because he's critically ill. We just  went into panic, we were all just shaking and crying.

Martin King: When Des and Bernadette arrived at  Townsville Hospital their son was in a coma.

Bernadette Byrne: It hit us, didn't it?

Des Byrne: Yeah.

Bernadette Byrne: We saw our son there, dying really.  They told us he was dying. On total life support, total life support. There  wasn't one part of his body that wasn't on some machine.

Martin King: Tell me what happened to your son's  body.

Bernadette Byrne: It completely shut down, everything  shut down. His body, well, it boiled, it boiled. Even they told us the bone  marrow boiled. It was so overheated. His body temperature was 42 degrees,  that's why he couldn't – they said he wouldn't live.

Karen Simpson: In Alan's case the employer has  failed to ensure that he was adequately hydrated and protected from such  extreme conditions.

Martin King: Karen Simpson from Slater &  Gordon in Brisbane is Alan's lawyer. His case is now one of Australia's biggest  WorkCover claims.

Karen Simpson: It's certainly a catastrophic sized  claim. Because of the lack of residual earning capacity for Alan, it will  result in very significant monetary compensation for him.

Des Byrne: One of the surgeons said "You don't  know it's happening to you until someone comes up behind you with a baseball  bat and goes whack, and that's it and you're down".

Martin King: It was the capable hands  of doctors in Townsville that saved Alan's life, but then a shocking complication.  He lost blood supply to his face and his facial bones began to dissolve.

Dr Andrew Heggie: Absolutely unusual, quite unique.

Martin King: Dr Andrew Heggie specialises in  facial surgery.

Dr Andrew Heggie: The three major components have been  replaced. There's the bone from the hip to replace the upper jaw. A rib graft  to reconstruct the nasal bridge and the contour. Then subsequently these  titanium implants so that a full bridge can be made to reconstruct his jaw and  bite.

Martin King: What is the one thing you would like  to do with your body?

Alan Byrne: Walk.

Martin King: Walk. Alan's legs are strong and  capable, it's the brain damage that's the problem.   What are your hopes for the future?

Alan Byrne: Work.

Martin King: What would you like to do for work?

Alan Byrne: Anything.

Martin King: Just anything? If you  can't work you might as well work out. Or go shooting. Or sailing. What is Alan's future?

Bernadette Byrne: Who knows? You've got to leave all  the doors open. Who knows? He's still our son and he's still absolutely  beautiful.

~ The End ~

Run time: 4:36