Heat, hydration and outdoor work.

Summers here are hot, and a good number of people work through them outdoors — on sites, on machinery, in yards and paddocks. Heat illness usually builds gradually, and the early signs are easy to talk yourself out of noticing — but it does not always announce itself, and it can move fast.

Know the difference between the two

This distinction matters more than anything else on this page.

Heat exhaustion

The body is struggling but still coping. Someone with heat exhaustion is typically sweating heavily, pale and clammy, weak, dizzy, nauseated, with a headache, cramping muscles and a fast pulse. They are still making sense.

What to do: stop work immediately, get them somewhere cool and shaded, lie them down with their legs raised, loosen clothing, cool them with water and airflow, and give cool fluids in small sips if they are fully alert. They should not go back to work that day, and someone should stay with them.

If they are not clearly improving within about ten minutes, or they are vomiting, cannot keep fluids down, or become confused or drowsy at any point — call 000. Heat exhaustion progresses to heat stroke, and the handover point is the moment they stop improving.

Heat stroke

The body's temperature control has failed. This is a medical emergency and people die from it.

The distinguishing feature is a change in how the person is behaving and thinking — confusion, slurred speech, unusual aggression or agitation, stumbling, collapse, seizure or loss of consciousness. The skin may be hot and dry, but it can also still be sweaty, so do not use dry skin as your test. Trust the confusion.

Call 000 immediately. Then start cooling without waiting. Get them into shade and remove excess clothing. If you can immerse them — a bath, a trough, a tub — cold water from the neck down is the most effective thing you can do. If immersion is not possible: cold water over the body, wet cloths, ice packs to the armpits, groin, cheeks, palms and soles, and as much airflow as you can manage. Do not give fluids to anyone who is confused or drowsy. Cooling early makes a real difference to the outcome.

Drinking, and why thirst is not a good guide

By the time you feel thirsty, you are already behind. On a hot working day, drink to a schedule rather than to thirst — regular amounts through the shift rather than a large volume at smoko.

Water is fine for most situations. If you are sweating heavily for hours, you are losing salt as well as water, and replacing only the water can cause its own problems — food at breaks and an electrolyte drink both help. Watch out for energy drinks, which are often the default on site and are heavily caffeinated.

Urine colour is a rough but workable check: pale is fine, dark means drink more.

Who is at more risk

• Anyone not yet acclimatised — new starters, people back from leave, and everyone during the first hot spell of the season. Acclimatisation takes one to two weeks of gradual exposure.
• Older adults and young children.
• People with heart disease, lung disease, diabetes or kidney disease.
• People taking certain medicines — diuretics, blood pressure medicines, some antidepressants, some antipsychotics, and anticholinergics can all reduce your ability to shed heat. This is worth reviewing before summer rather than during it.
• Anyone who has been drinking alcohol, or is unwell with a fever or gastro.
• People working in heavy PPE or a respirator, which traps heat.
• People who had heat illness previously — it makes recurrence more likely.

Sensible habits on hot days

• Get the heaviest work done early, and build in more breaks than feel necessary.
• Take breaks somewhere genuinely cooler — shade or air conditioning, not just out of direct sun.
• Light, loose, breathable clothing where the job allows, plus a wide brim and sunscreen.
• Work in pairs and watch each other. People are far better at spotting confusion in someone else than in themselves.
• Never leave anyone — or any animal — in a parked vehicle.
• At home, close up during the day, open up at night, and check on older neighbours during a heatwave.

Afterwards

Anyone who has had a significant episode of heat illness should be reviewed. It is worth checking kidney function and electrolytes, going through medicines, and thinking about whether an underlying condition made it more likely. Book a standard appointment and say what it is about.

General information only. This article is general health information for anyone who finds it useful. It is not advice about your own situation and it does not replace a consultation with a doctor who knows you. If you are worried about a symptom, book an appointment or call us on (02) 6530 7404. Last reviewed 23 June 2026.