In brief
The most important sign that distinguishes heat stroke from heat exhaustion is a change in consciousness and behaviour: confusion, nonsensical speech, staggering, seizures or fainting. If any of these signs is present, 112 is called and the worker is cooled immediately while waiting for the ambulance. In heat exhaustion, the worker is moved away from the heat, rested and given fluids; if they do not improve or get worse, it is also treated as an emergency.
Are heat stroke signs only seen in summer?
Heat stroke is mostly associated with the summer months, but in the workplace the risk depends on the work, not the calendar. Furnace areas in foundries, forging and heat treatment, ovens and bakeries, boiler rooms, stenters and drying machines in textile finishing, industrial laundries and large kitchens are hot environments in every month of the year. In workers wearing chemical protective suits, aluminised clothing or heavy PPE, body temperature can rise quickly even if the ambient temperature is not high.
Annex I Art. 20 of the Regulation on Workplace Buildings and Annexes requires measures to protect workers where, by the nature of the work, they must work continuously in very hot or very cold environments. An important part of these measures is a team that can recognise a worker affected by heat early and respond correctly. This article explains the signs of heat stroke and the response in a way that a co-worker alongside can apply. Measuring and correcting environmental conditions is a separate subject; we covered it in our article on thermal comfort measurement.
The stages of heat stress
The effect of heat on the body progresses from mild to severe. Each stage can be a warning of the next:
| Condition | Typical signs | Consciousness | First action |
|---|---|---|---|
| Heat syncope | Brief dizziness or fainting after standing for a long time or getting up suddenly | Recovers quickly when lying down | Lay them down somewhere cool, raise the legs, give fluids |
| Heat cramps | Painful contractions in the leg, arm or abdominal muscles after heavy sweating | Normal | Rest, cool down, give fluids containing water and salt |
| Heat exhaustion | Heavy sweating, pale and clammy skin, weakness, headache, nausea, vomiting, thirst, rapid pulse | Normal; the worker can describe how they feel | Move away from the heat, loosen clothing, cool down, give fluids; monitor |
| Heat stroke | Marked rise in body temperature; hot skin (may be dry or sweaty); confusion, nonsensical speech, staggering, seizures, fainting | Impaired | Call 112 and start cooling without delay |
Heat stroke is a life-threatening emergency. The other three conditions usually improve with rest and cooling, but can progress to heat stroke if work continues.
Heat exhaustion or heat stroke?
There is often no thermometer on site, and measuring body temperature accurately is not easy either. So make the distinction based on behaviour. Ask the worker simple questions: What is their name, where are they, what time is it, what job were they doing? If the answers are inconsistent, their speech is impaired, they cannot stand or they are behaving differently from usual (irritability, purposeless movements), assume heat stroke.
The main differences between the two conditions:
- Heat exhaustion: The worker is tired but conscious; they recover after resting somewhere cool and taking fluids.
- Heat stroke: Consciousness is impaired; it does not resolve by itself with rest, and rapid cooling and hospital treatment are needed.
Heat stroke first aid: cooling steps
When heat stroke is suspected, time is critical. Cooling carried out while waiting for the ambulance directly affects the outcome. Apply the steps as a team:
- Call for help: One person calls 112 and the others begin the response. In the call, clearly state "worker in a hot environment at a workplace, consciousness clouded" and the address.
- Move away from the heat: Move the worker to a shaded or cool area away from the furnace, oven or machine. Prevent them falling while being moved.
- Undress: Remove the hard hat, protective suit, apron, gloves and thick clothing; loosen tight parts.
- Wet and ventilate: Wet the skin with cool water or cover with wet towels and sheets; apply a continuous fan or airflow. Replace a wet cover with a fresh one as it warms up.
- Cold application: If available, place ice packs or cold compresses on the neck, armpits and groin.
- Check consciousness: If the worker is awake, able to swallow and not vomiting, give cool water in small sips. If they are unconscious, give nothing by mouth, monitor breathing and place them on their side.
- If there is no breathing: Start basic life support.
- Continue until the ambulance arrives: Do not stop cooling until the team arrives, even if the worker comes round, and do not leave the worker alone.
In heat exhaustion the first three steps are the same: moving away from the heat, loosening clothing and cooling. Because the worker is conscious, they can take fluids. If the symptoms do not improve quickly, they cannot take fluids because of vomiting or their condition worsens, 112 is called.
Deciding to call an ambulance
If any of the following is present, call 112 without waiting:
- Confusion, nonsensical speech, inappropriate answers to questions,
- Staggering, unsteadiness, inability to stand,
- Seizures, convulsions,
- Fainting or being unrousable; fainting that does not resolve quickly on lying down,
- Inability to take fluids because of vomiting,
- Chest pain, shortness of breath or an irregular pulse,
- Heat exhaustion that does not improve or worsens despite cooling and rest.
When deciding, do not rely on the worker saying "I'm fine, it'll pass after a little rest". In heat stroke, the person may not be able to judge how serious their condition is.
Early recognition on site: the buddy system
A person suffering heat stroke often cannot recognise their own condition; the first signs are seen by the co-worker next to them. Pair up workers in hot departments and give each of them these duties:
- Observing their buddy's speech and movements throughout the shift, and stopping work when they notice absent-mindedness, staggering or nonsensical answers,
- Checking whether their buddy is drinking water and taking their breaks,
- In work done in heavy PPE, planning PPE removal breaks together,
- Knowing in advance who will call 112 and who will start cooling if someone is taken ill.
New starters, those returning from long leave and subcontractor workers entering a hot environment for the first time are less acclimatised to heat in their first days. Pair these workers with someone experienced and keep their working time short in the hottest tasks, such as at the furnace, in the first days.
What not to do
- Giving water or any other drink to a worker whose consciousness is clouded or lost,
- Giving fever-reducing medication: it does not lower body temperature in heat stroke,
- Rubbing with alcohol-based lotion or cologne,
- Trying to send the worker to hospital in a company vehicle without cooling them, or pausing cooling while waiting for the ambulance,
- Leaving a worker who has been taken ill to rest alone in the changing room,
- Allowing the worker to return to the furnace or to driving the same day after recovering.
Put it in the emergency plan
For every department with a hot environment, heat stroke should be treated as an emergency scenario:
| Plan element | Application |
|---|---|
| Scenario | In which departments, in which jobs and with which PPE the risk increases is written down |
| Team | A certified first aider on every shift. One first aider for every 20 workers in less hazardous, every 15 in hazardous and every 10 in very hazardous workplaces |
| Supplies | Cool rest area, fan, towels, water container, cold compresses; checked together with the first aid cabinet |
| Communication | Who calls 112, how directions to the address are given, which gate the ambulance uses |
| Drill | A heat stroke scenario can be added to one of the annual drills |
| Records | Incident, response and hospital referral report; assessment of whether the incident must be notified as a workplace accident |
For workplace accident notification deadlines and reports, see our article on what to do after a workplace accident. We described other risks in continuously hot environments such as foundries in our article on workplace safety in foundries.
We prepare emergency scenarios for departments with hot environments under our emergency plan service; we carry out health surveillance and return-to-work assessments for workers in hot conditions under our workplace physician service.
Frequently Asked Questions
What are the signs of heat stroke?
A marked rise in body temperature, hot skin, a rapid pulse and, most importantly, a change in consciousness: confusion, nonsensical speech, staggering, seizures or fainting. If these signs are present, heat stroke should be considered even if the worker is sweating.
How are heat exhaustion and heat stroke told apart?
In heat exhaustion the worker is weak, sweaty and nauseous but conscious. In heat stroke, consciousness and behaviour are impaired. If there is a change in consciousness, 112 is called and cooling is started immediately.
What should be done for a worker who faints in the heat?
They are laid down somewhere cool, their legs are raised and their clothing is loosened. If they come round quickly and can swallow, fluids are given. If consciousness does not recover quickly or confusion persists, 112 is called.
When can a worker who has had heat stroke return to work?
After a hospital assessment, with the workplace physician's return-to-work assessment. They should not return to a hot environment or risky work the same day.
A physician assigned for the time your hazard class requires: pre-employment and periodic examinations, fitness-for-work reports and health surveillance.
Bursa SİSTEMER OSGB Technical Team — written from the field experience of our OHS specialists and workplace physicians. Legal information is valid as of the publication/update date; contact us for an assessment specific to your business.