Heat stress & awareness

What is heat stress? Heat stress is a general term which describes a variety of symptoms produced when the human body is exposed to a combination of heat and work which interferes with the body’s ability to dissipate the heat energy. Common, early, but often subtle signs of heat stress include:- Headache Disorientation / confusion Impatience / irritability Prone to making errors Dry mouth lips (already 20% dehydrated at this point) NOTE: heat stress can develop over the day and manifest in the afternoon General background information:- Normal inner core body temperature = 37 degrees Celsius Above 38 degrees = heat stress 40 degrees Celsius = life threatening / medical emergency Body is comprised of 75% water, brain 85% water

How the body works to cool itself…. Brain signals to cool the body Heat source Main form of cooling is via sweating onto the skin which then evaporates resulting in cooling THIS PROCESS CAN DEVELOP QUICKLY If untreated this will result in death Increased sweating reduces amount of salt and water in the body resulting in dehydration Eventually a state is reached where the body is unable to cool itself sufficiently and the core temperature begins to rise BACKGROUND INFORMATION FOR PRESENTERS; Heat stress can develop quickly – if you think you or one of your mates is suffering the effects tell your supervisor & seek first aid or medical assistance depending on your level of competence to act and the severity of the symptoms The process:- 1. Brain signals to cool body – main way is by sweating (sweat to skin, evaporates and cools) 2. Increased sweating reduces water and salt in body = dehydration 3. If can’t cool sufficiently – core temperature increases = changes to body and brain function 4. If untreated, this will result in death This results in changes to body and brain function

What causes heat stress? Environmental Factors Personal Factors High temperature levels Type of clothing worn High humidity Level of acclimatisation of workforce Returning from R & R New employees from countries with cooler climates Low levels of air movement State of hydration Heat sources in the area:- Heat generating / radiating equipment, appliances or structures Health & fitness:- Infection / fever Diarrhoea / vomiting Medication use Obesity Level of physical fitness Sunburnt Level & type of physical activity Excessive consumption of alcohol General background information / examples for presenter:- Examples of types of physical activities that can cause heat stress: Hot work Working in confined spaces working on roofs or in open areas exposed to sunlight / radiation Examples of PPE that may result in heat stress: Coveralls Respirators

Different types of heat stress…. There are a number of different forms of heat stress that differ in their level of severity:- HEAT STROKE Heat Exhaustion Heat Collapse Heat Cramps Heat Rash Heat Fatigue BACKGROUND INFORMATION FOR PRESENTER:- Heat fatigue Impaired performance Lapsed concentration Heat rash Often termed “prickly heat” Skin rash caused by excess sweating or the skin being wet with sweat Usually resolved with acclimatisation or removal from heat Heat cramps Painful muscle cramps of the limbs and / or abdomen, muscle twitching, tingling or pins and needles in the hands and feet May experience fatigue / nausea Salt and potassium help muscles contract and when salt levels become imbalanced due to continual perspiration or lack of water consumption (causing build up of salt) or a low salt intake (causing the opposite) the muscle contractions no longer occur normally Heat collapse Person collapses or faints due to reduced blood flow to the head When the body heats up the blood flows to the outer extremities / skin to cool the body – away from the brain Often rapid and unpredictable Heat exhaustion Heat Stroke Most severe form of heat stress Brain loses the ability to regulate the body’s temperature Body temperature rises to a critical, life threatening level (i.e.. 40 degrees Celsius +) Can quickly result in death

First aid for less severe heat stress conditions…. If heat fatigue, heat cramps or heat collapse is suspected:- Rest casualty in cool, shaded place Loosen / remove clothing Cool with wet cloth under arm pits, behind knees Direct a fan over the casualty Give cool (but not ice cold water) to drink Call for medic …. BUT WHAT IF THE SIGNS ARE MORE SERIOUS?......

Heat exhaustion vs. heat stroke – signs Dry, hot skin educed sweating Rapidly rising temperature Pupils constricted Rapid pulse Convulsions Collapse & coma Life threatening HEAT EXHAUSTION Moist, clammy skin Increased sweating Normal or subnormal temperature Pupils dilated Rapid breathing (panting) Muscle cramps Pale complexion COMMON TO BOTH Nausea & vomiting Confusion Headache Dizziness Weakness or fatigue

Heat exhaustion vs. heat stroke – management DRABC Move to a cool place Loosen tight clothing Apply cold packs / ice to areas with large blood vessels Cover with wet sheet and fan Do not give fluids unless casualty is conscious SEEK IMMEDIATE EMERGENCY MEDICAL ASSISTANCE HEAT EXHAUSTION Move to a cool place Offer sips of cool water if the casualty is conscious Call for medical assistance

Methods of prevention.... Remove heat source, e.g. Shut down heat generating equipment Reschedule work to a cooler time of the day Increase air movement, e.g. fans Erect structure or heat shields around hot components Slip-slop-slap Erect shade shelters or work in shaded areas if possible Training / education Use of appropriate PPE, e.g. wide brims over hard hats Note risks and controls in JHA’s Employee rotation Suitable work pace Be aware of location of nearest potable water Take regular breaks in shade or air conditioned crib rooms YOU Aware of physical limitations Be alert to subtle symptoms in you and workmates Raise any concerns with supervisor – if feel unwell Be aware of first aid for heat stress Hydrate – 100-200ml of water at frequent intervals lost body fluid in hot conditions can be as high as 1-2 litres of water an hour Avoid alcohol / caffeinated drinks – lose even more water / salt Eat light, cool lunch – hot, heavy meals can reduce your ability to release heat Apply sunburn cream to all exposed skin areas

What more can you do? Be aware of your own physical limitations and general health / fitness status Be alert to subtle symptoms in you and your workmates Raise any concerns or feelings of ill health with your supervisor Be aware of first aid for heat stress Hydrate – drink100-200ml of water at frequent intervals i.e. 15 mins (lost body fluid in hot conditions can be as high as 1-2 litres of water an hour) Avoid alcohol / caffeinated drinks – you will lose even more water / salt Eat light, cool lunches or snacks – hot, heavy meals or snacks can reduce your ability to release heat Apply sunburn cream to all exposed skin areas – burnt skin will hold in heat Give yourself time to acclimatise – whether you are back from a short break or are completely new to conditions BACKGROUND INFORMATION FOR PRESENTERS: Acclimatisation – gradually increasing the amount of time you spend working in a hot environment. It takes about 1-2 weeks for the body to adjust to heat Acclimatisation is quickly lost – if you are away for a period of 14 days for example

hydration Monitor the colour of your urine The darker coloured your urine, the more you need to drink This is quite a late sign showing that you are already dehydrated Drink regularly in small amounts rather than waiting until you are thirsty Drink water before you commence work and continue to drink Reduce your intake of caffeine and alcohol (e.g. Red Bull, coffee, beer etc.) Drink cool rather than cold fluids – cold fluids can cause stomach cramps

IN Summary Working in hot environments is a common element of working in Australia…. TAKE THE TIME TO STOP! Consider the risks – CONTROL THEM! Lets all go home safely every day

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