How to Prevent Heat Stress at Work

There are many jobs that subject workers to a hot environment, both out of doors and inside. Doing heavy, physical labor in the heat can affect the body's cooling system. When the body is unable to cool itself, a worker can be susceptible to heat stress, and when heat stress is not recognized and treated in the beginning stages, serious or even fatal conditions can develop quickly.

Any worker who is required to do a job in hot conditions has to be prepared to deal with heat stress. During the summer months outdoor work increases, particularly in construction, roofing, forest fire fighting, forestry, and road work. Indoor work in hot environments exposes workers to heat year-round, such as pulp and paper manufacturing, bakeries, steel refining and fabricating, boiler rooms, industrial laundries and cement kilns. Workers who are exposed to these types of environments should be trained to prevent heat stress and recognize the early symptoms in themselves or co-workers.

photo from formafeed.com
photo from formafeed.com
photo from www.unconditional.co.nz
photo from www.unconditional.co.nz

What is heat stress

A human body naturally maintains an internal temperature of between 36 to 38 degrees Celsius. When the body temperature rises above this range, it will work to get rid of the excess heat. However, if the body temperature continues to rise quicker than the body can cool itself, the person could experience heat stress.

Health problems caused by heat stress are called heat disorders, and occur most commonly when heavy physical labor is done in hot and humid environments, or when the body loses too much fluid and salt due to sweating.

Primary factors that contribute to heat stress

Environment

  • air temperature
  • airflow
  • humidity
  • radiant heat - sun, kiln

Worker

  • hydration
  • clothing
  • medical conditions
  • acclimatization

Work

  • workload
  • work rate

To prevent heat stress, workers/employees need to be able to identify the variables and sources of heat, as well as how the body removes the excess.


Heat sources

There are two main ways a body can gain heat.

  1. work activity
  2. the environment

The amount of internal heat generated by a worker depends on the level of physical activity.

workload
activity
examples
light
sitting, standing, casual walking
desk work, typing, driving, supervising, assembly line work
moderate
brisk walk, moderate work, lifting/pushing
delivering mail, driving heavy machinery, fruit picking, warehousing, industrial cleaning, loading/unloading trucks
heavy
construction work, heavy lifting, pushing/pulling, climbing stairs in heavy gear
sawing/planning, digging, shovelling, restocking shelves, firefighting, roofing, sledgehammering, jackhammering
This table gives a few examples of light, moderate, and heavy workloads.

Note:

These activities do not take heat from the environment or protective clothing into account.

The amount of heat generated from the environment - external heat - depends on the air temperature, air movement and radiant heat.

Examples of radiant heat sources:

  • heaters
  • boilers
  • fires
  • sunlight
  • ground reflection/absorption

The addition of radiant heat sources can cause overheating even on cooler days.

photo from www.infraredsaunareference.com
photo from www.infraredsaunareference.com
photo from wordpress.com
photo from wordpress.com

There are two main ways the body uses to get rid of excess heat - increased blood flow and sweating. Blood flow increases as excess body heat increases which transfers the heat to the body's surface by a process known as heat exchange by convection. Working or resting in shaded areas allows the body to get rid of the excess heat by transferring it to the surrounding air.

Sweating itself does not cool the body; the cooling occurs when sweat evaporates from the skin. When air temperatures exceed 35 degrees Celsius, sweating becomes the most effective way for the body to cool itself. The amount of sweat that evaporates determines the amount of cooling to the body, therefore, any factor that hampers sweating or evaporation affects the body's ability to cool itself.

Drink Water!

It is important to drink water before, as well as during and after work in a hot environment. Workers should drink approximately two glasses of water before starting work and one glass every 20 minutes throughout the workday. Do not wait until you are thirsty!

Wear Cool Clothing!

Loose fitting, light coloured, breathable clothing reflects the heat better than dark colours, and helps keep the body cool. If safety headgear is required, attach a piece of light coloured fabric to the back and side to provide shade for the neck area.

Personal risk factors

  • lack of acclimatization - a person who regularly works in a hot environment will be at lower risk of developing heat disorders
  • poor physical fitness - being in shape helps the body cope better
  • obesity - excess fat provides increased insulation, reducing heat loss
  • increased age - in older adults (40 - 65 yrs) heart function is less efficient, sweating starts later and at a slower rate
  • pre-existing medical conditions/treatments - these can decrease a person's ability to cope with excess heat. Heart problems, low-sodium diets, diabetes mellitus, cystic fibrosis and hyperthyroidism may increase the risk of heat disorders
  • short-term disorders/minor illnesses - feverish illnesses, diarrhea, and vomiting cause excess loss of fluids, and sleep deprivation can also increase the risk of heat stress
  • chronic skin disorders - rashes, dermatitis, healed burns and other conditions that involve large skin surfaces may limit the body's ability to sweat properly
  • medications - certain medications may cause problems when working in heat stress conditions - make sure to check the potential side effects with a doctor
  • alcohol/drugs - alcohol increases water loss and can cause dehydration - some 'street' drugs can increase internal body temperature and decrease the ability to lose heat
  • previous heat stroke - workers who have previously suffered from heat stroke are at an increased risk or recurrence

Recognizing and treating heat stress

Medical Condition
Signs and Symptoms
Treatment
Notes
heat cramps
musculare pain or spasms, excessive sweating
move worker to a cooler environment, remove or loosen tight-fitting clothing, cool the worker by sponging with cool water and fanning, provide oral fluids - juice, sports drinks or solution of salt water (1 tsp of salt in one-half litre of water)
If the worker starts shivering, stop cooling. *alcohol and caffeinated beverages are not recommended* *heat cramps are only cured after the lost salt has been replaced*
heat exhaustion
shallow breathing, increased respiratory rate, weak rapid pulse, pale cool clammy skin, sweating, weakness fatigue dizziness, headache and nausea, fainting, muscle cramps (signs and symptoms are similar to mild shock)
same as above - the presence of sweating is important because it is often the only way to differentiate heat exhaustion from heat stroke
In most cases, the worker's symptoms will improve dramatically within 30 minutes - transport to medical aid
heat stroke
hot dry flushed skin, absence of sweating, agitation confusion, decreased level of consciousness, headache, nausea and vomiting, seizures, increased respiratory rate, irregular pulse rate, shock, cardiac arrest
maintain airway, breathing and circulation as required, move worker to coolest place possible, lay worker down on the back unless actively vomiting or seizuring - in this situation, place them in 3/4 prone or lateral position, remove outer clothing and apply cold water by dousing or applying wet cool sheets, spray or sponging the entire body with cold water is also effective and fanning will also help, provide oral fluids, transport worker to medical aid and continue cooling
heat stroke is a medical emergency! Notify first aid attendant, call 911 and/or arrange for immediate transportation to medical aid

Employer's responsibilities

Employers must provide adequate training and education to all workers at risk for heat stress, their immediate co-workers, and their supervisors. Employers must develop and implement a heat stress exposure plan, and conduct a heat stress assessment where the worker is, or may be working.

If a worker is exposed to environmental conditions that could cause heat disorders, the employer must implement engineering controls to reduce exposure wherever practical, or provide administrative controls or personal protective equipment, adequate first aid coverage and an adequate supply of cool drinking water close to the work area for workers exposed to heat.

Final note

Ultimately, a worker shouldn't rely on their employer for protection agains heat related illness. Many employers don't recognize their responsibilities, putting the onus on the employee to prevent heat stress on the job, so think safe and protect yourself!

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Comments 24 comments

jill of alltrades profile image

jill of alltrades 6 years ago from Philippines

What an informative hub! You really gave very useful and timely information here.

Temperature here in our country has been in the mid 30 degrees C for several weeks now. I've been bringing a bottle of water everywhere I go.

Thanks for sharing this Enelle.


saddlerider1 profile image

saddlerider1 6 years ago

You gave very informative advice about heat and the causes and remedies are well taken. I don't suffer from heat exhaustion now, but there was a day in my prime when I worked up a sweat on jobs and sports activities and I did drink a lot of water back then. Now being less active I do it all in moderation, I watch everyone else work up a sweat loss. hah


Enelle Lamb profile image

Enelle Lamb 6 years ago from Canada's 'California' Author

We are working our way up to 30 degrees C - so far the hottest this spring has been 22, but I know it's going to climb real quick! I do the same as you jill - travel with my water bottle ;)

Thanks saddlerider - I haven't suffered from heat stress yet, but my job puts me on hot asphalt in 30 degree temps...so I really need to pay attention.


RedElf profile image

RedElf 6 years ago from Canada

Very thorough hub, Enelle - you differentiated between the various symptoms and also offered first aid info. It's easy to confuse the signs, or ignore them 'til it's quite serious. Thanks for another great hub!


EllenGraeger profile image

EllenGraeger 6 years ago from Madrid

In Spain we are reaching between 40 and 45ÂșC in summer. Good air conditioning is all that helps. And you are right, Enelle, if we do not care about ourselves - our employers surely will not do it either. Thank you for this hub.


Enelle Lamb profile image

Enelle Lamb 6 years ago from Canada's 'California' Author

Thanks RedElf, I wanted to show the differences between heat exhaustion and heat stroke, as many people misdiagnose these ailments. Glad you liked the hub!

Wow Ellen, I don't think I could handle being outdoors in Spain! I have enough trouble here when the temperatures hit the 30's!


Jess Killmenow profile image

Jess Killmenow 6 years ago from Nowheresville, Eastern United States

This is a very complete and excellent hub on stress, but I must add that the best way to avoid stress at work is, don't go. Ever.

Thank you!


Enelle Lamb profile image

Enelle Lamb 6 years ago from Canada's 'California' Author

That made me laugh! Trust me, if I could get away with it, I would! Thanks for the laugh Jess, and the comment!


embee77 profile image

embee77 6 years ago

Enelle - This is an informative and timely hub for all of us, no matter what country we're in. I'm impressed with the amount of detail so everyone can find where their personal activity level fits into the symptoms, etc. Employer education on this topic is a joke in most cases. You and your coworkers have to make it a priority. The same applies to working in your yard, or any activities outside in the heat. Thanks!


Enelle Lamb profile image

Enelle Lamb 6 years ago from Canada's 'California' Author

Thanks embee77, you are so right about the Employer education - my boss is supposed to supply us with water when we are on the road in the heat - bet you know how that turns out eh?

So glad you stopped by and included the yard work and outdoor activities :D


advisor4qb profile image

advisor4qb 6 years ago from On New Footing

Interesting hub! As a Florida resident, I am always in the heat.......


Enelle Lamb profile image

Enelle Lamb 6 years ago from Canada's 'California' Author

Thanks advisor4qb, I love it when it's warm, but I'm not used to working in it!


Springboard profile image

Springboard 6 years ago from Wisconsin

I was going to say "call in sick," though eventually that might be problematic. :) Great tips here. Worked in quite a few environments where excessive heat have been a factor. Hydration is definitely a BIG plus.


Enelle Lamb profile image

Enelle Lamb 6 years ago from Canada's 'California' Author

I like the way you think Springboard! But you are probably right LOL. Today was a scortcher - made sure I had lots of water and my fan (hand held, not electric lol) to try and stay coolish.

Glad you enjoyed my tips :) and thanks for coming by to read :)


KoffeeKlatch Gals profile image

KoffeeKlatch Gals 6 years ago from Sunny Florida

Very informative. I live about an hour from Orlando and I can tell you it gets really hot here. Lots of great advice and tips.


Enelle Lamb profile image

Enelle Lamb 6 years ago from Canada's 'California' Author

Thanks KoffeeKlatch Gals, this information was almost required reading for my job and I have to say it has come in mighty handy!


paul 6 years ago

Wow what a great article now they need an article on how to keep your PC cool so it does not overheat.


Enelle Lamb profile image

Enelle Lamb 6 years ago from Canada's 'California' Author

I'm afraid I don't have any details for that, but I'm sure someone will come up with something! Thanks for stopping by :)


GmaGoldie profile image

GmaGoldie 5 years ago from Madison, Wisconsin

Very well written and exceptionally well researched Hub! Excellent! A must read and send for those who must work in the elements. Risk managers need this info.


Enelle Lamb profile image

Enelle Lamb 5 years ago from Canada's 'California' Author

Thank you so much GmaGoldie, I appreciate your comments! Being a traffic control person, this hub relates to my job. I agree - Risk managers should read this!


nms profile image

nms 5 years ago from Cochin

Very useful info. Great hub! vote up


Enelle Lamb profile image

Enelle Lamb 5 years ago from Canada's 'California' Author

Thank you nms :)


Shellby Love 5 years ago

Another good tip is to eat a lot of spicy for throughout the day it works together with the heat of your body to cool you down, and another tip is to come in about every hour to two hours or whenever your lunch break and run your wrist under cold water for about 30 secs. it also cools you down.....all of your information was very helpful for my reasearch for a safety meeting at work thank you.....


Enelle Lamb profile image

Enelle Lamb 5 years ago from Canada's 'California' Author

Most welcome! Thanks for the tips - there are a few more (for those of us who can't take breaks)

* wear a bandanna soaked in cool water to lower your temperature during the day - simply re-soak to keep cool

* wear a premade bandanna (with gel) around your neck - one soaking is generally sufficient to keep you cool all day. Simply rotate the bananna to keep the cooler side next to your skin.

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