As summer approaches and the hot and humid weather returns, a quick discussion regarding heat induced illness is in order. While the bulk of our job is spent in an air conditioned cab and we probably don’t have a tremendous amount of physical exertion throughout the day, you may find yourself having to do physical labor to unload your trailer on a hot and/or humid day.  In this situation you should know the signs and symptoms of heat induced illnesses: heat cramps, heat exhaustion and heat stroke. When the body is unable to cool off by sweating, those three medical conditions can occur.
Heat induced illness can be caused by any or a combination of the following:

  • direct sun
  • high temperatures/oven-type heat 
  • high humidity 
  • dehydration
  • electrolyte imbalance 
  • exposure to constant moisture 
  • workload intensity or strain 
  • physical fitness 
  • age
  • metabolism rate
  • medications
  • alcohol/drug use
  • limited air movement and acclimatization (10-14 days to become acclimated and only 2 days to lose acclimatization)

The first stage of heat induced illness is heat cramps.

  • General symptoms of heat cramps: painful spasms in the legs, arms or abdominal muscles, heavy sweating and thirst.
  • Causes: Heat cramps typically occur after hard work or exercise and are caused by electrolyte deficiencies that result from extended periods of intense sweating.
  • First Aid: Stop all activity and sit in a cool place.  Drink plenty of water and electrolyte fluids in a 3:1 ratio (three waters to one electrolyte fluid).  Do not return to strenuous activity for a few hours after the cramps have subsided.

The second stage of heat induced illness is heat exhaustion and this is more serious than heat cramps.

  • General symptoms of heat exhaustion: headache, rash, cramps, physical exhaustion/weakness, cool, clammy or moist skin, heavy sweating, mood swings or erratic behavior, nausea or vomiting, dizziness or fainting, increased stress on body organs and a core body temperature up to and including 103 degrees Fahrenheit.
  • Causes: All of the causes listed above for heat cramps and also dehydration, lack of acclimatization, reduction of blood in circulation, strain on the circulatory system and reduced blood flow to the brain.
  • First Aid: Rest in a cool shady place and drink plenty of water plus electrolyte fluid.

The third and final stage of heat induced illness is heat stroke.  Heat stroke is considered a true medical emergency and is immediately life threatening.  Heat stoke happens when all of the body’s cooling mechanisms have been exhausted so your body can no longer cool itself and your core body temperature ranges from 104 to 110 degrees Fahrenheit.  When heat exhaustion is not treated and stopped, heat stroke is very likely to occur.

  • General symptoms of heat stroke: extremely rapid pulse, high body temperature, red, hot, dry skin with a lack of perspiration, nausea, dizziness and confusion, a strong and rapid pulse, seizures or convulsions, delirium, loss of consciousness, coma and finally death.
  • Causes: All of the causes listed above for heat cramps and heat exhaustion.  It is worth noting that heat stroke can occur suddenly if heat exhaustion is not treated and can be fatal.
  • First Aid: A person suffering heat stroke needs immediate medical attention and should be taken to a medical facility immediately.  Brain damage is very possible.  Call 911 immediately and move the person to a cool shaded area.  Douse the person continuously with cool water and fan them but take great care not to compromise their airway.  While waiting for EMS to arrive the goal is to bring their core body temperature down to the 101 to 102 degree range.

There is a very short phrase used in the fire industry and it applies here as well and that phrase is “Situational Awareness”.  Be aware of your situation such as how physically strenuous your work level is, heat, humidity and acclimation to the environment.  Pay attention to your body physiology.  Your body will tell you what is happening if you are tuned in and listening.  Know your physical limitations and do not exceed them. 

Take note of the different symptoms in each category listed above; some symptoms are the same while others are very different and should clue you in to what is happening. Always remember your main goal is to provide for your family and part of that is going home safe and healthy, after all it is just freight and the world won’t stop if it doesn’t get unloaded in record time.

Comments (9)

Craig McCue

Business owner and part-time operator of a seasonal business.

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Thank you for sharing your experience. Heat induced illnesses are a serious problem and they do come on fairly quickly. I'm glad you were able to get to a hospital for treatment. You hit on a point that I didn't make in the article and that is that it can take several days to recover if the heat illness goes to the point of needing medical attention. The sad part of your story is the shipper didn't have compassion for your situation. I'm glad they have a temperature controlled waiting area now but think about what it cost you before they decided to provide an area. I hope your carrier and/or the shipper picked up the medical and hotel bills for both of you but sadly that doesn't make up for the lost revenue.
On a positive note, both of you now know more about heat illnesses and where your heat limits are. I hope this situation doesn't happen to you again and I hope your story here helps others to be aware. Thank you, stay safe and stay cool!!!

June 27, 2014 8:15:57 AM

We were both hospitalized for heat exhaustion last year. Unfortunately the shipper had nowhere for us to wait inside, we were in our truck for 5+ hours waiting to be loaded in 117° weather. Granted we ran the apu and ac, it wasn't enough to keep up. We called multiple times and talked to dispatch and told them that this was unacceptable and both of us were starting to not feel well. This went on for hours, until it was too late.

We were drinking water, pedialyte, cooling ourselves with rags, frozen foods, and still got sick. I nearly passed out before we left to go to the hospital. I received 2 liters of fluids once they were finally able to obtain nan iv, was cooled with cold rags, and bags of cool fluids. My body temp was 102.3 degrees. It is something I will never forget. We then spent the following 5 days in a hotel room recovering before I felt well enough to drive. Thankfully that shipper now has a waiting area so it will not happen to anyone else.

It truly is a horrible feeling.

June 27, 2014 6:33:37 AM

As drivers we have to be extra careful of heat especially if the A/C in your truck goes out. It has happened to me a few times and by the end of the driving day I have felt very run down even if it was not all that hot out. I often wonder how drivers handled the heat back in the pre A/C days and stayed safe driving.

June 21, 2014 7:12:22 AM

Linda, I also would say you were lucky, very lucky. The take away is that you learned from it. Heat related illnesses come on sudden and by that I mean you can be doing something physical and be hot but not feel bad. Then all of a sudden, wham, it'll hit you and you'll feel lousy and it will get worse in a hurry.
Even people that live in hot and/or humid environments are susceptible to heat related illnesses but those of us that are from more moderate climates are more quickly susceptible.

June 06, 2014 13:48:40 PM

Being from the desert heat was always part of my life and something we dealt with and moved on. A few years ago I gave myself a scare in Las Vegas while I was out walking. As usual I did not pay any attention to the heat and I felt like going for a walk and I went to far. Even though I had brought water I did not bring enough and I took myself right to the edge of having a serious problem. I pay a lot more attention to the heat now and I am lucky I had a second chance.

June 06, 2014 5:52:04 AM

You're right, humidity drastically increases the chances of heat related illness. Sweating by itself doesn't cool the body unless the sweat evaporates. It's the evaporation at the skin surface that creates cooling, known as evaporative cooling. This action cools the venous blood on it's return trip into the body and that cool blood absorbs heat and the whole process continues. It's the same principle in our refrigerators and air conditioners. Hot and humid weather causes us to sweat profusely but evaporation can't occur if the atmosphere is already saturated with moisture. In this situation all that happens is we continue to heat up and can easily become dehydrated from profuse sweating.
Here is a gross statistic, maximum sweat rates for an adult can reach up to 2-4 liters per hour, that's a maximum not an everyday occurrence. That can be 10-14 liters per day which equals 10.5-14.7 quarts and that is difficult for me to imagine. All I can say is ooowh! I've been in some pretty hot and humid environments for extended periods but I know I've never come close to those levels. Sweating at that rate would require close monitoring of liquid intake and mineral replacement not to mention all the skin chaffing due to your wet cloths dragging on your skin. My guess is your time in Iraq with all the gear you wore would be much closer to those levels than anything we would see here.

June 05, 2014 14:04:42 PM

Very good suggestions, thank you! I do believe the pre hydrating is a good solution for planned short duration exertions such as running a marathon, but how would that work for prolonged exposure? I'm not sure I could drink that much regularly, but I like the idea. Cooling the armpits and crotch work well because those areas have large veins that are relatively close to the skin and cooling the blood returning to the heart decreases your core body temperature. It's very effective and I'm glad you mentioned it.
Speaking of marathons, one of these days you should book a load to Eugene and run in the Eugene Marathon. This year it is July 27th. It is a 26.2 mile race that ends at historic Hayward Field at the University of Oregon, right here is Track Town USA. There is also a 1/2 marathon and a 5K run.

June 05, 2014 13:43:18 PM

Great blog Craig. One thing I've learned is 90* in a humid area is worse than 115* with no humidity.

June 05, 2014 7:29:41 AM

This is a timely article. I saw this happen in the Green Bay marathon a few years ago. They had to shut down the race because of an ambulance shortage. One thing to do is to pre hydrate. Their are 2 places on the body to cool down first, with ice or cold wet wag, one is the armpits. The other is the crotch. Unless you know the person or are a pro, use the pits?

June 05, 2014 4:45:09 AM