Protecting Field Workers in the Summertime Heat

Protecting Field Workers in the Summertime Heat

by Nicole Moyen

You can see the original article in T&D World, here.

Utilities’ and contractors’ field crews must often work in extreme heat during the summer months. Here is how to recognize symptoms of heat stress.

You’ve likely experienced a hot day working in the heat. You’re hot, thirsty, tired, and sweaty, and the work that you’re used to doing feels even harder. But why?

Your body wants to maintain a really tight temperature range: ~3-4°F or 2-3°C. But even increasing your body temperature by 1-2°F can have a big impact on your body’s physiological responses. Your body temperature goes up when you are accumulating heat faster than you can get rid of it.

You can accumulate heat from the environment, like when it’s really hot and humid outside, or when you’re exercising or working really hard in the heat. When you’re working or exercising, your muscles produce heat as a byproduct of the movements you’re doing. In response to this increase in heat production, we increase blood flow to the skin (to move heat from the body core to the skin) and start sweating to get rid of body heat.

However, if you’re producing heat faster than you can get rid of it, your body temperature will go up. As your body temperature gets higher, you will sweat more too in order to try to get rid of more heat. The hitch is that the sweat must be evaporating off of you to cool you down and reduce your core body temperature (i.e. dripping sweat doesn’t cool you down). As you’re sweating more, you’re losing more body water.

Your blood is made up of ~50% water, and so when you lose this water through sweating, your blood volume goes down. This is a problem because you need blood to go to the working muscles in your body for energy. Your blood carries oxygen, which is essential for your muscles to create the energy they need to keep working. This also means that you have less blood going to the skin to get rid of heat. As a result, your heart (which pumps the blood) has to work even harder to get the same amount of blood to your working muscles and to the skin. This means that your heart rate will be higher when working in the heat vs. working in a comfortable environment.

The loss of water (and therefore blood volume) through sweating is one of the reasons staying hydrated is so important. By replacing the fluids you’re losing through sweating, you can help your heart rate to stay lower during your work in the heat. In turn, this will allow you to work harder in the heat–simply by staying hydrated.

If you’re not staying hydrated on the job, not only will you have a higher heart rate, but you will feel more fatigued, and are more likely to be in a bad mood (frustrated, angry, etc), and you might also experience some “fogginess” in your thinking. So make sure that you’re taking frequent breaks, drinking plenty of fluids, avoiding alcohol, and eating healthy foods.

Most importantly, if you start to experience any of the signs and symptoms of heat injury or illness, be sure to stop working right away and take a break. These are early warning signs that your temperature is getting too high and you need to slow down and take a break. Remember that heat illness can lead to exertional heat stroke and even death. Take any signs and symptoms seriously.

Monitoring your heart rate with smart PPE or a chest strap can help you to know if you might be dehydrated, because your heart rate will be higher than normal for the same workload. Make sure that you are staying aware of how you’re feeling throughout the day, and have a buddy to check in with and talk to so that you can make sure you are both doing okay on really hot, humid days.

Drink plenty of fluids, stay cool, and pay attention to your body and any warning signs it might be giving you to stay safe in the heat.

SHELTER-IN-PLACE ORDERS COULD LEAD TO MORE HEAT-RELATED DEATHS AT WORKSITES

SHELTER-IN-PLACE ORDERS COULD LEAD TO MORE HEAT-RELATED DEATHS AT WORKSITES

2020 is projected to be one of the hottest years on record,

which might be OK if you have air conditioning and work indoors.

But it could be hazardous if you work in the heat & have been sheltering-in-place. We tell you why.

At Kenzen, we believe that the hottest year on record combined with the COVID-19 pandemic will lead to even more heat-related deaths at worksites if employers don’t take the proper precautions.

Employers should not only be screening their workers for COVID-19 related symptoms, but be monitoring them for signs & symptoms of heat injuries & illnesses while at work. Why, you might ask?

7 Day Forecast in the 90s

With shelter-in-place orders across much of the globe, many people who work manual labor jobs are forced to stay home to avoid spreading COVID-19.

This means that many workers are likely spending most of their days in air-conditioned homes instead of working outside (as normal). This is problematic because research shows that those accustomed to air-conditioned homes are less tolerant of the heat.

Most heat-related deaths occur in the first few days of working on a job site in the heat. And one of the best ways to mitigate heat-related injuries & illnesses is to acclimatize to the heat. Many workers naturally acclimatize to the heat during the early summer (e.g. May & June) when temperatures start to increase, however, with shelter-in-place orders around the globe, this acclimatization period could be erased.

Instead, workers that have been sheltering-in-place during the early summer will likely be asked to go back to work in mid-July or August, in the dead-heat of the summer when they haven’t had a chance to acclimatize. On top of that, they will be asked to make up for “lost time” on the worksite. This means that not only will workers be asked to work harder when returning to the site, but they likely won’t be given the necessary time (~2 weeks) to acclimatize to the heat.

This is a recipe for disaster, that will likely lead to an increase in the number of heat-related deaths, injuries, and illnesses.

Oil field

SO WHAT CAN YOU DO TO PROTECT YOUR WORKERS?

  • Gradually ramp up their workloads each day & the amount of PPE that they’re wearing

  • Provide cooling stations & plenty of breaks in the first few days

  • Monitor your workers for signs & symptoms of heat-related injuries & illnesses during their first week back on the job site. The use of physiological monitoring of each individual can help to know when workers are getting too hot & need to take a break.

Let Kenzen help you in these crazy times. With our individualized physiological monitoring device, we make it so that you have one less thing to worry about and you can just focus on the task at hand.

Most importantly, we at Kenzen hope that you all stay safe, stay healthy, and stay cool.

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References:

  • Williams, Augusta A., et al. “Building Vulnerability in a Changing Climate: Indoor Temperature Exposures and Health Outcomes in Older Adults Living in Public Housing during an Extreme Heat Event in Cambridge, MA.” International journal of environmental research and public health 16.13 (2019): 2373.

  • Bain, Anthony R., and Ollie Jay. “Does summer in a humid continental climate elicit an acclimatization of human thermoregulatory responses?.” European journal of applied physiology 111.6 (2011): 1197-1205.

  • https://www.theguardian.com/environment/2020/apr/27/meteorologists-say-2020-on-course-to-be-hottest-year-since-records-began

3 THINGS YOU NEED TO KNOW ABOUT WORK/REST SCHEDULES

3 THINGS YOU NEED TO KNOW ABOUT WORK/REST SCHEDULES

WORK/REST SCHEDULES CAN HELP PREVENT HEAT INJURY & ILLNESS ON HOT DAYS.

BUT THERE ARE 3 IMPORTANT THINGS YOU NEED TO KNOW BEFORE ADMINISTERING THESE SCHEDULES TO YOUR WORKFORCE.

Construction worksite

  1. These work/rest schedules are not “one size fits all.” What does this mean? Well that a work/rest schedule of 30 minutes working and 30 minutes resting on a really hot day is not going to prevent heat injury or illness in ALL people. The research backing these work/rest schedules has largely been based upon young, healthy men, which means that other populations (older individuals, women, diseased populations) might need very different work/rest schedules.

    “…existing guidelines adopted and recommended for use by government agencies worldwide (e.g., WHO, CDC, others) to protect the public and workers also assumes a “one size fits all” approach to protect human health. These guidelines generally prescribe protective measures (e.g., heat advisories, exposure limits) using models defined by the assessment of heat strain in young and or relatively healthy adults. They fail to consider key factors such as sex, age, health status, and other factors, which can markedly alter a person’s tolerance to heat, thereby leaving a large segment of the population under-protected…(1)

  2. Work/rest schedules vary depending on the organization or governing body that developed them. For example, OSHA & the US Army use a similar work/rest schedule, while the EPA & ISO standards have slightly different recommendations. That being said, it’s important to understand how these recommendations vary, but more importantly, what factors they consider in giving the work/rest schedules (e.g., wet bulb globe temperature-WBGT, temperature, humidity, clothing, sun exposure, wind speed, etc).
  3. One of the biggest problems with work/rest schedules (especially those using WBGT), is that they severely underestimate the heat strain experienced by workers when the evaporative capacity (of sweat) is limited—like in very humid environments or under heavy clothing layers— this means that more workers will be susceptible to heat injury & illness when using WBGT-based work/rest schedules under these conditions. (2)

Table of WBGT Categories

Example of U.S. Army work/rest schedules (3)

SO IN ADDITION TO IMPLEMENTING WORK/REST SCHEDULES,

MAKE SURE YOU’RE ALSO DOING THE FOLLOWING 5 THINGS TO PROTECT YOUR WORKERS:

  1. First and foremost, you can get your workers set up with smart PPE, like the Kenzen patch, that will monitor workers’ physiological data real-time and alert you (and the worker) when their core temperature is reaching unsafe levels, so that they can take a break. This is completely individualized, which solves the problem of work/rest schedules not protecting all populations.
  2. During the rest periods, let your workers actually rest. DO NOT assign any other work tasks while they’re resting- your workers need to cool down, and if they continue to work, their core temperature will keep going up. (3)
  3. Keep checking the weather (WBGT, temperature, and humidity) throughout the day— we recommend every 2 hours— and update the work/rest schedules accordingly if the criteria change.
  4. During rest breaks: provide workers with potable water and shade or air conditioning, and allow them to remove any extra clothing that might restricting evaporative heat loss (i.e., that keeps the sweat from evaporating off of their skin). (5)
  5. If you don’t have a way of monitoring each worker’s individual physiology, then make sure you are attentive to each individual and whether they might be presenting any signs or symptoms of heat injury or illness. Let the individual stop working and rest if they need to (even if the working time limit hasn’t yet been reached). (4,5)

    Lastly, remember: these work/rest schedules were created for young, healthy men, so you will need to pay special attention to how older adults, women, and those with diseases are responding to these schedules on a hot day because they might need a completely different program to stay safe in the heat.

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REFERENCES:

  1. Kenny, G.P., Notley, S.R., Flouris, A.D. and Grundstein, A., 2020. Climate Change and Heat Exposure: Impact on Health in Occupational and General Populations. In Exertional Heat Illness (pp. 225-261). Springer, Cham.
  2. Budd, G.M., 2008. Wet-bulb globe temperature (WBGT)—its history and its limitations. Journal of Science and Medicine in Sport11(1), pp.20-32.
  3. Regulation, T.R.A.D.O.C., 2016. 350-29. Prevention of heat and cold casualties. Fort Eustis, VA: US Army Training and Doctrine Command, Publication TRADOC Regulation, pp.350-29.
  4. Coco, A., Jacklitsch, B., Williams, J., Kim, J.H., Musolin, K. and Turner, N., 2016. Criteria for a recommended standard: occupational exposure to heat and hot environments. control Ccfd, editor.
  5. https://www.osha.gov/heat/
DOES POURING WATER ON YOUR HEAD ACTUALLY COOL YOU DOWN?

DOES POURING WATER ON YOUR HEAD ACTUALLY COOL YOU DOWN?

We’ve probably all been there: sweating it out in the heat, wishing we were in a cool lake or pool, and so we reach for that water bottle and pour the water on our head for some relief.

But does this actually cool you off or is this relief just temporary?

underwater

The answer: it depends on your conditions.

In a hot-dry environment (low humidity):

  • Pouring water over your head can cool you off and lower your core body temperature, but the caveat to this is that you have to be in a place where the water you poured on your body can evaporate off of your skin and get rid of heat (remember, only sweat that evaporates off of your skin actually cools you off).
  • A good breeze is also important to help wick the water off of your skin to cool you down.
    And as you’ve probably guessed, you’d also need to be wearing minimal clothing— like shorts & a t-shirt— as heavy clothing, like PPE, would just trap the water you poured on your body.

strong>In a hot-wet environment (high humidity):

  • If your sweat is already dripping off of you and it’s really humid outside then pouring water over your head might make you feel better, but won’t help you cool down.
  • Research has shown that pouring water over your head can make you feel cooler by reducing your skin temperatures and also reduce your perceived exertion (how hard you feel like you’re working) in the heat. However, it won’t improve your performance.

So, what’s the verdict on pouring water over your head?

Unless you’re wearing light clothing and working in a hot-dry environment where the water can evaporate off of your skin, it won’t help to cool you off. That being said, if it makes you feel better to pour cold water over your head and helps you get through the work day, it won’t hurt you, so go for it- just remember to keep an eye on the signs & symptoms of heat illness.

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REFERENCES:
Munoz, C. X., et al. “Effects of oral rehydration and external cooling on physiology, perception, and performance in hot, dry climates.” Scandinavian journal of medicine & science in sports 22.6 (2012): e115-e124.
Morris, Nathan B., and Ollie Jay. “To drink or to pour: How should athletes use water to cool themselves?.” (2016): 191-194.

WHAT IS YOUR SWEAT RATE & WHY DOES IT MATTER?

WHAT IS YOUR SWEAT RATE & WHY DOES IT MATTER?

Calculating your sweat rate is the best way to figure out how much water you need to be drinking when working or exercising in the heat.

You can use our sweat rate calculator (see below) to figure out your average sweat rate, and how much water you should drink back after your exercise bout or work day.

WHAT YOU NEED TO DO TO GET AN ACCURATE SWEAT RATE CALCULATION:

  1. Pick an activity (ideally during your typical workday) that is 30-60 minutes long, where you are usually sweating. Note that you will need to weigh yourself (nude) before and after the activity, so if this is not possible at work, then go for a run at home or the gym, or do some sort of aerobic (endurance) activity that gets your heart rate up & causes you to sweat (e.g., elliptical, cycling, etc).
  2. Weigh yourself (nude) before exercise and/or work. Write down this number. Go do your activity – and be sure to keep track of the time (be as precise as possible). Note: During this exercise period, you should not use the restroom or drink any fluids. Immediately after you’re done, take your clothes off & wipe off any dripping sweat from your body.
  3. Weigh yourself (nude) again. Write down this number. Enter your two body weights & your exercise/work duration in the calculator below to get your sweat rate & how much water you should drink back!

Sweat Rate Calculator

 

Note that the amount of water to drink back is the amount specific to the activity you did (and that amount of time). If it’s really hot outside, your sweat rate might be even higher, and then you’ll need to drink even more water.

**Remember that you can’t just chug all of that water at once because your body can only absorb it so fast.. as a general rule of thumb, your body can only absorb ~1 cup (8 oz.) of water every 15 minutes, so try to divide up your fluids (over the hour) based on that rule.

For more information, check out our blog on staying hydrated during the workday.

THIS IS A GOOD PLACE TO START, BUT FOR MORE CUSTOMIZED HYDRATION PLANS & RECOMMENDATIONS SPECIFIC TO YOUR SITE, WORK ACTIVITIES, AND CLOTHING, CHECK OUT KENZEN’S HEAT SAFETY PROGRAM– WE’RE HERE TO HELP.