Dripping beads of sweat and getting a sunburn aren’t the only signs you’ve been spending too much time in the sun. New research shows the effects of heat and humidity are more far-reaching and affect more body systems than we realized. And with temperatures around the globe continuing to rise, these effects will be felt by more workers soon. Beyond the obvious signs, how exactly do our bodies react to the heat and what does that mean for worker safety?


Reduced cognitive function

Research shows that warmer weather and dehydration can impede our ability to make complex decisions and may cause people to shy away from considering these decisions at all. That’s because the body has to work harder and use more energy to keep a stable and normal internal temperature in hot and humid environments. These body regulations can reduce cognitive abilities and may make people use overly simplified decision-making processes even if they lead to less optimal results.

This can be true when making decisions over a longer period of time, as well. A small study of college students showed that students living in buildings without air conditioning had a 13% longer reaction time during cognitive tests when compared to students who lived in buildings with air conditioning. In addition, students living in air-conditioned buildings gave more accurate responses than students who didn’t live in air-conditioned buildings. Other studies have found hot weather can reduce scores on standardized tests and create a greater risk of judgment errors. Results showed that taking an exam when the temperature is 90⁰ Fahrenheit reduced performance by around 14 percent compared to results on exams taken on a 72⁰ Fahrenheit day. We can apply all of this to industrial safety where the stakes are much higher as we imagine an overheated and impaired worker trying to remember to follow their confined spaces checklist or mention a risk they saw to the safety manager, which can become life or death decisions.


Increased emergency room visits

Workers with medical conditions may be at increased risk in the heat, as well. One study found a positive association between extreme heat exposure in the short-term and an increase in emergency room visits for anxiety and mood disorders as well as substance abuse. This can be due to certain conditions causing underlying deficiencies in regulating heat, medications inhibiting body heat regulatory functions, or more fragile bodies not being able to react well to intense heat. Even common medications for allergies or high blood pressure can make it harder for a workers’ body to regulate temperature and hydration in the heat and lead to emergencies.


Negative effects on sleep

Increased temperatures already cause hundreds of millions of dollars in financial costs, including medical expenses, disability claims, as well as lost wages and productivity. High temperatures currently cause around 15,000 reported injuries in the state of California each year, alone. But hot conditions during the workday aren’t the only factor at play. Higher temperatures at night can create a domino effect that negatively impacts a worker’s daytime performance, too. If temperatures at night are too high, workers won’t be able to get a comfortable, full night’s sleep. Without a good night’s sleep, they feel tired at work, take more breaks, work at a slower pace, make more mistakes, and have a greater chance of suffering an injury.

After spending all day in the heat, it’s crucial that your workers cool down in the evening and overnight. But if there’s an intense heat wave or your workers don’t have air-conditioning at home, they may not be able to cool their core down and will come back to work with an exhausted body that’s less suited to handle the heat. Prolonged heat exposure can be especially deadly for older workers as well as workers with lung or heart problems, too.


Greater likelihood of suffering an injury

Diving deeper, a UCLA study found that more workplace accidents and injuries occur on hot days, regardless of whether or not heat was directly related to the accident or injury. Specifically, when the temperature was over 90⁰ Fahrenheit, workers were 6-9 percent more likely to suffer an injury compared to a day when the temperature was in the 50-60⁰ Fahrenheit range. When the thermometer reached triple digits and above, risk of injury was 10-15 percent more likely.


Increased absenteeism

Sweltering temperatures can become so severe that workers may not want to put their health at risk and come in at all. One survey of garment sewers found that they were 5 percent more likely to stay home on a hot day. Similar results were found for workers who make steel products on highly mechanized shop floors, too. As more geographical areas get hotter and become harder to work in, it makes sense that this trend of higher absenteeism will continue to rise.


How can you protect your workers?

The best way to protect workers is to create a heat safety plan that teaches workers about the dangers of working in the heat, creates emergency protocols if workers succumb to heat illness, and includes general heat illness prevention measures. Even in hot and humid working conditions, you can create and fine-tune a plan for the specifics of your work environment – whether indoors, outdoors, or both.

Heat safety experts recommend eight separate measures to provide an all-encompassing strategy, such as providing workers with:

Icy cold hydration options immediately near their jobsite they can drink before, during, or after their shift

  • Shady and cool areas away from the heat where they can rest and relax
  • Proper body cooling PPE that can help workers stay comfortable in the heat for hours
  • Pre-cooling and post-cooling interventions such as body cooling PPE have been shown to enhance exercise performance by as much as 6 percent. If a top-tier athlete becomes more productive with pre- and post-cooling, imagine how much more productive your workers can be!


Other measures include:

  • Acclimatizing workers to the jobsite’s temperature over the course of 5-7 days so their bodies can develop adaptations to cope with heat stress better.
  • Providing physiological monitors like smartwatches or heart rate trackers so they can track their heart rate or skin temperature
  • Using a wet bulb globe temperature (WBGT) monitor to determine the true temperature of your jobsite to account for natural or manufactured elements

It’s not just about being uncomfortable! The effects of working in hot conditions impact different body systems and workers in ways they may not even realize. Don’t wait until the heat is already here. Start preparing your workers to stay safe now.