As one might imagine, extreme heat can lead to an increase in workplace injuries. According to a recent study by researchers at the University of California, Los Angeles, hot days do not just mean more cases of heat exertion and stroke. Heat stress on the body also leads to a greater incidence of falls and vehicle or machinery mishandling due to loss of concentration. These incidents lead to an additional 20,000 workplace injuries each year in California alone.
On days when the temperature was 85 to 90 degrees Fahrenheit, the researchers found the overall risk of workplace injuries was 5% to 7% higher on days when temperatures were in the 60s. When temperatures reached 100 degrees, the overall risk of injuries was 10% to 15% higher.
In general, heat-related injuries occur in just about every major group of workers across industries that the U.S. Bureau of Labor Statistics tracks. In 2018, 3,120 workers missed at least one day of work due to environmental heat, and more than 1,100 of those workers were in the construction and transportation industries. According to OSHA’s occupational injury cost estimator, using an average 6% profit margin for construction, the direct and indirect costs of a single heat-related incident require about $1.3 million in sales to offset.
According to the National Oceanic and Atmospheric Administration (NOAA), 2020 was the second-warmest year on record—just 0.04 degrees Fahrenheit cooler than 2016. In addition, the world’s seven-warmest years have all occurred since 2014, and 10 of the warmest years have occurred since 2005. As extreme heat becomes more common, organizations around the world must ensure they are taking proactive measures to protect workers.
How Heat Stress Happens
As a person’s core body temperature rises, sweating is the primary natural mode of cooling down. Blood flow increases to the skin, water and electrolytes are expelled by the sweat glands, and evaporation of sweat cools the body. This process is efficient as long as evaporation can occur, activity level does not increase, and hydration is adequate. However, workers on job sites are subject to their environment and productivity requirements, which may disrupt the body’s cooling process.
The heart rate needs to increase during sweating to pump blood fast enough to get it to the skin to cool off the body. Muscles also require blood to get oxygen and other nutrients for proper function during work. This means the cardiovascular system is strained when working in the heat, sending blood to everywhere it is needed. If a worker is sweating and maintaining a steady workload, eventually they are going to feel the fluid loss from sweating. The sweat loss will result in lower blood volume and pressure.
Working in hot weather impacts the nervous system as well, decreasing a worker’s ability to complete their tasks and affecting their cognitive ability. The nervous system needs to work harder to accomplish the same muscle movement it did when the environment was cooler. This makes work-related tasks harder and cognitive decision-making more difficult.
Adaptation to heat takes time and varies by individual, but the process typically takes two to three weeks when managed properly. Appropriate heat acclimatization is accomplished by increasing one’s core body temperature one degree Celsius for an hour each day. If the job requires workers to wear personal protective equipment (PPE), as most do, they need to slowly add PPE as well, for example, adding 20% each day and working toward full worksite coverage.
Keep in mind that heat-related injuries can also happen in cooler weather, particularly if a worker is over-exerting or dressed too warmly, causing overheating in their microclimate (the temperature between the skin and clothing).
Monitoring Heat Health
Measuring an employee’s heat health is imperative for detecting the onset of heat stress and taking steps to prevent incidents, injuries and even death. The standard method of measuring an employee’s core body temperature, the primary indicator of an issue, has been through gastrointestinal pills. Workers swallow one of these pills and a wearable device tracks their temperature over a set period of time as the pill moves through the body. Thermometers can also be used to get a temperature reading, but they do not scale well in workforces and only capture temperature at one point in time.
As workers go through their day, their physiology changes based on the conditions and their body’s response, so it is most helpful to track individuals’ health through continuous monitoring, such as via wearable devices. This allows the employee, supervisor and company to get real-time data that prompts an intervention to restore optimal body temperature and allow return to work, increasing productivity and safety.
Some organizations have started using smart PPE technology to enhance safety and minimize risk. Workers don devices with sensors that monitor heart rate, temperature and sweat rate. These are tracked against the individual’s heat susceptibility, as determined by factors including gender, age, underlying health conditions, current medications, and ability to acclimate. Some devices can send alerts to workers to warn them of stresses to their body, and send these alerts to their supervisors and company. Supervisors can then call a time out for individual workers to restore their bodies to safe working levels, while companies can track health data in various conditions at worksites and across multiple teams for a holistic view of their workforce’s health. Because core body temperature affects the work, this technology can also track productivity at the individual, team and corporate levels.
Preventing Heat Risk for Workers
There are a number of ways to protect workers from the impact of heat. Encourage workers to use a buddy system while on the job. Buddies are responsible for checking on specific coworkers’ well-being and they should talk to each other several times during the work day. If one person notices something strange or out of character with the other, they should alert supervisors and immediately get the person to an emergency cooling station on-site.
Educate workers on the signs and symptoms of heat stress. Encourage them to pay attention to their own symptoms and what their body may be telling them. Let employees know it is dangerous to “push through” the situation by being “tough” under extreme circumstances. It is not productive for the job—heat stress actually slows the work pace and increases errors. Working safely is the goal, not speed or testing the limits of the human body.
Acknowledge when a worker is vocal about symptoms and take all comments about changes in the body seriously. When the onset of heat stress is detected, stop the individual from working, get them to shade or air conditioning, and encourage them to drink fluids, especially water. Check on the person every five minutes to make sure they are recovering and feeling better. After 10 to 15 minutes, they may return to work if their symptoms have subsided. If not, continue treatment to eliminate the symptoms or seek professional medical attention for the worker if symptoms do not subside.
If the worker exhibits symptoms of heat stroke (when their body temperature reaches 104 degrees Fahrenheit and they are confused or vomiting), immediately call for emergency medical services. While waiting for emergency assistance to arrive, help the worker cool down as quickly as possible. If available, try using ice baths or rotating cold compresses around the person’s body. Most importantly, do not leave their side until help arrives.
Heat-related injuries are almost entirely preventable. The latest techniques and tools, such as wearable devices, can help organizations understand the potential severity of the problem and respond appropriately, better protecting employees in extreme working conditions.