In the demanding environments of industrial workspaces, heat stress emerges as a formidable adversary against worker safety and productivity. Heat stress, exacerbated by high temperatures and humidity, can severely impair the human body’s ability to regulate temperature, leading to dangerous health conditions such as heat exhaustion and heat stroke. And unfortunately, this challenge to employees and employers alike is only expected to become a greater challenge in the years to come.
Worker Productivity
Should a worksite stay open during a day’s heat wave if the labor productivity for that day is at 50%?
These kinds of questions are becoming increasingly relevant, particularly as the number of heat waves is expected to continue to rise, globally. The consequences of heat stress on worker productivity are stark, with studies indicating a significant reduction in cognitive and physical capabilities as temperatures rise. According to research published in the Journal of the American College of Nutrition, dehydration associated with heat stress can adversely affect worker productivity, safety and morale, emphasizing the importance of frequent fluid replacement in warm environments.
This productivity loss is not just a matter of decreased output; it represents a tangible impact on the bottom line. Some estimates put the loss of productivity due to hot humid days at 650 billion lost labor hours in 2017, having risen by 9% over the last few decades. Some estimates for 2030 suggest heat stress may result in productivity losses amounting to nearly 2% of total working hours in some regions, a figure that translates into roughly $4 trillion in losses globally.
Read more: How Contractors can Beat the Summer Heat
Worker Safety
From a safety perspective, the stakes are even higher. The Occupational Safety and Health Administration (OSHA) and the American Conference of Governmental Industrial Hygienists (ACGIH) recommend replacing fluids frequently when exposed to heat stress, underscoring the critical role of hydration in maintaining a safe work environment.
The risks associated with inadequate hydration and heat stress are profound, with the Centers for Disease Control and Prevention (CDC) reporting over 700 heat-related deaths in a 14-year period, highlighting the dire consequences of failing to manage hydration and heat stress effectively.
Top-down Approaches
The White House has taken steps to address the issue of heat stress and hydration in the workplace through directives focused on increased diligence by OSHA. Recognizing the growing threat of extreme heat exacerbated by climate change, the administration launched a coordinated interagency effort aimed at protecting workers, especially those in outdoor and indoor environments without climate control, who are at high risk of heat-induced illnesses.
One of the key initiatives includes the Department of Labor’s move to start the rulemaking process for developing a workplace heat standard. This effort is aimed at establishing a federal standard to ensure protections for workers exposed to heat in various work settings. The Advance Notice of Proposed Rulemaking (ANPRM) for Heat Injury and Illness Prevention in Outdoor and Indoor Work Settings marks a significant step towards this goal, allowing OSHA to gather input on heat stress thresholds, acclimatization planning and exposure monitoring.
In addition to rulemaking, OSHA has initiated an enforcement initiative focusing on heat-related hazards, prioritizing interventions and workplace inspections on days when the heat index exceeds 80°F. This initiative is part of a broader commitment to workplace safety, climate resilience and environmental justice, addressing the disproportionate exposure to hazardous heat levels faced by workers of color in essential jobs. These actions demonstrate a comprehensive approach to tackling the challenges posed by extreme heat in the workplace, emphasizing the critical importance of hydration and heat stress mitigation to ensure worker safety and productivity.
Read more: 10 Key Elements for a Workplace Heat Safety Program
Bottom-up Approaches
As we delve deeper into the challenges posed by heat stress in the workplace, it becomes evident that a multifaceted approach, including employer and employee responsibilities, is essential for safeguarding worker health and ensuring operational efficiency. Among the myriad factors contributing to heat stress, inadequate hydration stands out as a pivotal element that can exacerbate or mitigate the risks associated with thermal environments.
Studies have routinely shown that most workers show up to work dehydrated and end shifts in a much more dehydrated condition than when they start. Why might this be a problem for heat stress? As dehydration ensues, blood volume decreases, resulting in hypovolemia. This change causes cardiovascular strain and results in the typical symptoms associated with dehydration and heat stress, such as fatigue, loss of mental clarity, headaches, muscle weakness, and so forth.
Rest is also critical when core body temperature gets too high. The combination of high metabolic demands, coupled with dehydration, leaves the heart beating faster to account for the lower blood volume, which in turn prevents larger blood flow for each heart stroke. Without rest and rehydration, the body cannot easily recuperate to allow for proper blood flow to cool down the body and deliver oxygen at the levels demanded, leading to lower physical output and productivity. In a study conducted by Georgia Tech in conjunction with the U.S. military, researchers monitored a metric for heat stress known as compensatory reserve measure (CRM) before and after exercise in the heat. As the study indicates, rest helps a person recuperate from heat stress, but rehydration accelerates the return and ultimately helps bring the individual’s cardiovascular status back to its starting point.
Technological approaches are working to measure cardiovascular strain metrics, such as CRM. Although great strides are being made, there is still more work to be done. In academic and controlled settings, use of variable sensor modalities and machine learning approaches to data analysis are proven to give reliable CRM results, but the challenges that remain are use in real-world, “noisy data” conditions and hardware “ruggedization” issues such as miniaturization, power management, and the awkward necessity of wearing a device stuck to your chest.
Other proxies are often currently used such as heart rate or core body temperature. There are a variety of these tools on the market, usually as wearables on the wrist or chest. While useful, these proxies to cardiovascular strain still come up short, and caution should be applied when relying upon them.
First, individual variation to heat, due to differences in hydration status, heat acclimation, fitness level, and other factors, lead to variability in heat tolerance. Using single number proxies for monitoring employees for heat stress thus leads to loss of productivity for a wide range of employees that can handle the heat and work demands without an issue, while leaving another cohort of employees at high risk of heat related injuries. Second, the continued persistence of heat related injuries in the workplace, and rising environmental stressors, continue to show that current methods are either insufficient to address the complete problem and/or too burdensome in other ways as to be appropriately utilized by workers or employers.
While technology advances, other approaches should still be pursued to lower risk and improve productivity. Company plans for heat stress should be in place with policies that follow standard guidelines for various industries, often related to access to fluids, proper rest, proper cooling opportunities, and education for employees about heat stress and monitoring solutions. In one simple example, OSHA provides a urine color chart as a resource to help provide a simple reminder for employees to self-monitor their hydration status. Self-empowerment is a powerful psychological approach taken in other demanding environments such as elite sports and the military, as well as in a variety of general population healthcare applications and will likely improve results in the workplace, too.
Final Thoughts
It’s important to look for new technologies that help combat current challenges related to heat stress in the workplace. Technology changes quickly, and these new products and services can significantly improve current practices. But it’s also important to know their limitations and not come to rely upon them in situations outside of their scope and capabilities. When the stakes are high, such as heat-related injuries that at times can even result in the loss of life, all opportunities should be explored. But ensuring these tools are only used to assist vigilance in a multifactored approach to safety monitoring is important as we tackle the challenges of today and tomorrow.