Summer Hazards

How Technology Is Transforming Heat Stress Prevention in the Workplace

Traditional heat safety programs often rely on generalized thresholds and reactive symptom reporting. New tools like PPG wearables, WBGT monitoring systems, and cooling innovations are helping safety teams take a more proactive approach.

• By Zack Braun
• Feb 27, 2026

Heat stress and overexertion are critical issues in the workplace, especially when workers wear heavy PPE, are exposed to high ambient temperatures, perform labor-intensive tasks, or work outdoors in summer heat. According to OSHA, heat causes more deaths than any other weather-related hazard in the U.S., and workers in settings without adequate climate controls are at a severe risk of heat illnesses. Regulatory emphasis has been placed on heat hazards as seen in initiatives such as the National Emphasis Program (NEP) and the Heat Injury and Illness Prevention in Outdoor and Indoor Work Settings Rulemaking in recent years.

These programs have urged better data collection, education, and planning on heat safety for workers. Traditional methods used for years are no longer effective —they aren’t holding up. With technology, monitoring heat stress can be easier and significantly more comprehensive. This article will explore how these new technologies are transforming how organizations protect workers from heat strain and how technology can be integrated into heat illness prevention and management plans.

The Challenge with Traditional Methods

Traditional heat stress monitoring programs rely on a combination of environmental measurements, administrative controls, and worker awareness to identify risk. OSHA and NIOSH guidance emphasize evaluating both environmental heat and metabolic heat generated by physical work, noting that heat-related illnesses can occur even in moderate temperatures.

These are the most common approaches:

• Environmental monitoring, most often using the Wet Bulb Globe Temperature (WBGT) to account for air temperature, humidity, radiant heat, and air movement. WBGT reflects ambient conditions rather than individualized physiological responses.
• Workload and PPE assessment, which considers physical exertion levels and the heat-retaining effects of clothing or protective gear (also known as the clothing adjustment factor) that can limit the body’s ability to dissipate heat. Unfortunately, these assessments rely on assumptions and estimates, rather than real-time physiological data, and cannot account for individual differences, environmental changes, or cumulative strain on the worker.
• Administrative controls, including work-rest schedules, hydration practices, shaded or cooled recovery areas, and acclimatization plans to gradually adapt workers to hot conditions. These controls rely heavily on averages and are based solely on averages, whereas in the real world, different workers may need different break times and varying hydration levels.
• Training and symptom recognition, where workers and supervisors are taught to identify early signs of heat-related illness and use observation or buddy systems to intervene when symptoms appear. This approach is individualized but has its own limitations. It is reactive, not preventive — intervention often happens only after symptoms appear, which may already indicate significant heat strain. Additionally, symptoms are subjective, and workers may underreport them or lack a buddy nearby to report on their behalf.

Together, these methods form the backbone of most heat illness prevention and management plans, but they often rely on generalized thresholds, periodic checks, and visible symptoms, creating a one-size-fits-all approach. Since work conditions and individual physiological responses vary significantly throughout a workday, the need for more proactive, individualized tools is clear.

Next, let’s review how physiological monitoring, environmental sensing, and cooling innovations can enhance these traditional methods.

Physiological Monitoring: The New Method

Physiological monitoring is the continuous or intermittent tracking of vital bodily functions, such as heart rate and core body temperature. There are typically two methods for physiological monitoring: electrocardiogram (EKG) or Photoplethysmography (PPG) sensors. In this article, we focus on the PPG sensor, but note that, historically, EKGs have been used for occupational safety, though reliance has been decreasing due to comfort issues.

PPG sensors have emerged as an innovative solution in workplace safety. These sensors measure dynamic changes in blood volume. From there, these sensors can extract heart rate, blood oxygen saturation (SpO2), heart rate variability, core body temperature, and respiratory rate. Typically, PPG Sensors are found in clinical settings as part of patient monitoring systems. One common tool with PPG sensors used in hospitals and doctors’ offices is the Pulse Oximeter. This technology has also been incorporated into everyday wearables and is now in safety wearables as lifesaving equipment.

PPG sensors are often integrated into physiological monitoring systems that workers can wear easily, and supervisors can remotely monitor them via a computer or mobile app. Continuously monitoring how workers are performing and receiving real-time alerts when a worker exceeds a safety threshold are important for a robust heat illness prevention and management plan that accounts for individual differences among workers. 

WBGT Thermometers: A Tried-and-True Method

WBGT monitoring has been a standard method for assessing heat stress for decades. According to the Korey Stringer Institute, the military began to monitor environmental conditions to prevent soldiers from experiencing heat illnesses or death, and ultimately implemented policies that required WBGT as early as the 1940s.

Traditionally, WBGT thermometers combine sensors that measure air temperature, solar radiation, wind, and relative humidity. More specifically, the black bulb on top of many devices is used to account for solar radiation, providing a more complete picture of heat-stress risk in outdoor environments. These instruments must be placed in the work area, ideally at the same location where employees perform their tasks and checked periodically to ensure accurate reading. WBGT readings are then compared to established occupational heat stress guidelines to determine whether work-rest cycles, hydration breaks, or additional safety controls are needed.

In addition to physical thermometers, a variety of digital tools and apps make WBGT data more accessible. For example, NOAA’s and other online platforms provide location-specific WBGT readings and heat indices. These resources allow safety teams and supervisors to plan shifts, breaks, and hydration protocols based on current conditions, making it easier to manage heat stress in their environment.

While WBGT thermometers remain a trusted method for assessing environmental heat, they don’t capture individual responses. Even within safe WBGT ranges, factors such as workload, clothing, and acclimatization can affect heat stress, underscoring the value of complementing WBGT with more individualized, real-time tools.

Cooling Innovations: A Complementary Method

Cooling innovations are increasingly important for managing heat, directly supporting the body’s ability to regulate temperature. These technologies are designed to reduce heat strain at the individual level and are most effective when used alongside traditional controls such as hydration, rest breaks, acclimatization, and environmental monitoring.

• Cooling garments
• Vests, shirts, and wraps are among the most widely used cooling solutions in occupational settings. Many rely on phase change materials (PCM) that absorb heat as they change state, helping keep the torso cooler during work in hot environments or while wearing heavy PPE. Research shows cooling garments can reduce thermal discomfort and perceived heat strain, particularly in PPE-intensive or high-exertion jobs.
• Cooling tools and recovery devices
• Tools such as evaporative cooling towels, forearm or hand cooling devices, and air or liquid cooled systems are often used during rest breaks or recovery periods. NIOSH notes that targeted cooling during breaks can help lower heat strain and support recovery when environmental heat and workload are high.
• Cooling integrated PPE and emerging technologies
• Advances in ventilated PPE, moisture-wicking textiles, and active cooling systems aim to reduce heat retention without compromising protection. These innovations improve comfort and heat dissipation and can enhance existing heat illness prevention strategies when integrated into a broader safety program.

Integrating Technology into Heat Illness Prevention and Management Plans

When used together, physiological monitoring, environmental sensing, and cooling innovations provide a comprehensive approach to preventing heat stress. WBGT monitoring provides important context on environmental conditions. PPG sensors offer real-time insight into how individual workers respond to heat and exertion. Finally, cooling technologies help reduce physiological strain before it escalates. By unifying these tools, safety teams can make earlier, more informed decisions and apply controls such as breaks, hydration and task adjustments more efficiently.

As heat risk continues to rise across industries, relying on a single method is no longer sufficient. By combining proven traditional practices with modern technology, organizations can shift from reactive responses to proactive prevention. A layered heat safety strategy that accounts for environment, workload, and individual responses helps reduce incidents, protect workers, and build more resilient safety programs for the future.

This article originally appeared in the February/March 2026 issue of Occupational Health & Safety.