Researchers at San Diego State University (SDSU) are using wearable technology to better understand how extreme heat affects farmworkers in California’s Imperial Valley. Farm work is one of the most physically demanding jobs in the United States, and in this region, summer temperatures frequently exceed 110°F. These conditions create hazardous environments for workers who help sustain one of the nation’s most productive agricultural areas. SDSU’s study combines wearable physiological monitoring with environmental data to capture a detailed, real-world view of heat exposure and worker strain, offering insights that could help improve worker safety practices.
The Imperial Valley is one of the hottest agricultural regions in the country. According to state and federal data cited by SDSU researchers, the area experiences many days each year above 95°F, with peak summer temperatures often surpassing 110°F. These extreme conditions coincide with physically demanding labor, increasing the likelihood of heat-related illness. Workers in this region frequently perform repetitive tasks such as harvesting, bending, lifting, and maintaining irrigation systems, often under direct sun and without much shade. While researchers have long recognized that heat exposure varies based on crop type, field location, and season, there has historically been limited data showing how these differences affect workers’ bodies during their shifts.
Measuring Heat and Worker Physiology
To fill this gap, SDSU collected physiological and environmental data from farmworkers across the Imperial Valley. Some of these workers wore SlateSafety BAND V2 physiological monitors that measured core body temperature and heart rate while performing their daily tasks. At the same time, environmental monitors were placed throughout fields to track temperature, humidity, and other conditions. Researchers also combined these measurements with wet-bulb globe temperature data, satellite imagery, and historical records to map areas of elevated heat across the region.
The combination of wearable physiological data and environmental measurements allowed the research team to identify rural heat islands, areas where temperatures were consistently higher than surrounding fields. These heat variations often occurred even within a single field, highlighting the need to understand microclimates rather than relying solely on general weather readings. By capturing how workers’ bodies responded to these localized heat conditions, the study provided a more accurate picture of risk and helped identify areas where interventions may be most critical.
Insights into Daily Work and Heat Exposure
The study revealed several key patterns regarding heat exposure among farmworkers. Workers laboring in low-lying or ground-level crops were exposed to higher heat levels than those working with taller crops. This is partly due to heat radiating off the soil and being trapped near the ground, where workers spend extended periods bending or kneeling. Exposure levels also varied depending on the season and the type of work being performed, such as preparing fields for planting, maintaining irrigation, or harvesting crops.
Environmental monitoring showed that certain areas within fields consistently experienced higher heat, meaning that a worker’s risk could differ depending on exactly where they were assigned. Additionally, the study found that during extreme heat, insufficient rest breaks increased the risk of heat-related illness. SDSU researchers noted that while California has heat safety rules in place, enforcement is inconsistent, and clear guidance on heat-related rest breaks remains limited. These findings underscore the importance of understanding not just overall climate conditions but also the specific work environment and practices that influence heat risk.
Wearable Technology in Real-World Research
Wearable monitoring was central to the study’s success. SlateSafety devices allowed researchers to continuously collect physiological data directly from workers while they completed their regular tasks. Core body temperature and heart rate data provided a clearer understanding of how heat affects the body under real-world conditions, something that traditional environmental measurements alone cannot capture. By integrating this physiological data with environmental monitoring, SDSU researchers could study the interaction between human bodies and the microclimates of the fields, producing a richer and more actionable understanding of heat exposure.
Using wearable technology in this way demonstrates how modern tools can enhance heat safety research. It allows researchers to move beyond general assumptions about risk and capture detailed, real-time data that reflects the realities of farm work. This approach also supports ongoing efforts to identify the areas and conditions where workers may be most vulnerable to heat stress.
The Importance of This Research
The findings from SDSU’s study provide valuable insights into how extreme heat affects farmworkers in one of the country’s most productive agricultural regions. By combining physiological data from SlateSafety wearables with environmental measurements, researchers were able to identify both the areas of highest risk and the factors that contribute to heat-related strain. This research contributes to a better understanding of rural heat islands and worker safety, offering evidence that could inform policies, guidance, and safety practices in agriculture.
As climate change drives higher temperatures and more extreme weather, studies like this are increasingly important for protecting essential workers. Understanding how and where heat impacts farmworkers is a critical step toward improving safety practices, managing exposure, and supporting worker health. The insights also highlight the potential for wearable technology to play a meaningful role in monitoring and researching occupational heat stress in real-world settings.
Nicolas Lopez-Galvez, assistant professor of public health at SDSU and project leader, emphasized the urgency of the work, in an article by the Associated Press:
“Workers could potentially be dying or having some serious issues. It’s better to start acting sooner.”