As temperatures continue to rise across North America, employers are looking for practical ways to identify heat strain before it becomes a serious safety incident.
A newly published study provides encouraging evidence that wearable technology may help.
Researchers evaluated the ECTemp™ algorithm, a validated method for estimating core body temperature from heart rate data, in 102 construction workers during real-world summer work shifts.
The study compared core temperature estimates generated from two heart rate monitoring devices:
- A Polar H10 chest strap
- A Garmin Instinct 2 smartwatch
The key finding: the Garmin smartwatch performed comparably to the chest strap when estimating workers’ core temperatures.
Why Core Temperature Matters
Heat-related illness remains one of the most significant risks facing outdoor and physically demanding industries.
Construction workers are particularly vulnerable. Although they represent only a small percentage of the U.S. workforce, they account for a disproportionate share of occupational heat-related injuries and fatalities.
Core temperature is one of the most important indicators of heat strain. Traditionally, measuring core temperature in field settings has required invasive or impractical approaches, including ingestible temperature sensors.
The ability to estimate core temperature using wearable devices offers a more scalable approach to monitoring worker heat stress.
Inside the Study
The research followed 102 construction workers during summer work shifts in the Midwest United States. Data for the study were collected using VigiLife’s Safeguard™ wearable monitoring platform, which captured the physiological and environmental data used by researchers to evaluate the ECTemp™ algorithm under real-world construction site conditions.
Researchers measured:
- Gastrointestinal temperature using ingestible telemetric pills
- Heart rate using a Polar H10 chest strap
- Heart rate using a Garmin Instinct 2 smartwatch
The heart rate data from both devices were used as inputs into the ECTemp™ algorithm to generate estimated core temperatures.
The goal was to determine whether a commercially available smartwatch could provide estimates comparable to those generated from a traditional chest strap monitor.
What the Researchers Found
Both devices produced similar estimates of core temperature.
When compared against gastrointestinal temperature measurements, the Garmin-based estimates showed slightly lower bias than the chest strap-based estimates.
The study also found strong agreement between:
- Garmin heart rate measurements and Polar heart rate measurements
- Garmin-derived ECTemp estimates and Polar-derived ECTemp estimates
Most importantly, the Garmin smartwatch achieved performance levels consistent with previous ECTemp validation studies conducted in military, athletic, and agricultural settings.
The researchers concluded that both approaches provide adequate estimates of core temperature for monitoring construction workers at the group level.
Why This Matters for Worker Safety
For many organizations, practicality determines whether a safety program succeeds.
Chest straps can provide highly accurate physiological data, but they may be uncomfortable, difficult to deploy at scale, and less likely to be worn consistently throughout a workday.
Smartwatches offer several advantages:
- Familiar form factor
- Easier worker adoption
- Less intrusive wear experience
- Continuous physiological monitoring
- Potential for large-scale deployment
The study’s findings suggest that modern smartwatches can provide meaningful heat strain insights without requiring specialized chest-mounted equipment.
This is an important step toward making physiological heat monitoring more accessible in construction, utilities, manufacturing, energy, mining, transportation, and other high-risk industries.
From Research to Real-World Prevention
While the researchers note that estimated core temperature should be interpreted carefully at the individual level, the technology demonstrated strong potential for monitoring heat strain trends across workforces.
When combined with environmental conditions, workload data, and established prevention strategies such as rest, shade, hydration, and work-rest scheduling, wearable monitoring can help organizations make more informed heat safety decisions.
The future of heat safety will increasingly rely on practical, scalable technologies that fit naturally into workers’ daily routines.
Research like this helps validate that approach.
Strengthening VigiLife’s Scientific Foundation
One of the study’s co-authors, Dr. Erica Tourula, recently joined VigiLife full-time.
Dr. Tourula brings extensive expertise in occupational heat stress research, field-based worker studies, physiological monitoring validation, and translating scientific findings into practical workplace safety programs.
The study also reflects VigiLife’s commitment to evidence-based innovation. By using the Safeguard™ platform to collect field data, the research demonstrates how operational safety technology can also support high-quality occupational health research that advances heat stress prevention across industries.
Her work has focused on understanding how heat affects workers in real-world environments and how emerging technologies can help organizations better protect their people.
As VigiLife continues to advance wearable monitoring and heat safety solutions, research-driven leadership remains central to transforming scientific evidence into actionable worker protection.
Looking Ahead
This study provides further evidence that wearable technologies can play a meaningful role in occupational heat stress management.
Perhaps most notably, it demonstrates that a rugged commercial smartwatch can perform on par with a traditional chest strap when estimating core temperature in construction workers.
As employers face increasing heat-related risks, practical wearable monitoring solutions will continue to become an important component of comprehensive worker safety programs.
Read the full study: Validation of the ECTemp™ algorithm in construction workers: a comparison of photoplethysmography smartwatch and chest strap heart rate monitors.
Citation Maxime Jeanovitch Lignier et al 2026 Environ. Res. Commun. 8 065044
FAQ
Can a smartwatch estimate core body temperature?
Recent research found that a Garmin smartwatch produced core temperature estimates comparable to a traditional chest strap monitor when used with the ECTemp™ algorithm in construction workers.
Why is core temperature important for worker safety?
Core temperature is a key indicator of heat strain and can help identify elevated risk for heat-related illness during physically demanding work.
What industries can benefit from heat stress monitoring?
Construction, utilities, manufacturing, mining, oil and gas, agriculture, transportation, warehousing, and other industries with significant heat exposure can benefit from heat stress monitoring programs.
Are smartwatches as accurate as chest straps for heat monitoring?
This study found that Garmin smartwatch-derived estimates showed similar performance to chest strap-derived estimates for group-level monitoring of construction workers.
Who is Dr. Erica Tourula?
Dr. Erica Tourula is an occupational heat stress researcher whose work focuses on worker safety, physiological monitoring validation, field research, and translating scientific findings into practical workplace heat stress prevention programs. She is now on staff at VigiLife.