Construction can be a hot line of work during the summer months across the nation. But how hot are workers getting, and what are the potential environmental effects on their personal health and wellness?
These are the questions that Kinesiology Associate Professor Zac Schlader and his team at IU Bloomington, the University of New Mexico, and La Isla Network, hope to answer. The pioneering four-year longitudinal data research project will track core temperatures in approximately 300 construction workers employed on large, commercial construction sites based in the southeast. The project is supported by a National Institutes of Health (NIH) four-year grant totaling $4 million, with additional funding for the first year coming from Turner Construction to project partner La Isla Network.
A team effort
Schlader has partnered with CEO of VigiLife and Kelley School of Business graduate Zachary Kiehl to use their real-time worker safety app SafeGuard to collect data from Garmin Instinct smartwatches that track the participant’s heart rate.
“Some of these sites are larger than the IU Bloomington campus and can have more than 6,000 workers on site on any given day,” says Schlader. “The gold standard is a heart rate chest strap, but it is pretty uncomfortable and not something you want to wear every day. We since validated the use of the smartwatch that streams right into the app.”
Schlader says that the partnership with Kiehl has been a game changer, as it has enabled the heat stress research to move out of the lab and into the field. VigiLife utilizes an algorithm developed by the U.S. Army Research Institute of Environmental Medicine to estimate core temperature based on heartrate. The data collection began in March of this year and will continue through September, which is prime “heat season.”
“The only criteria for participants is that they are a construction worker and they don’t work more than 25 percent of their day in air conditioning,” says Schlader. “Our goal is to have at least 80 participants finish per year, as we have to account for real-world factors like reassignments to other sites.”
Effects of extreme heat
Schlader says for all heat illnesses, the key principal signal is hyperthermia, or a dangerous increase in core body temperature. This can affect kidney function, as blood flows away from key areas to help support blood pressure regulation when a person gets too hot. If dehydration is added to the mix, that creates extra work for the kidneys to concentrate urine. For instance, people who suffer from heat stroke often have associated acute kidney injury (AKI).
“A single bout of AKI is strongly associated with chronic kidney disease later in life,” says Schlader. “There is also a risk that workers who are overheating on a daily basis can be at risk for kidney stress that can develop into AKI.”
A new research frontier
Since this study is truly the first of its kind in the United States, Schlader says there is no existing baseline data for how hot workers are getting out in the field throughout the summer. However, initial data shows more cases of hyperthermia than expected.
“Normal core body temperature is around 98.6 degrees Fahrenheit, but we are seeing workers that are measuring more than 101 degrees,” says Schlader. “There is a lot of ways we can leverage this data to help evoke change within the industry, as well as within workers in the United States in general.”
Other topics Schlader and his team hope to explore throughout the course of the study are acclimatization and possible mechanisms that may contribute to an individual’s kidney resilience.
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