The Human and Environmental Physiology Research UNIT

This laboratory houses the world’s only functioning air calorimeter, originally constructed by Dr. Jan Snellen (1925–2000), a physician and researcher at Memorial University in Newfoundland. Relocated to HEPRU in 1998 and extensively re-engineered between 1999 and 2001 by Dr. Kenny and his team, the calorimeter now stands as the gold-standard instrument for assessing whole-body heat exchange in humans.

The calorimeter is situated within a 240-square-foot environmental chamber designed and built by Cantrol International that allows research to be conducted across a wide range of ambient conditions (from -20°C to +50°C and 15% to 85% relative humidity) and air flow settings. The chamber is fully equipped with high-precision monitoring systems that enable the simultaneous measurement of multiple physiological parameters, supporting research both inside and outside of the calorimeter. 

This advanced technology offers an exceptionally precise method for quantifying the heat dissipated by the human body. Among its key advantages are its rapid response time—particularly for evaporative heat loss measurements—low thermal inertia, and high precision even at elevated metabolic rates. The re-engineered Snellen air calorimeter achieves unparalleled accuracy, capable of measuring total heat loss within approximately 2 Watts. When combined with indirect calorimetry to assess energy expenditure, the system enables precise quantification of changes in body heat content.

By integrating these measurements with core, skin, and muscle temperature data, research conducted with the Snellen calorimeter has provided valuable insights into the mechanisms of human thermoregulation under a wide variety of environmental and physiological conditions. Since its commissioning, more than 150 studies examining human heat balance and temperature regulation have been performed using this unique system.

Adjacent to the main chamber is a smaller 80-square-foot chamber used for exercise training and heat adaptation studies. Surrounding these facilities is a spacious work area equipped with advanced monitoring stations and research equipment to support ongoing investigations.

To support the leading-edge research conducted at HEPRU—encompassing studies on participants ranging from young to older adults, both with and without chronic disease—the facility includes a fully equipped patient screening and assessment area.

The front section of the room features a body densitometry unit, weighing scale, blood pressure monitoring system, and other essential instruments that enable a comprehensive, ethically guided, multi-stage health evaluation process. This includes self-administered questionnaires on health history, lifestyle, and physical activity to help identify potential health issues or risk factors, ensuring both participant safety and the scientific validity of each study.

After completing baseline measurements—such as vital signs (resting heart rate and blood pressure) and physical parameters (height, mass, and body composition)—participants move to the rear section of the room to complete an exercise stress test. This assessment helps evaluate physical fitness and detect potential cardiovascular issues such as coronary artery disease.

The testing area is equipped with a medical-grade treadmill (electrically driven with adjustable speed, incline, and safety rails) and a semi-recumbent cycle ergometer (with adjustable seat height and resistance). Used in combination with a metabolic cart, these tools allow for precise measurement of aerobic capacity through cardiopulmonary exercise testing (CPET). The area is also outfitted with a 12-lead ECG and telemetry system for continuous, real-time monitoring of cardiac electrical activity, which can be observed remotely by the team’s physician or clinical exercise physiologist to ensure participant safety throughout the procedure.

The HEPRU features one of the largest studio apartment–style environmental chambers in the world, custom-designed and built by Cantrol International. This self-contained living space includes a main room that combines areas for living, sleeping, and dining, with an integrated kitchen, as well as a separate attached bathroom. The chamber is fully equipped with all essential amenities required for participants taking part in extended research trials lasting from a single day to multiple days.

While it provides the same high-precision control of ambient temperature and humidity as traditional environmental chambers, this innovative facility also allows researchers to modulate air flow and sound to simulate a variety of indoor and outdoor environments. It includes controlled settings for conducting physiological assessments during sleep and is outfitted with a specialized lighting system capable of replicating the intensity and spectral characteristics of natural sunlight within a laboratory setting. As with all HEPRU chambers, this unit can be easily reconfigured to support a wide range of research protocols and experimental designs.

The chamber is equipped with advanced physiological monitoring systems that enable detailed assessments of cognitive and brain function, brain and muscle oxygenation, cardiovascular responses, body temperature regulation, postural stability, and more. Participants are continuously monitored from an adjacent antechamber, which houses multiple physiological measurement systems and large display screens that provide real-time tracking of participant activity and physiological data.

See more about our Studio Apartment Environmental Chamber by clicking here.

The HEPRU Biochemistry and Molecular Laboratory is fully equipped to explore the cellular and molecular mechanisms that underpin human resilience to environmental stressors such as heat, cold, and hypoxia. Utilizing cutting-edge biochemical analysis technologies, the laboratory conducts detailed assessments of cellular responses at both the transcriptional and translational levels through advanced techniques including Western blotting, ELISA, and qRT-PCR.

At the forefront of molecular physiology research, the facility supports comprehensive in vivo and in vitro investigations of complex biological processes such as autophagy, apoptosis, inflammation, and heat shock protein expression. These capabilities enable innovative, multi-level analyses that bridge molecular findings to whole-body physiological outcomes.

This specialized facility is dedicated to investigating the mechanisms and regulatory controllers underlying the body’s heat loss responses—specifically sweating and skin vasodilation—and their essential roles in maintaining internal temperature under various stimuli such as exercise, passive heating, and pharmacological interventions.

The laboratory is equipped with multiple laser-Doppler perfusion and imaging systems that provide real-time, reliable, and accurate measurements of blood perfusion. It also features an advanced array of ventilated sweat capsules for continuous local sweat rate and dynamic measurements, along with equipment enabling intradermal microdialysis to locally administer pharmacological agents. Together, these tools support in-depth exploration of the neural and chemical mechanisms governing dynamic microcirculatory adjustments and sweat gland activation that are critical for sustaining human thermal balance.

To assess heat loss responses under passive conditions, the laboratory employs a water-perfusion suit that allows precise control of skin temperature to induce measurable heat or cold stress within a controlled environment. Additionally, a semi-recumbent cycle ergometer is used to examine thermoregulatory responses during exercise-induced heat stress.

This research space functions as a centralized processing hub for diverse data streams generated from our data-intensive projects. These include raw physiological data (e.g., body temperature), cardiovascular function metrics (e.g., heart rate, blood flow, blood pressure, ECG), subjective measures (e.g., thermal sensation and comfort ratings), environmental parameters (e.g., air temperature, relative humidity, wind speed), and cognitive data (e.g., reaction times, survey responses, EEG). All collected data are systematically processed, refined, modelled, and prepared for scientific analysis using customized analytical platforms.

Additionally, the facility supports advanced modelling of thermoregulatory responses using sophisticated mathematical and computational frameworks. These models simulate the body’s physiological reactions to varying environmental and physical activity conditions, enabling predictions of core and skin temperatures, sweat rates, and cardiovascular adaptations.

The space is also adaptable for research projects that do not require an environmental chamber to control ambient conditions. It is equipped with exercise apparatus and advanced physiological monitoring systems readily accessible from an adjacent storage area.