Georgia Tech researchers tested the reSPIRE platform in 18 healthy adults, demonstrating accurate tidal-volume estimates and synchronized monitoring during loaded breathing and stationary cycling.
A chest-worn sensor developed at the Georgia Institute of Technology can estimate how much air a person breathes while simultaneously tracking respiratory-muscle activity and cardiovascular response, an early step toward wearables that explain breathing effort rather than merely count breaths.
The reSPIRE platform was tested in 18 healthy young adults during controlled breathing, resistance-loaded respiratory maneuvers and stationary cycling. Results from the study published in Biosensors and Bioelectronics showed that the device estimated tidal volume—the amount of air moved during a breath—with a coefficient of determination of 0.91 under controlled conditions.
John Berkebile, H. Trask Crane, Kevin Swamy, Farhan Rahman and Omer Inan of Georgia Tech developed the system with Jesús Antonio Sánchez-Pérez of the University of Puerto Rico at Mayagüez. The paper appeared online February 10 and in the journal’s June 1 issue.
The team designed reSPIRE around a limitation of many respiratory wearables: breathing rate alone cannot show how much air is moving or how hard the respiratory muscles must work to move it. A person breathing faster during exercise may be ventilating efficiently, struggling against an added load or recruiting additional muscles to compensate. Those states can produce a similar rate but represent different physiological demands.
Positioned over the sternum, reSPIRE combines several measurement methods. Impedance pneumography estimates ventilation from changes in electrical impedance across the chest. Surface electromyography and mechanomyography capture electrical and mechanical activity from respiratory muscles. Electrocardiography records the heart’s electrical activity, while optical, mechanical and impedance signals provide information about cardiovascular dynamics.
The advantage is synchronization. Muscle recruitment, ventilation and cardiovascular response are recorded on the same platform and timeline, allowing researchers to examine how the systems change together rather than reconstructing the relationship from separate instruments.
Participants first completed periods of spontaneous breathing and deliberately changed their breathing rate and depth. They then breathed against progressively greater inspiratory and expiratory resistance before completing a stationary-cycling protocol followed by recovery.
Wearable measures associated with respiratory-muscle force correlated strongly with inspiratory mouth pressure, a reference measurement taken while participants inhaled against resistance. The reported Spearman correlation was 0.87. Muscle-signal patterns also changed significantly across inspiratory and expiratory loads.
During cycling and recovery, the system continuously followed changes in ventilation, heart rate, pre-ejection period and impedance-cardiography amplitude. Those results demonstrate that the individual sensors can operate together during structured exercise, although the experiment did not test unrestricted daily movement.
That distinction is important. A recent review of wearable respiratory monitoring during motion identifies movement artifacts, postural changes, electrode drift and variable breathing patterns as continuing barriers to reliable assessment outside controlled settings. Coughing, perspiration, different body shapes and long-term skin contact could introduce challenges that were not captured in the reSPIRE experiment.
The study also involved only 18 healthy adults without cardiopulmonary disease. It did not test whether the system can diagnose illness, detect deterioration, guide rehabilitation or improve treatment. According to the paper’s disclosure, Inan is a co-founder with a financial interest in Cardiosense, a company developing technology related to wearable monitoring, and serves as chief scientific officer of Biozen.
The path from engineering performance to medical usefulness requires more than accurate laboratory measurements. A widely used digital-health evaluation framework published in npj Digital Medicine distinguishes technical validation from validation in the intended clinical population and evidence that a tool works within an actual healthcare system.
Those are now the tests facing reSPIRE. Researchers will need to examine longer wear periods, comfort, durability and signal stability during ordinary movement, then determine how the system performs in people with abnormal breathing.
The prototype’s immediate advance is integration. It demonstrates that a wearable can capture several dimensions of cardiopulmonary effort at the same time without requiring a collection of independently synchronized laboratory instruments. Its clinical value will depend on whether that richer view detects a meaningful change sooner—or explains it more clearly—than simpler monitoring.
