Summary:
UCLA researchers in the Department of Medicine have developed a novel geometric model for the determination of the time constant in variable oxygen uptake kinetic systems.
Background:
The kinetic response of oxygen uptake adjustment to moderate-intensity exercise is a main factor of the aerobic function. Aerobic function is an indicator of physical fitness, differing in healthy individuals, and those with various cardiovascular diseases. Typical kinetic response to a change in power can be modeled as an exponential function with a time constant (τVO2). Although critical to oxygen uptake modeling, τVO2 is difficult to measure due to the variability of breath-by-breath uptake values and breath interval variability. Overcoming the oxygen uptake variability is a matter of physical repetition and the superimposition of the measured breath-by-breath data; typically six exercise repetitions are implemented for power output tests. Current testing protocols are time consuming and burdensome to subjects in clinical studies, and thus there is a need for a novel method to efficiently determine the time constant.
Innovation:
UCLA researchers have developed a novel mathematical method for the determination of τVO2, a vital component of aerobic fitness useful in assessing the efficiency of a person’s oxygen use. This model requires only a single exercise protocol while maintaining an accuracy equivalent to or better than the current gold-standard methods reliant on multi-point studies. The time saved from not having to perform multiple exercises can be reinvested in extending the single protocol, enabling measurement of the τVO2 for the on-transit and off-transit as well and giving clinicians and researchers a more complete picture of the target’s aerobic fitness. As the proposed technology is a computational model, integrating it into an already existing in vivo exercise study is simple. This novel method has potential in a wide array of applications, including the design of customized rehab programs, developed by the understanding of individual oxygen uptake kinetics. Such advances can allow therapists and athletic trainers to monitor and adjust programs as needed.
Potential Applications:
• Disease progression monitoring/clinical research
• Measuring effectiveness of therapeutic interventions.
• Rehabilitation and physical therapy
• Athletic performance monitoring
• Development optimization of personalized fitness programs
Advantages:
• High precision: highly accurate measurements of oxygen uptake kinetics, within a range of 1.5 to 3.5 seconds.
• Single exercise protocols
• Time-efficient
• Low variability
• Broad applicability
• Versatility: may be applicable to data obtained from a metabolic measurement system with a mixing chamber, which could further increase the precision of the readings.
State of Development:
The inventors have developed this model and published a research article in a physiology journal. The model has been tested and verified against 3,600 generated breath-by-breath series with applied random variation, encompassing the physiological behaviors of healthy patients and patients with cardiovascular diseases.
Related Papers:
Cooper, Christopher B., and Alan Garfinkel. "A novel geometric method for determining the time constant for oxygen uptake kinetics." Journal of Applied Physiology 133.5 (2022): 1081-1092.
Reference:
UCLA Case No. 2022-253
Lead Inventor:
Christopher B. Cooper, UCLA Professor Emeritus of Medicine and Physiology