Pushing physical limits is part of the daily routine for athletes, public servants, and fitness enthusiasts. They feel strong, look healthy, and have no symptoms of heart trouble. But traditional EKG based cardiac tests often miss the subtle signs of stress in the hearts of highly active, asymptomatic people. The complex machines in hospitals are not designed to track fitness outside of clinical settings.
All above demonstrates the need for a new metric: the Reserve of Relaxation (RoR) of the heart. It’s an effective new way to quantify cardiac health using wearable EKG devices.
What is Reserve of Relaxation (RoR)?
The heartbeat is comprised of contraction (pushing blood out) and relaxation (refilling for the next beat). In medical terms, these two intervals are measured as the QT (contraction) and the RI (relaxation) intervals shown in Figure 1.
Figure 1. Cardiac cycle with QT and RI intervals.
Under physical stress, the heart beats faster and the time to relax gets shorter. If the RI interval becomes too short, the heart doesn't have enough time to recover from the previous beat. This imbalance can lead to an irregular heart rhythm (arrhythmia), which can be dangerous.
It should be noted that RoR calculation requires only two key measurements. The first one is the current value of the relaxation interval (RI, Fig. 1), which can be acquired from a single-lead wearable EKG sensor. The second one is the minimal value of the relaxation interval (RImin), which can be determined from the mathematical model of cardiac electrical excitation. These two values outline a measure of RoR that tells one how much "reserve" is left in their heart to handle stress before cardiac excitation gets unstable. This transformative measure is detailed in US Patent No. 10,076,259 and is being brought to the forefront by mutual efforts of the University of North Carolina at Greensboro (UNCG) and Monebo Technologies Inc.
So, how did we measure cardiac fitness before RoR? And why wasn't it good enough for active, healthy people? Previously, doctors relied on methods created for sick patients in a clinic but these had low sensitivity for detecting risk in asymptomatic individuals. For example, a key warning sign in cardiac patients is EKG ST-segment depression which indicates insufficient supply of blood due to damage from a past heart attack. However, clinically significant ST-segment depression needs to be greater than a certain threshold. A fit athlete, even under significant physical stress, does not reach this threshold and, therefore, provides no warning signs of an overperformed heart if assessed only by EKG.
RoR is a different measure. It provides a continuous scale that shows how one’s cardiac relaxation changes under physical stress. Instead of waiting for a clear danger signal, one can assess their cardiac reserve of relaxation before its insufficiency becomes a problem. This information could allow for proactive adjustments of fitness training to individual needs.
RoR in the Real World with Monebo -UNCG
In collaboration with UNCG, Monebo Technologies Inc. is currently integrating this patented RoR technology into products designed for pre-clinical and outpatient settings. Our goal is to move it into the hands of people who need it most.
Strenuous exercise can significantly reduce people’s heart relaxation reserve, putting them at risk without preliminary warning signs. Therefore, RoR technology provides a crucial tool for anyone looking to enhance their physical performance without harm.
Stay tuned for more from the Monebo team.
