PPG Exercise Intensity via Heart Rate Error Correction
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Solution Overview
Problem
Photoplethysmogram (PPG) sensors face accuracy issues in determining exercise intensity due to the 'white knuckle' effect, which occurs when muscle contraction affects blood flow, leading to noise artifacts and inaccurate heart rate measurements, especially during weight training and cardiovascular exercises.
Innovation Solution
A wearable device that combines a PPG sensor with a processor circuit to measure heart rate and motion data, using experimental data from both ECG and PPG sensors to calculate exercise intensity by analyzing heart rate errors and body movements, and providing coaching based on user-specific factors like age, gender, and experience level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If PPG sensor is used to measure heart rate during exercise, then the device complexity is reduced and ease of operation is improved, but measurement precision deteriorates due to the white knuckle effect causing noise artifacts
Solution Approach 1:
The patent uses ECG sensor data as an intermediary reference to correct PPG measurement errors. The ECG provides a reliable reference heart rate signal that mediates the correction of PPG artifacts caused by the white knuckle effect, allowing the system to maintain ease of wrist-based operation while improving measurement precision through computational correction.
Solution Approach 2:
The system changes the parameter being measured from direct PPG heart rate to corrected heart rate derived by comparing PPG with ECG reference data. By transforming the measurement parameter through error calculation and correction algorithms, the system overcomes the limitations of PPG during muscle contraction while maintaining the ease of optical sensing.
2Measurement precision
If ECG sensor is used to measure heart rate, then measurement precision is improved, but device complexity increases and ease of operation deteriorates due to chest strap requirement
Solution Approach 1:
The patent merges ECG and PPG sensing capabilities into a single integrated system. The wearable device incorporates both ECG electrodes and PPG optical sensors, allowing the device to function as a chest strap during high-intensity exercise (using ECG) and as a wrist device during low-intensity exercise (using PPG), thus combining the advantages of both approaches.
Solution Approach 2:
The system dynamically switches between ECG and PPG measurement modes based on exercise intensity detection. During low-intensity exercise, it uses the simpler PPG mode for ease of operation. During high-intensity exercise where white knuckle effect occurs, it automatically transitions to ECG mode to maintain measurement precision, making the overall system adaptable to different operational conditions.
3Productivity
If PPG sensor is used during high intensity exercise, then productivity is maintained, but measurement precision deteriorates due to increased white knuckle effect
Solution Approach 1:
The system implements feedback by continuously monitoring exercise intensity and comparing PPG-derived heart rate with expected heart rate based on exercise intensity. When discrepancies indicate white knuckle effect interference, the system provides feedback to switch measurement modes or apply correction algorithms, ensuring accurate intensity monitoring throughout the workout without interrupting exercise productivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Improves the accuracy of exercise intensity measurement by correlating heart rate errors with intensity levels, offering personalized coaching to optimize workout efficiency and effectiveness.
Implementation Method 1
PPG sensors use an optical technology to measure the rate of blood flow and derive the heart rate
Implementation Method 2
ECG sensors use electrical activity of a heart to measure the heart rate
Data Source
AI summary
Disclosed systems and methods relate to determining an intensity level of an exercise using a photoplethysmogram (PPG) sensor. A method of determining an intensity level of an exercise for a user according to one embodiment of the present disclosure includes detecting, by a device, body signals from the user using a PPG sensor. The method includes determining, by the device, a heart rate of the user based on the body signals. The method includes determining, by the device, an error in the heart rate. The method also includes determining, by the device, the intensity level of the exercise for the user based at least on the error.