Determining heart rate with reflected light data

Abstract

Embodiments provide physiological measurement systems, devices and methods for continuous health and fitness monitoring. A wearable strap may detect reflected light from a user's skin, where data corresponding to the reflected light is used to automatically and continually determine a sequence of instantaneous heart rate of the user. Specifically, the heart rate of the user may be determined through the use of a peak detection algorithm that determines an R-wave-to-R-wave interval (RR interval). Based on the confidence of the RR interval, the peak detection algorithm or a frequency analysis algorithm may process the reflected light data to determine the sequence of instantaneous heart rates of the user.

What is claimed is: 
     
         1 . A wearable physiological measurement system comprising:
 a wearable strap configured to be couplable to an appendage of a user, the wearable strap comprising:
 one or more light emitters for emitting light toward the user's skin, 
 one or more light detectors for receiving light reflected from the user's skin, and 
 an electronic circuit board comprising a processing module configured for analyzing data corresponding to the reflected light to automatically and continually determine a sequence of instantaneous heart rate of the user; 
   wherein the processing module is configured to determine a heart rate of the user by:
 executing one or more computer-executable instructions associated with a peak detection algorithm to process the data corresponding to the reflected light to detect a plurality of peaks associated with a plurality of beats of the user's heart, 
 determining an R-wave-to-R-wave interval (RR interval) based on the plurality of peaks detected by the peak detection algorithm, 
 determining a confidence level associated with the RR interval, and 
 based on the confidence level associated with the RR interval, selecting either the peak detection algorithm or a frequency analysis algorithm to process data corresponding to the reflected light to determine the sequence of instantaneous heart rates of the user. 
   
     
     
         2 . The wearable physiological measurement system of  claim 1  wherein:
 based on a determination that the confidence level associated with the RR interval is above a predetermined threshold, the processing module uses the plurality of peaks to determine an instantaneous heart rate of the user; and 
 based on a determination that the confidence level associated with the RR interval is equal to or below the predetermined threshold, the processing module executes one or more computer-executable instructions associated with the frequency analysis algorithm to determine an instantaneous heart rate of the user. 
 
     
     
         3 . The wearable physiological measurement system of  claim 1  wherein the processing module selects the peak detection algorithm or the frequency analysis algorithm regardless of a motion status of the user. 
     
     
         4 . The wearable physiological measurement system of  claim 1  wherein the wearable strap further comprises a motion sensor for detecting a motion of the user, and wherein the frequency analysis algorithm processes the data corresponding to the reflected light based on the motion of the user. 
     
     
         5 . The wearable physiological measurement system of  claim 4  wherein the motion sensor is an accelerometer. 
     
     
         6 . The wearable physiological measurement system of  claim 1  wherein the processing module is further configured to determine a heart rate variability of the user based on the sequence of the instantaneous heart rates. 
     
     
         7 . The wearable physiological measurement system of  claim 1  further comprising:
 a visual display device configured to render a user interface for displaying the sequence of the instantaneous heart rates of the user. 
 
     
     
         8 . The wearable physiological measurement system of  claim 1 , further comprising:
 a storage device configured to store the sequence of the instantaneous heart rates and the RR intervals determined by the processing module.   
     
     
         9 . A computer program product comprising non-transitory computer executable code embodied in a non-transitory computer readable medium that, when executing on one or more computing devices, performs the steps of:
 monitoring data from a wearable strap worn by a user, the wearable strap including one or more light emitters for emitting light toward the user's skin and one or more light detectors for receiving light reflected from the user's skin, the data corresponding to the reflected light;   processing the data using a peak detection algorithm to detect a plurality of peaks associated with a plurality of beats of the user's heart;   determining an R-wave-to-R-wave interval (RR interval) based on the plurality of peaks detected by the peak detection algorithm;   determining a confidence level associated with the RR interval;   based on the confidence level associated with the RR interval, selecting either the peak detection algorithm or a frequency analysis algorithm to process the data; and   determining a sequence of instantaneous heart rates of the user using either the peak detection algorithm or the frequency analysis algorithm.   
     
     
         10 . The computer program product of  claim 9  further comprising code that performs the steps of:
 determining whether the confidence level associated with the RR interval is above a predetermined threshold or is equal to or below the predetermined threshold; and 
 determining an instantaneous heart rate of the user using the plurality of peaks when the confidence level is above the predetermined threshold, and determining an instantaneous heart rate of the user using the frequency analysis algorithm when the confidence level is equal to or below the predetermined threshold. 
 
     
     
         11 . The computer program product of  claim 9  further comprising code that performs the step of selecting the peak detection algorithm or the frequency analysis algorithm regardless of a motion status of the user. 
     
     
         12 . The computer program product of  claim 9  wherein the wearable strap further includes a motion sensor for detecting a motion of the user, and wherein the frequency analysis algorithm processes the data corresponding to the reflected light based on the motion of the user. 
     
     
         13 . The computer program product of  claim 9  further comprising code that performs the step of determining a heart rate variability of the user based on the sequence of the instantaneous heart rates. 
     
     
         14 . The computer program product of  claim 9  further comprising code that performs the step of displaying the sequence of the instantaneous heart rates of the user on a user interface. 
     
     
         15 . The computer program product of  claim 9  further comprising code that performs the step of storing the sequence of the instantaneous heart rates and the RR intervals determined by the processing module. 
     
     
         16 . A system comprising:
 a wearable strap configured to be couplable to an appendage of a user, the wearable strap including one or more light emitters for emitting light toward the user's skin and one or more light detectors for receiving light reflected from the user's skin; and   a processing module configured to analyze data corresponding to the reflected light to automatically and continually determine a sequence of instantaneous heart rate of the user, wherein the processing module is configured to determine a heart rate of the user by:
 executing one or more computer-executable instructions associated with a peak detection algorithm to process the data corresponding to the reflected light to detect a plurality of peaks associated with a plurality of beats of the user's heart, 
 determining an R-wave-to-R-wave interval (RR interval) based on the plurality of peaks detected by the peak detection algorithm, 
 determining a confidence level associated with the RR interval, and 
 based on the confidence level associated with the RR interval, selecting either the peak detection algorithm or a frequency analysis algorithm to process data corresponding to the reflected light to determine the sequence of instantaneous heart rates of the user. 
   
     
     
         17 . The system of  claim 16  further comprising a motion sensor for detecting a motion of the user, wherein the frequency analysis algorithm processes the data corresponding to the reflected light based on the motion of the user. 
     
     
         18 . The system of  claim 17  wherein the motion sensor is an accelerometer. 
     
     
         19 . The system of  claim 16  further comprising a visual display device configured to render a user interface for displaying the sequence of the instantaneous heart rates of the user. 
     
     
         20 . The system of  claim 16  further comprising a storage device configured to store the sequence of the instantaneous heart rates and the RR intervals determined by the processing module.