Provided in embodiments herein are computer-implemented methods and systems for respiratory monitoring. Some embodiments include obtaining a PPG signal stream from a central source site of the individual； identifying peaks and troughs of the PPG signal stream within a predetermined epoch, wherein a time between peaks or a time between troughs corresponds to a heart rate of the individual； determining significant local maxima of peak amplitudes and significant local minima of trough amplitudes within the predetermined epoch, wherein each significant local maxima of peak amplitude corresponds to an onset of the individual's respiratory effort to exhale and each significant local minima of trough amplitude corresponds to an onset of the individual's respiratory effort to inhale； calculating the number of significant local maxima, significant local minima, or both, during the predetermined epoch to determine the number of respiratory efforts in the predetermined epoch； and displaying the number of respiratory efforts in the predetermined epoch on a computer monitor.
