Provided according to embodiments of the invention are methods, devices and systems for monitoring respiration. Methods described herein include isolating an isolated DC component signal stream, and optionally an isolated AC component signal stream, from the raw PPG signal calculating a waveform parameter using at least a portion of the isolated DC component signal stream, and optionally, a corresponding portion of the raw PPG signal stream and/or the isolated AC component signal stream and monitoring respiration in the individual by analyzing the waveform parameter over time.
