A processor-implemented method for extracting breathing patterns from PPG signals, the method comprising: obtaining, via one or more hardware processors, from an accelerometer sensor embodied in a wearable device, an accelerometer signal indicative of motion of a subject; computing, via the one or more hardware processors, mean and standard deviation values of the accelerometer signal to determine whether the subject is in motion; and performing, via the one or more hardware processors, based on the determination: discarding the PPG signals captured from the wearable device upon determination of the subject to be in motion, or generating a plurality of filter coefficients upon determination of the subject to be in rest position; designing, via the one or more hardware processors, a filter for extracting breathing patterns from PPG signals, wherein designing the filter comprises: defining filter specifications for extraction of breathing pattern from the PPG signals, wherein the filter specifications comprises a type, an order and a cut-off frequency of the filter, wherein the filter specifications for the extraction of the breathing pattern comprises Infinite Impulse response Butter-worth band-pass filter of order 4, with a cut-off frequency of 0.2-1 Hz to include slow breathing rates of 12-15 BrPMupto fast breathing rates of 50-55 BrPM, generating a transfer function associated with the filter specifications, and computing the plurality of filter coefficients using filtfilt function for allowing filtering of the PPG signals, wherein the filtfilt function performs zero-phase digital filtering by processing an input data in both the forward and reverse directions; generating, using the filter comprising the plurality of filter coefficients, filtered PPG signals by removing DC component from PPG signals obtained from the wearable device worn by the subject via the one or more hardware processors, the filtered PPG signals indicative of the breathing pattern of the subject. obtaining, via one or more hardware processors, from an accelerometer sensor embodied in a wearable device, an accelerometer signal indicative of motion of a subject; computing, via the one or more hardware processors, mean and standard deviation values of the accelerometer signal to determine whether the subject is in motion; and performing, via the one or more hardware processors, based on the determination: discarding the PPG signals captured from the wearable device upon determination of the subject to be in motion, or generating a plurality of filter coefficients upon determination of the subject to be in rest position; discarding the PPG signals captured from the wearable device upon determination of the subject to be in motion, or generating a plurality of filter coefficients upon determination of the subject to be in rest position; designing, via the one or more hardware processors, a filter for extracting breathing patterns from PPG signals, wherein designing the filter comprises: defining filter specifications for extraction of breathing pattern from the PPG signals, wherein the filter specifications comprises a type, an order and a cut-off frequency of the filter, wherein the filter specifications for the extraction of the breathing pattern comprises Infinite Impulse response Butter-worth band-pass filter of order 4, with a cut-off frequency of 0.2-1 Hz to include slow breathing rates of 12-15 BrPMupto fast breathing rates of 50-55 BrPM, generating a transfer function associated with the filter specifications, and computing the plurality of filter coefficients using filtfilt function for allowing filtering of the PPG signals, wherein the filtfilt function performs zero-phase digital filtering by processing an input data in both the forward and reverse directions; generating, using the filter comprising the plurality of filter coefficients, filtered PPG signals by removing DC component from PPG signals obtained from the wearable device worn by the subject via the one or more hardware processors, the filtered PPG signals indicative of the breathing pattern of the subject. defining filter specifications for extraction of breathing pattern from the PPG signals, wherein the filter specifications comprises a type, an order and a cut-off frequency of the filter, wherein the filter specifications for the extraction of the breathing pattern comprises Infinite Impulse response Butter-worth band-pass filter of order 4, with a cut-off frequency of 0.2-1 Hz to include slow breathing rates of 12-15 BrPMupto fast breathing rates of 50-55 BrPM, generating a transfer function associated with the filter specifications, and computing the plurality of filter coefficients using filtfilt function for allowing filtering of the PPG signals, wherein the filtfilt function performs zero-phase digital filtering by processing an input data in both the forward and reverse directions; generating, using the filter comprising the plurality of filter coefficients, filtered PPG signals by removing DC component from PPG signals obtained from the wearable device worn by the subject via the one or more hardware processors, the filtered PPG signals indicative of the breathing pattern of the subject.