System and method for determining a heart rate and a heart rate variability of an individual is disclosed. An audio signal of heart sound is amplified. Subsequently, an envelope of the amplified audio signal is detected by squaring of the amplified audio signal to obtain emphasized high amplitude components and diminished low amplitude components of the audio signal, applying a band pass filter on the audio signal upon squaring and applying a Teager-Kaiser Energy Operator (TKEO) on the filtered audio signal. Peaks in the envelope of the audio signal are detected by calculating difference in magnitude of a point in the audio signal with an average of magnitude of earlier points in the audio signal from the last detected peak or the initial sample value in the processing window when no peak is detected. Based on the peaks detected, heart rate and heart rate variability for the individual are determined.