An apparatus for determining data pertaining to the heart rate, respiratory rate, and/or blood pressure of a human subject based on pulse waveform analysis and an apparatus for determining a medical condition of a human subject. The apparatus determining data comprises a control unit and a means for providing pulse wave data representative of a heart beat of a human subject. The subject has a body height, an age, and a gender, and is further characterized by being a smoker or non-smoker and by a measure of percentage of body fat (e.g. BMI, BFP, etc.). The control unit is configured for receiving the pulse wave data, selecting a portion of the pulse wave data indicative of a plurality of heart periods, and, for the portion of the pulse wave data indicative of a plurality of heart periods: determining a blood pressure variability based on the pulse wave data of the portion of the pulse wave data indicative of a plurality of heart periods； determining a respiratory rate variability based on the pulse wave data of the portion of the pulse wave data indicative of a plurality of heart periods； and determining a heart rate variability based on the pulse wave data of the portion of the pulse wave data indicative of a plurality of heart periods. Further, at least one correlation value based on at least two of the blood pressure variability, the respiratory rate variability, and the heart rate variability is determined and a medical condition of the subject is determined based on the at least one correlation value. The apparatus for determining a medical condition of a human subject comprises a control unit and a means for providing pulse wave data representative of a heart beat of the human subject. The control unit is configured to perform the steps of receiving the pulse wave data, selecting a portion of the pulse wave data indicative of a plurality of heart periods, determining a first index indicative of a heart rate variability based on the pulse wave data of the portio
