In embodiments, a persons heart rate variability (HRV) is determined by analyzing different color channels of a video of the persons skin. Various statistics are then derived from the HRV.The persons HRV statistics are processed using comparisons with HRV statistics of other people with known athletic through sedentary lifestyles, to obtain the persons fitness index. An analogous processing is carried out using comparisons of the persons HRV statistics to those of people with known levels of proficiency in specific sports, to obtain the persons sport-specific fitness index for the person.
