Hello Chris, unfortunately it is not possible as recording your heart rate via one's finger or even pulse monitor (like via a fibit, etc) does not record the difference in time "between" each beat.  Typically this variance in each beat is a fraction of a second different from one beat to another.  Hope that clears it up.

Ah, that makes sense, thanks. In the video the guy said heart rate variability is a measure of fitness, but from his description it sounded more like a lagging indicator in the sense that when I'm sick or stressed the variability goes down and when I'm not it goes up. Did I interpret that correct?