Heart Rate Variability: Are We Ignoring a Harbinger of Health?

George D. Lundberg, MD

A very long time ago, when I ran clinical labs, one of the most ordered tests was the "sed rate" (aka ESR, the erythrocyte sedimentation rate). Easy, quick, and low cost, with high sensitivity but very low specificity. If the sed rate was normal, the patient probably did not have an infectious or inflammatory disease. If it was elevated, they probably did, but no telling what. Later, the C-reactive protein (CRP) test came into common use. Same general inferences: If the CRP was low, the patient was unlikely to have an inflammatory process; if high, they were sick, but we didn't know what with.

Could the heart rate variability (HRV) score come to be thought of similarly? Much as the sed rate and CRP are sensitivity indicators of infectious or inflammatory diseases, might the HRV score be a sensitivity indicator for nervous system (central and autonomic) and cardiovascular (especially heart rhythm) malfunctions?

A substantial and relatively old body of heart rhythm literature ties HRV alterations to posttraumatic stress disorder, physician occupational stress, sleep disorders, depression, autonomic nervous system derangements, various cardiac arrhythmias, fatigue, overexertion, medications, and age itself.

More than 100 million Americans are now believed to use smartwatches or personal fitness monitors.