Heart rate fragmentation: A novel analytic approach to early allostatic
load detection among healthy adults
Abstract
The current study explores an emerging cardiac metric, heart rate
fragmentation (HRF), as a novel biomarker for allostatic load (AL). HRF
may better address the limitations of existing cardiac biomarkers (e.g.,
confounds and interpretation consistency) in applied research settings,
with nonclinical samples. The study’s objectives were: 1) can HRF
represent response to psychological stress and 2) can resting HRF be
used as a measure of predicting subclinical mental health symptoms. One
hundred and fifty-six (n = 156; 75% female) undergraduate students were
fitted with a chest band to monitor cardiovascular activity, and
completed online demographic and psychosocial surveys in which they were
grouped as healthy or displaying probable mental health symptoms (pMH; n
= 94, 60.25%) based on respective inventory thresholds for depression,
anxiety, and posttraumatic stress disorder. Cardiovascular activity was
measured capturing the three R’s of cardiac vagal control: a resting
baseline, a reactive acute stressor task, and a paced breathing
recovery. Results supported the first hypothesis, in that that HRF
significantly differentiated between each RRR condition (p <
0.001). While healthy and pMH individuals did not significantly differ
within individual conditions, exploratory analyses revealed healthy
individuals displayed significantly larger change in HRF reactivity
between conditions (p’s < 0.001) in comparison to pMH, which
displayed a more blunted pattern. Overall, this study establishes
associations between HRF and mental health, and serves as a promising
new biomarker that may identify AL in samples that may be otherwise
considered “healthy”, while addressing the limitations of prior
biomarkers in non-clinical studies.