Physiological and Personality Measures as Potential Factors Associated with Cardiac Coherence Training Effects on Symptoms Reduction: A Pilot Study on Healthcare Workers.

Objective: High cardiovascular risk (i.e., increased heart rate (HR) and reduced HR variability (HRV)) is common among healthcare workers. HRV biofeedback (HRVB) and cardiac coherence training (CCT) aim to minimize cardiac reactivity through breathing and cognitive exercises. Despite the numerous evidence, there are no studies that have investigated the potential role of psychological and psychophysiological factors on its efficacy. Method: Twenty healthcare workers (i.e., doctors, nurses, psychologists, etc.) employed at the San Giacomo Hospital of Physical Medicine and Rehabilitation in Ponte dell'Olio (Piacenza, Italy) completed the Symptom Checklist-90-Revised (SCL-90-R) and the 16 Personality Factors Questionnaire (16PF). Then, skin conductance (SC), HR, and HRV, with frequency domain analysis (i.e., LF-HRV, HF-HRV, LF/HF ratio), were recorded at baseline and under induced stressors through a Psychophysiological Stress Profile (PPS). Following CCT, its efficacy was measured through a comparison of psychological symptoms (i.e., SCL-90-R) and baseline, reactivity, and recovery psychophysiological values (i.e., SC, HR, and HRV). Additionally, the coherence index (CI), corresponding to the cardiac coherence (CC) score, as well as its cumulative score, the achievement score (AS), were collected. Nonetheless, the percentage of CI (%INITIAL-CI) and AS (%INITIAL-AS) variation compared to the initial session was calculated. Results: Lower levels of somatizations, depression, obsessions and compulsions, and hostility were observed, as well as lower reactivity to HR and better recovery of SC at T1. On the other hand, an increase in LF-HRV and a higher HRV (LF/HF ratio) in general were appreciated. Furthermore, the value of %INITIAL-CI of the last CCT session positively correlated with the post-stress recovery SC value at T0, as well as with some personality traits connected to self-regulation capability. Specifically, emotional stability positively correlated with %INITIAL-CI and %INITIAL-AS. Furthermore, the latter was also significantly associated with perseverance. Conclusions: Although the absence of the control group should be noted as a limitation, the purpose is to emphasize the correlations between CI and AS at the end of the intervention and the psychophysiological and personality measures.