JMIR Publications

ABSTRACT

Background:

Intensive Care Unit (ICU) residents are exposed to high stress levels due to the intense nature of their work, which can impact their mental health and job performance. Understanding the relationship between heart rate measured through wearable devices and self-reported stress can aid in developing targeted interventions.

Objective:

This exploratory study analyzed long-term heart rate data and self-reported stress levels and stressors in ICU residents to examine correlations between physiological responses, stress levels, and daily stressors reported.

Methods:

A secondary data analysis was conducted on heart rate measurements and stress assessments collected from 57 ICU residents over a three-week period using Fitbit Charge 3 devices. These devices captured continuous physiological data alongside daily surveys that assessed stress levels and identified stressors. Data preprocessing included normalization and alignment of heart rate and survey timestamps. The study employed Pearson correlation, paired t-tests, and mixed-effect models to analyze the relationship between heart rate features and stress indicators.

Results:

Our findings reveal complex interactions between stress levels and heart rate responses. Correlation analysis between stress levels and median heart rate showed that lower percentile heart rates had modest correlations with stress, whereas higher percentiles did not correlate significantly. A significant t-test analysis indicated substantial differences in stress levels reported in midday versus end-of-day surveys, although these differences did not correspond to expected changes in heart rate patterns. Additionally, we explored the impact of daily stressors on stress level changes, finding that stressors related to "other health" issues had the highest positive correlation with stress changes, while the absence of specified stressors typically corresponded with lesser changes in stress levels. According to our mixed-effects model, stress levels significantly influence heart rate variations when hierarchical data is taken into account. As the stress level increased, the mean heart rate increased significantly, highlighting the importance of advanced statistical techniques in revealing the true dynamics of stress response.

Conclusions:

This study highlights the complexity of stress responses in ICU residents and the limitations of using heart rate data as an independent indicator of stress. Future research should consider integrating physiological and psychological measures to gain a comprehensive understanding of stress.