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Six Dijkstra WMC1,2, Soer R1,3, Bieleman HJ1, McCraty R4, Oosterveld FGJ1, Gross DP5, Reneman MF2
1Saxion University of Applied Sciences, School of Health, Enschede, Netherlands, 2University of Groningen, University Medical Center Groningen, Department of Rehabilitation Medicine, Groningen, Netherlands, 3University of Groningen, University Medical Center Groningen, Groningen Spine Center, Groningen, Netherlands, 4Heartmath LCC, Boulder Creek, United States, 5University of Alberta, Department of Physical Therapy, Edmonton, Canada
Background: Occupational physiotherapists work to improve the health and employability of employees. A workers' health assessment (WHA) is one of the tools used in the Netherlands to screen for risks: work-, health- and lifestyle-related determinants are assessed and advice is provided when appropriate.
Heart rate variability (HRV) is related to physical and mental health problems that are known reasons for sick-leave or early retirement, like cardiovascular diseases and stress related symptoms. HRV is a measure of the natural beat-to-beat changes in heart rate and may be related to the ability to adapt effectively to stress and environmental demands. HRV decreases with age. Although HRV could be of interest in a WHA, it is not often used because the traditional measurement is time-consuming (24 h). A recently developed 1-minute-protocol could allow large scale HRV-measurement for screening of health problems and, potentially, sustained employability, however it's value is unknown.
Purpose: To explore the association between a 1-minute HRV measurement and measures of physical and mental health in a heterogeneous group of employees (blue and white collar).
Methods: Cross-sectional design with 877 Dutch employees who were assessed during a WHA. All employees provided informed consent. Personal and job characteristics were measured with questionnaires including workability (WAI), psychological (GHQ-12), physical and mental problems (QEEW), work engagement (UBES9), and lifestyle factors (physical activity, smoking, alcohol-consumption, diet, recreation). Biometry was measured (body mass index (BMI), waist- circumference, blood pressure, glucose, cholesterol) by occupational physiotherapists. HRV was assessed with a 1-minute paced deep-breathing protocol and expressed as mean heart rate range (MHRR). Lower age-corrected MHRR indicates a higher health risk. Groups were classified age-adjusted for HRV (HRV mean-2sd=very low, mean-2sd HRV mean-1sd= low, HRV>mean-1sd=normal-high) and compared for personal and job characteristics. Pearson correlations between raw MHRR and other measures were calculated. Significant univariable correlations (p 0.05) were entered in a linear regression model to explore the multivariable association with MHRR.
Results: Age, education, years of employment, BMI and waist-circumference differed significantly between groups with very low, low and normal-high HRV. Correlations controlled for age were significant between MHRR and BMI, waist-circumference, and reported physical activity. In the multivariable analyses 17.6% of variance was explained: low HRV correlated with higher age, higher BMI, and more reported physically activity.
Conclusion(s): HRV was significantly associated with age, BMI and with reported physical activity. The correlation with age and BMI was inverse as expected. The correlation with physical activity was not expected. Physical activity was self-reported and may not fully reflect actual activity, thereby biasing results. Additionally, the observed association with physical activity, though statistically significant, was small and clinical relevance is questionable.
Implications: Exploratory results provide a first glance of the utility of a 1-minute paced deep-breathing HRV protocol as part of a preventive WHA. Because of the cross sectional nature of the study and modest explained variance, caution has to be taken for individual decision making when using only MHRR as a screen for future health and sustained employability.
Keywords: Occupational Physiotherapy, HRV, Diagnostic Techniques and Procedures
Funding acknowledgements: This study was funded by Expertise Center Tech For Future in The Netherlands (TFF150101 SHIFT).
Heart rate variability (HRV) is related to physical and mental health problems that are known reasons for sick-leave or early retirement, like cardiovascular diseases and stress related symptoms. HRV is a measure of the natural beat-to-beat changes in heart rate and may be related to the ability to adapt effectively to stress and environmental demands. HRV decreases with age. Although HRV could be of interest in a WHA, it is not often used because the traditional measurement is time-consuming (24 h). A recently developed 1-minute-protocol could allow large scale HRV-measurement for screening of health problems and, potentially, sustained employability, however it's value is unknown.
Purpose: To explore the association between a 1-minute HRV measurement and measures of physical and mental health in a heterogeneous group of employees (blue and white collar).
Methods: Cross-sectional design with 877 Dutch employees who were assessed during a WHA. All employees provided informed consent. Personal and job characteristics were measured with questionnaires including workability (WAI), psychological (GHQ-12), physical and mental problems (QEEW), work engagement (UBES9), and lifestyle factors (physical activity, smoking, alcohol-consumption, diet, recreation). Biometry was measured (body mass index (BMI), waist- circumference, blood pressure, glucose, cholesterol) by occupational physiotherapists. HRV was assessed with a 1-minute paced deep-breathing protocol and expressed as mean heart rate range (MHRR). Lower age-corrected MHRR indicates a higher health risk. Groups were classified age-adjusted for HRV (HRV mean-2sd=very low, mean-2sd HRV mean-1sd= low, HRV>mean-1sd=normal-high) and compared for personal and job characteristics. Pearson correlations between raw MHRR and other measures were calculated. Significant univariable correlations (p 0.05) were entered in a linear regression model to explore the multivariable association with MHRR.
Results: Age, education, years of employment, BMI and waist-circumference differed significantly between groups with very low, low and normal-high HRV. Correlations controlled for age were significant between MHRR and BMI, waist-circumference, and reported physical activity. In the multivariable analyses 17.6% of variance was explained: low HRV correlated with higher age, higher BMI, and more reported physically activity.
Conclusion(s): HRV was significantly associated with age, BMI and with reported physical activity. The correlation with age and BMI was inverse as expected. The correlation with physical activity was not expected. Physical activity was self-reported and may not fully reflect actual activity, thereby biasing results. Additionally, the observed association with physical activity, though statistically significant, was small and clinical relevance is questionable.
Implications: Exploratory results provide a first glance of the utility of a 1-minute paced deep-breathing HRV protocol as part of a preventive WHA. Because of the cross sectional nature of the study and modest explained variance, caution has to be taken for individual decision making when using only MHRR as a screen for future health and sustained employability.
Keywords: Occupational Physiotherapy, HRV, Diagnostic Techniques and Procedures
Funding acknowledgements: This study was funded by Expertise Center Tech For Future in The Netherlands (TFF150101 SHIFT).
Topic: Occupational health & ergonomics
Ethics approval required: No
Institution: University Medical Center Groningen in The Netherlands
Ethics committee: The Ethics Board at the University Medical Center Groningen
Reason not required: Formal approval of the study was not necessary because all workers were subjected to care as usual only.
All authors, affiliations and abstracts have been published as submitted.
