Long Work Hours Linked to Hypertension

Xavier Trudel, PhD

New data from Laval University in Canada is shedding light on the impact long work hours and working too much can have on a person’s risk of developing hypertension.

The 5-year study revealed people working more than 40 hours per week had an increased risk of having masked hypertension and sustained hypertension, even after accounting for variables including job strain, occupation, smoking status, and other factors.

"Both masked and sustained high blood pressure are linked to higher cardiovascular disease risk," said lead investigator Xavier Trudel, PhD, assistant professor in the social and preventive medicine department at Laval University in Quebec, Canada. "People should be aware that long work hours might affect their heart health.”

In an effort to build on previous data examining the association between hypertension and long working hours, investigators carried out a study examining the prevalence of masked and sustained hypertension in a cohort of white-collar workers in Quebec City. A total of 3547 participants were included in the study, all of whom underwent assessments at 3 points—years 1, 3, and 5—over the course of the 5-year study.

A wearable blood pressure reader simulated in-clinic blood pressure readings. The reader took resting blood pressure readings 3 times in one morning and 20 additional readings—at an interval of 15 minutes for the rest of the workday. Self-reported work hours were divided into 4 categories: 21 to 34 hours, 35 to 40 hours, 41 to 48 hours, and 49 or more hours per week.

For the purpose of the analysis, ambulatory blood pressure was defined as the mean of the readings taken every 15 minutes during daytime work hours. Investigators classified masked hypertension as clinic blood pressure less than 140/90 mmHg and ambulatory blood pressure greater than or equal to 135/85 mmHg. Sustained hypertension was classified as clinic blood pressure greater or equal to 140/90 mmHg and ambulatory blood pressure greater than or equal to 135/85 mmHg—patients receiving antihypertensive medications were also classified as having sustained hypertension.

The overall rates of masked and sustained hypertension in the study cohort were 13.5% and 18.7%, respectively. In adjusted analyses, investigators observed participants working 41 to 48(Prevalence Ratio (PR)=1.54; 95% CI, 1.09—2.19) hours per week and those working 49 or more (PR=1.76; 95% CI, 1.12–2.77) had a higher prevalence of masked hypertension.

Additionally, a similar effect was observed when examining rates of sustained hypertension with the 2 highest categories of working hours saw the greatest prevalence ((PR=1.33 [95% CI, 0.99— 1.76);(PR=1.66; 95% CI, 1.15–2.50)). Based on the outcomes of the analysis, investigators concluded working long hours was an independent risk factor for both sustained and masked hypertension.

This study, titled “Long Working Hours and the Prevalence of Masked and Sustained Hypertension,” was published online in Hypertension.