Ask the Doctors by Eve Glazier, M.D. and Elizabeth Ko, M.D

Study Links Overtime to Masked Hypertension

Dear Doctor: I heard about a study that says working overtime gives you high blood pressure. My husband just joined a competitive company, and he’s expected to work a lot of extra hours. He’s already a Type A kind of guy, and I’m worried.

Dear Reader: You’re referring to the results of research published last December that found a connection between putting in long hours at work each week and an increased risk of developing high blood pressure. More specifically, the study uncovered a link to a condition known as “masked hypertension.” This is when blood pressure readings in the doctor’s office are normal but then rise to elevated -- and even dangerous -- levels outside of the clinical setting. That makes diagnosis and treatment difficult and may put someone at higher risk of heart problems and stroke.

In the study, published in the journal Hypertension, researchers in Canada followed 3,500 office workers for five years. Participants in the study wore a device that measured their blood pressure every 15 minutes. The researchers also obtained daily blood pressure readings while the workers were at rest. The goal was to identify periods of normal blood pressure, sustained high blood pressure and masked hypertension. After adjusting the resulting data for lifestyle factors such as weight and smoking, existing medical conditions such as diabetes, family medical history and job strain, the researchers found a correlation between how much overtime someone worked and their blood pressure.

Overall, the study found a 70% higher risk of masked hypertension among workers who put in 49 or more hours per week as compared to those with a workweek of 35 hours or fewer. They also found that the overtime group had a 66% higher risk of sustained high blood pressure. These are blood pressure readings that remain high and can be measured in a clinical setting. As little as one to nine hours of overtime was linked to a significant increase in risk of both types of hypertension. The results held true for both women and men.

Analysis of previous research, which also finds a connection between a long workweek and developing high blood pressure, suggests stress and loss of sleep as potential causes. But because the number-crunching in the Canadian study takes those factors into consideration, the authors suspect some other mechanism is at work. Considering that the study looked at white-collar workers, who spend the lion’s share of their time behind a desk, recent revelations about the adverse health effects of prolonged sitting may hold a clue. These include weight gain, increased risk of developing metabolic diseases like Type 2 diabetes, and, yes, hypertension. It will be interesting to see if these parallel avenues of research converge.

Meanwhile, considering the demands of your husband’s new job, as well as your description of him as a driven Type A personality, we think it would be wise for him to check in with his health care provider. He may be advised to monitor his blood pressure with a wearable monitor, which would allow a diagnosis, and, if needed, appropriate treatment.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)