If you have a stressful job your chances of developing heart disease are considerably higher compared to a person who does not have a stressful job, according to an article published in the European Heart Journal.

Researchers examined details on over 10,000 UK civil servants – Whitehall employees, from messengers to top bosses. They found that civil servants under the age of 50 who rated their jobs as stressful ran a 70% higher chance of developing heart disease compared to civil servants who did not perceive their jobs to be stressful. Not only were the stressed civil servants less able to eat properly and do exercise because of time constraints, the researchers report that they also displayed signs of considerable biochemical changes.

This very large, long-term study started over 40 years ago, with close follow-up and monitoring of this cohort starting in 1985 and continuing until today.

The monitoring covered –

— how each civil servant rated his/her job
— heart rates
— blood pressure readings
— level of cortisol in the blood (a stress hormone)
— eating habits
— drinking habits
— smoking habits

The researchers examined how each person had developed CHD (coronary heart disease) or had a heart attack, as well as listing how many died.

According to team leader, Dr Tarani Chandola, of University College London, a 12-year follow up found a close link between CHD and job stress. The link was more pronounced among male employees than female ones, Chandola added. The association was much less evident as employees reached retirement age and were less exposed to or bothered by work stress.

Even though stressed civil servants did less exercise and had a worse diet than the majority of their colleagues, it did not appear that more of them had a significantly higher drinking problem, the authors wrote. However, the researchers stress that lifestyle was an important factor in the development of coronary heart disease.

Previous studies had shown an association between stress and illness; however why the link was there has always been rather unclear. The researchers in this study say they understand the biological mechanisms – mechanisms that have nothing to do with lifestyle (no matter what the lifestyle is, if the job is stressful, these mechanisms are persistently there).

They explain that stress seems to have an impact on a part of our nervous system which regulates how the heart works, how well it beats – a part of our nervous system that regulates our pulse rate. They found that those who were stressed also had poor vagal tone – impulses from the vagus nerve producing inhibition of the heartbeat – impulses which regulate our heartbeat. They also found that our system which releases hormones, the neuroendocrine system, is somewhat disrupted in people who are stressed. Nearly all the civil servant who rated their jobs as stressful had elevated levels of blood cortisol.

The risk of heart disease and heart attack was present for stressed employees no matter what position they had (status was not a factor, stress was).

The researchers concluded “Work stress may be an important determinant of CHD among working-age populations, which is mediated through indirect effects on health behaviors and direct effects on neuroendocrine stress pathways.”

Funding
The Whitehall II study has been supported by grants from the Medical Research Council; Economic and Social Research Council; British Heart Foundation; Health and Safety Executive; Department of Health; National Heart Lung and Blood Institute (HL36310), US, NIH; National Institute on Aging (AG13196), US, NIH; Agency for Health Care Policy Research (HS06516); and the John D. and Catherine T. MacArthur Foundation Research Networks on Successful Midlife Development and Socio-economic Status and Health. M.M. is supported by an MRC Research Professorship, H.H. by a public health career scientist award from the Department of Health, and M.K. by the Academy of Finland (grant 117 604).

“Work stress and coronary heart disease: what are the mechanisms?”
Tarani Chandola1, Annie Britton, Eric Brunner, Harry Hemingway, Marek Malik, Meena Kumari, Ellena Badrick, Mika Kivimaki and Michael Marmot
European Heart Journal, doi:10.1093/eurheartj/ehm584
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Written by – Christian Nordqvist