Why work-stress means 'bigger risk' of heart disease

Their study of more than 10,000 civil servants uncovered the strongest evidence yet of how stress can lead to coronary heart disease (CHD). Published in the European Heart Journal, the researchers sought to look at the mechanisms of how stress affected the body.

As well as impacting on the nervous system and other biological mechanisms, work-stress increased the risk of heart disease by affecting how people led their lives, according to the study, including what they ate and whether or not they exercised.

Researchers collected evidence on the incidence of heart disease, deaths from CHD, non-fatal heart attacks, angina and heart rate variability. They also looked at increases in levels of the "stress hormone" cortisol in the morning, metabolic syndrome and factors such as diet, exercise, smoking and drinking.

The overall study, which has been running since 1985, is led by Sir Michael Marmot, professor of epidemiology and public health at University College London (UCL).

Strong association

Dr Tarani Chandola, a senior lecturer in UCL's Department of Epidemiology and Public Health, and first author on the latest paper, said: "Stress at work is associated with an increased risk of coronary heart disease, but the mechanisms underlying this association have remained unclear until now.

"During 12 years of follow-up, we found that chronic work stress was associated with CHD and this association was stronger among both men and women aged under 50 - their risk of CHD was an average of 68% more than for people who reported no stress at work."

He explained that work-stress impacted on the nervous system, effectively lowering heart rate variability. Greater stress also produced other unwelcome biological responses, such as higher than normal morning levels of cortisol.

Dr Chandola went on to say: "Work stress is associated with a poorer diet in terms of eating less fruit and vegetables, and less exercise. It has also been linked to problem drinking, although not in this study.

"In this study, around 32% of the effect of work stress on CHD could be explained by its effect on health behaviours and the metabolic syndrome."

'Unhealthy behaviours'

June Davison, cardiac nurse at the British Heart Foundation (BHF), said: "This new research further contributes to our understanding of how stress at work may increase the risk of coronary heart disease.

"It takes another step towards deciphering how stress may alter our body's chemistry to affect our heart health. However we still need to further understand the mechanisms of how this may directly lead to heart disease."

She added: "The study also reinforces what has been identified by previous research, that stress at work is often associated with unhealthy behaviours such as smoking, lack of exercise and a poor diet - all which can impact on heart health.

"There are many ways that we can help ourselves by learning how to cope with stressful situations. Keeping fit and active also helps to relieve stress and therefore reduce the risk of heart disease."