Lower social position is associated with faster and less variable heart rates, according to a new study. Both conditions are “almost certainly bad for heart health, being associated with higher risk of Heart attack and death,” said Dr. Harry Hemingway, who led the study.

The findings of laboratory and clinical studies suggest that the nervous system responds to chronic psychosocial   stress resulting in adverse metabolic consequences, which may explain the association between low social position and high risk of Heart disease, Hemingway and his colleagues explain in the online issue of Circulation: Journal of the American Heart Association.

The researchers, from University College London, tested this hypothesis in 2,197 healthy men between 45 and 68 years old who worked as civil servants in senior executive, mid-level or low-level positions. The participants’ heart rate variability was measured and the men answered questionnaires covering employment grade, psychosocial factors, and aspects of lifestyle.

After adjusting the data for potentially confounding factors, the investigators found that the heart rates of men with low-level positions were on average 3.2 beats per minute faster than men with top-level positions, a statistically significant difference. The men with lower-level jobs also had low heart rate variability compared with men with higher-level jobs.

Behaviors having adverse health effects, such as smoking, low levels of exercise, poor diet, and alcohol intake, as well as adverse psychosocial factors, such as the feeling of little control over one’s job and depression, correlated strongly with low heart rate variability.

There was also a strong relationship between higher heart rates and lower heart rate variability and several components of the metabolic syndrome including waist circumference, blood pressure, and cholesterol and glucose levels.

Hemingway said these results show that there is a “social hierarchy in heart rate and its subconscious fine tuning. There is also a social hierarchy in the cluster of risk factors known as the metabolic syndrome.”

He concluded, “We need to know how social position ‘gets under the skin’ and causes heart disease.”

SOURCE: Circulation, June 6, 2005.