Effects of Chronic Stress

Occupational stress has been investigated in several studies. In a study of 50 normotensive working women doing technical and clerical jobs, who also kept diaries describing their activities, emotions, and perceptions of stress, it was found that the average pressures were 116/78 mmHg at work, 113/74 mmHg at home, and 102/63 mmHg during sleep.

The most powerful behavioral predictor of systolic pressure was the perception that one’s job is stressful, which was associated with higher pressures in all three situations - at work, at home, and during sleep. The perception that there was more stress at work than at home on the day of the study was associated with higher systolic pressures at work, but not at home or during sleep. Potential sources of domestic stress were also related to blood pressure.

Being married was associated with higher work diastolic pressures, while having children was associated with higher systolic and diastolic pressures both at work and at home. Women who reported higher levels of stress at home than at work also had relatively higher diastolic pressures at home than at work. Thus, single women whose main source of stress was at work showed a pattern similar to the one seen in men, while married women with children, whose level of stress may be higher at home, did not show the typical decrease of blood pressure when they returned home.

Young physicians, when on call for the emergency room, show an elevation of ambulatory blood pressure in comparison to a weekend day, which exceeded 10 mmHg for systolic pressure in 40% of cases. Blood pressure while asleep was not affected, however.

In this case the acute work stress raised the blood pressure during the exposure to stress, but to what extent this was due to mental as to opposed to physical activity is not clear. A very different picture is obtained with more chronic stress: subjects whose jobs are characterized as high strain (defined by a combination of high demands and low control) have elevated ambulatory blood pressures in comparison with subjects in less stressful jobs, not only during the hours of work, but also, more surprisingly, while they are at home and asleep.

That this is a causal relationship is suggested by the finding that over a 3 year period those who remain in high-strain jobs show a persistent elevation of blood pressure, and those whose jobs become less stressful show a decrease of pressure.

These results provide the strongest evidence to date that exposure to chronic stress can elevate the blood pressure throughout the 24 h period. Interestingly, there appears to be no relation between blood pressure and job strain in women, despite the fact that women are more likely than men to be in high-strain jobs. This might be because women react to different types of stress than men: another study found that lack of social support predicted ambulatory blood pressure in women, while hostility was a better predictor in men.