Cardiovascular risk and responsivity to mental stress: the influence of age, gender and risk factors.

BACKGROUND

Exaggerated cardiovascular and neuroendocrine responses to mental stress may enhance cardiovascular disease risk. Coronary heart disease and hypertension increase in prevalence with advancing age, whereas the excess male/female ratio declines in later middle age. Psychosocial factors may contribute to these changing risk profiles. The hypothesis that cardiovascular and neuroendocrine stress responses are associated with age and gender differences in cardiovascular disease risk was tested.

METHOD

132 healthy men and women from younger (30-40 years) and older (55-66 years) age bands were selected at random from general practice lists. They performed a series of mental stress tests during which blood pressure, heart rate, cardiovascular baroreflex sensitivity, cortisol, respiration patterns and electrodermal activity were monitored. A submaximal exercise test was performed and psychological characteristics were assessed by questionnaire.

RESULTS

At rest, systolic and diastolic blood pressure was higher in men than in women, while cardiac baroreflex sensitivity was greater in younger than in older participants. Blood pressure responses to tasks were substantial, with changes from the baseline averaging 18.6/8.11, 26.0/13.5 and 40.7/19.0 mmHg for computerized problem solving, mirror drawing and speech tasks, respectively. Men and women in the older age band did not differ from each other in blood pressure, heart rate or baroreflex sensitivity responses. Systolic blood pressure responses (mean +/- SEM) were larger in older than in younger women (mean peak difference 6.87 +/- 2.67 mmHg), and in the younger male compared with the younger female groups (mean peak difference 7.20 +/- 2.97 mmHg). Diastolic blood pressure and heart rate responses to mental stress were larger in younger than in older age participants of both sexes. Baroreflex sensitivity was inhibited during behavioural tasks, with significantly greater suppression in younger than in older groups (5.28 +/- 0.52 and 2.62 +/- 0.35 ms/mmHg, respectively). Cortisol responses were greater in men than in women, but did not vary with age. Across the entire sample, systolic blood pressure responsivity was negatively related to the expression of anger. Among older men, heightened blood pressure responses were associated with elevated fasting low-density lipoprotein cholesterol levels, and with lower concentrations of high-density lipoprotein cholesterol.

CONCLUSIONS

Systolic blood pressure stress responsivity increases with age in women but not in men. Other data do not support the notion that stress responsivity mediates age and gender differences in cardiovascular disease risk. However, in middle-aged men, ex-aggerated cardiovascular stress responsivity is associated with an unfavourable risk profile.