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We have previously shown that plasma levels of endothelium-derived tissue-type plasminogen activator (t-PA) increase during mental stress. The aim of the study was to investigate in vivo release in an intact human muscle vascular bed. Eleven healthy young males (22-36 yrs) were studied at rest and during 10 min of mental stress (forced arithmetic). Net release or uptake were assessed by arterio-venous (AV) concentration gradients across the forearm of t-PA antigen and t-PA activity, and plasminogen activator inhibitor antigen type 1 (PAI-1). Forearm blood flow was measured by venous occlusion plethysmography. At rest, there was a positive AV-difference of t-PA activity across the forearm indicating a net release of t-PA activity of approximately 3.7 fmol x min-1 x 100 ml-1 (Wilcoxon's signed rank test vs 0, p = 0.01). However, t-PA antigen showed a variable release pattern. On the average, there was a net release of 0.17 ng x min-1 x 100 ml-1 after 60 min of rest (Wilcoxon vs 0, p = 0.07). PAI-1 antigen showed net release at rest. In response to stress, forearm blood flow increased from 1.9 to 2.9 ml x min-1 x 100 ml-1 (ANOVA, p = 0.007), and net release of t-PA activity increased to 9.8 fmol x min-1 x 100 ml-1 (ANOVA, p = 0.01 compared with rest). Arterial and venous plasma t-PA levels also increased significantly during stress (ANOVA, p < 0.01). t-PA antigen showed a similar but less pronounced release pattern during stress.(ABSTRACT TRUNCATED AT 250 WORDS)

Objective: The aim of the study was to investigate the haemodynamic effects of hormonal changes during the menstrual cycle in 11 hypertensive women aged between 29 and 38 years., Design: In randomized order, the subjects were examined on days 2-7 (follicular phase) and on days 20-24 (luteal phase). All medication was withdrawn on average 5 weeks prior to the experiment. The results in the hypertensive group were compared with those of a control group consisting of 11 normotensive women aged between 21 and 46 years who had earlier taken part in an identical experiment., Methods: A standardized mental stress test and a 24-h ambulatory blood pressure and heart rate recording were performed. RESULTS. Prestress resting heart rate was significantly higher in the hypertensive group and a significant difference was maintained throughout the entire stress experiment. Heart rate, systolic and diastolic blood pressure increased highly significantly in both groups during the exposure to mental stress, but no difference in heart rate or blood pressure reactivity between the normotensive and hypertensive groups was found in either phase. Heart rate reactivity did not differ during the two phases in the hypertensive group, in contrast to our previous findings in normotensives. During 24-h ambulatory recording both groups had slightly but significantly higher heart rate and systolic blood pressure in the luteal phase. In the hypertensives the diastolic blood pressure was also higher in this phase. Both groups had significantly higher serum oestradiol and progesterone levels in the luteal phase., Conclusions: The findings of the present study support the hypothesis that female sex hormones affect cardiovascular control in both normotensive and hypertensive women.

1. To evaluate the short-term reproducibility of heart rate, oscillometrically determined blood pressure, antecubital venous plasma catecholamine concentrations and subjective responses to strictly standardized mental arithmetic, we performed two identical tests 1 h apart in 14 young, healthy and normotensive male subjects (age 22-35 years). 2. Heart rate and blood pressure responses to the two stress tests were highly correlated, when expressed both as correlations between levels attained during stress (rs greater than 0.80 throughout) and as absolute reactivity measures (all rs greater than 0.75). Also, subjective stress responses were highly correlated, when considering both levels during stress and reactivity (r = 0.97 and r = 0.85, respectively). Stress levels of catecholamines were correlated, but the change scores (reactivity) were unrelated. 3. The measurement error SD for heart rate was 2.6 and 3.0 beats/min for reactivity and stress levels, respectively. The corresponding SD for blood pressure ranged between 2.7 and 4.4 mmHg. Subjective stress experience showed an SD of a similar magnitude. The responses of plasma catecholamine concentrations were subject to considerable variability. 4. It is concluded that haemodynamic and subjective stress responses and stress levels during the mental arithmetic stress test show acceptable reproducibility and high test-retest correlations. However, stress-induced changes in venous plasma catecholamine concentrations show low reproducibility.

To study the effect of sex hormones on the hemostatic responses to stress, blood samples were collected before, during, and after 20 min of mental stress from 9 healthy, non-smoking female volunteers, examined in the follicular and luteal phase. Mental stress caused significant increases in heart rate, blood pressure, and plasma catecholamines. In addition, analysis of variance indicated significant changes of leukocyte count, hematocrit, fibrinogen, von Willebrand factor antigen, t-PA activity and antigen in response to the stress test. However, in contrast to a male group previously investigated, there were no significant changes in factor VII coagulant activity in either menstrual phase. Overall the responses were more pronounced in the luteal as compared to the follicular phase. The findings support the concept that both gender and physiological variations in female sex hormones may modulate hemostatic responses to psychosocial stress.

The effects of cholinergic blockade on haemodynamic reactivity to standardized mental stress has been studied in nine normotensive males during infusion of atropine (bolus dose 10 micrograms x kg-1 followed by a constant-rate infusion of 0.02 microgram x kg-1 x min-1) or placebo given in a randomized order on two different days. Partial cholinergic blockade increased resting heart rate by 25-30 beats per minute. The magnitude of the heart rate response to stress (reactivity) however was unaffected by the atropine infusion. Also, in four subjects who received a higher dose of atropine (approximately 1.8-1.9 mg), heart rate responses to stress were the same as during placebo infusion. Cholinergic blockade was associated with a small but prolonged increase in diastolic blood pressure. These findings suggest that parasympathetic withdrawal does not contribute to the tachycardia caused by mental arithmetic, and that the pattern of neurogenic activation may differ from that elicited during a classic defence-alarm reaction and by somatomotor activation.

1. The haemodynamic effects of hormonal changes during the menstrual cycle were examined in 11 normotensive women (age 20-46 years). The subjects were studied on days 2-8 (follicular phase) and days 18-26 (luteal phase) in a randomized order. A standardized mental stress test and a 24 h recording of ambulatory blood pressure and heart rate were performed. 2. Pre-stress resting levels of heart rate and blood pressure were similar during the two phases of the menstrual cycle. 3. During mental stress, the heart rate response was significantly greater during the luteal phase than during the follicular phase (14.7 versus 9.7 beats/min; P less than 0.05). 4. Blood pressure, plasma catecholamine concentrations and subjective stress experience increased significantly in response to stress, without any significant differences between the two phases. 5. During 24 h ambulatory monitoring, higher levels of systolic blood pressure and heart rate were observed in the luteal phase than in the follicular phase (P less than 0.005 and P less than 0.0001, respectively). 6. These data indicate that cyclic variations in female sex hormones not only affect systolic blood pressure and heart rate, but also alter the haemodynamic responses to psychosocial stress.

To determine the importance of emotional stress for relative polycythaemia, we studied 11 subjects with the Type A and 11 subjects with the Type B behaviour patterns during short-term mental stress. All subjects were healthy, normotensive non-smoking young males aged 20-34 yr. without any medication. During rest there were no significant differences in heart rate, blood pressure, or plasma catecholamines between the two groups, but the A-group had significantly higher haemoglobin concentration (147 vs 140 g/l; p less than 0.005) and haematocrit (43.8 vs 42.1%: p = 0.05) than the B-group. In the whole group, there was a positive correlation between resting diastolic blood pressure and haemoglobin concentration (r = 0.53; p less than 0.05). In response to 10 min of mental arithmetic, haematocrit, haemoglobin and erythrocyte count rose approximately 2% (p less than 0.001 throughout). The stress-induced changes were not significantly different between the A- and B-groups. It is concluded that mild relative polycythaemia could be induced by acute emotional stress. In subjects with the Type A behaviour pattern a slight haemoconcentration is present already at rest, which further increases during stress.

To study the effects of standardized mental stress (arithmetic and the Stroop color word test) on plasma coagulation and fibrinolysis, blood samples were obtained before, during, and after 20 minutes of mental stress from 10 healthy, non-smoking young males aged 22 to 30 years. Reactions were compared with those observed during physical exercise and infusion of adrenaline. Both von Willebrand factor antigen and factor VIII coagulant activity increased significantly in response to mental stress (95 +/- 28 vs 123 +/- 56%; p less than 0.05 and 125 +/- 54 vs 217 +/- 170%; p less than 0.05, respectively). There was also a significant increase of factor VII coagulant activity (86 +/- 31 vs 108 +/- 51%; p less than 0.05). Furthermore, mental stress caused an activation of the fibrinolytic system with an elevation of tissue plasminogen activator activity and tissue plasminogen activator antigen (0.80 +/- 0.48 vs 1.23 +/- 0.96 IU/ml; p = 0.076 and 4.38 +/- 1.87 vs 5.78 +/- 2.58 IU/ml; p less than 0.01). Fibrinogen concentration increased during stress (1.95 +/- 0.29 vs 2.11 +/- 0.27 g/l; p less than 0.05). Similar but more pronounced responses were observed during exercise and adrenaline infusion. Parallel to the increases in coagulation and fibrinolytic factors there were significant increases in heart rate, and systolic and diastolic blood pressure. It is concluded that mental stress has significant effects on plasma coagulation and fibrinolysis, and that it could thus affect important risk factors for cardiovascular disease.

To study haematological effects of emotional stress, blood samples were obtained from 29 healthy, normotensive, non-smoking males aged 20-34 years before, during and after 10 min of mental arithmetic. There were significant increases in peripheral blood cell count, haemoglobin concentration, and haematocrit in response to mental stress. Parallel to these changes significant increases in heart rate, and systolic and diastolic blood pressure were observed. The relative increments of leucocyte (8%) and platelet (3.5%) count were significantly higher than the increase in haemoglobin concentration (2%). There was a significant positive correlation between the blood pressure increase and the mobilization of leucocytes, whereas the increase in erythrocyte count, haemoglobin concentration, and haematocrit showed significant positive correlations with heart rate reactivity. It is concluded that mental stress causes an increase in leucocyte and platelet count that could not solely be accounted for by the concurrent haemoconcentration.