Haemodynamic Responses during Experimental Emotional Stress and Physical Exercise in Hypertensive and Normotensive Patients J.J. GROEN, B. HANSEN, J.M. HERMANN, N. SCHAFER, T.H. SCHMIDT, K.H. SELBMANN, Th. V. UEXKULL and P. WECKMANN Depurtments o f Psychosomatics and Internal Medicine and Pediatrics, University of Ulm, Ulm (G.F. R.) and Afdeling Psychobiologie, Jelgersrnakliniek, Leyden University, Oegstgeest (The Netherlands)
INTRODUCTION The etiology and pathogenesis of essential hypertension are still largely unknown. Among the hypotheses which have been proposed, the psychosomatic theory regards the condition as a quantitative exaggeration (in time and intensity) of a physiological response of the circulation to certain environmental situations, which have a threatening, “stressful”, meaning for the individual (Groen et al., 1971). Von Uexkull and Wick (1962) have described such a transient “situational hypertension” in normal medical students during examinations and Wolf e t al. (1951, 1955) and Van der Valk (1957) have produced temporary rises in blood pressure in normal subjects by involving them in conversations which had an emotional meaning for them. Why such hypertensive responses in normal individuals are only temporary and of moderate magnitude, whereas the high blood pressure in patients with essential hypertension is persistent and mostly on a higher level, is explained by the psychosomatic theory partly by a hereditary propensity, partly by the fact that such patients appear t o live continually in what they perceive as a threatening situation, e.g., an unresolved conflict with their marriage partner. However, more information is needed about the state of the circulation during such periods of transient situational hypertension, compared with essential hypertension, before it is justified t o assume that essential hypertension is indeed a permanent o r chronic form of situational hypertension. In established essential hypertension the high blood pressure is associated with high peripheral vascular resistance and a normal or even low cardiac output. This is in contrast to, e.g., the high blood pressure which occurs during physical exercise, which is associated with a diminished peripheral vascular resistance and an increased cardiac output. In the investigation to be reported we have tried to test whether the high blood pressure in situational hypertension is part of the first described “hypertonic” circulatory pattern, as occurs in essential hypertension or part of the “hyperkinetic” pattern, as occurs during exercise. For this purpose we have subjected patients during cardiac catheterisation to an emotional interview aimed t o produce situational hypertension and have compared the effects on relevant parameters of the circulation with the effects of physical exercise.
302 We have examined both normotensive and hypertensive patients because, if the psychosomatic hypothesis that essential hypertension is not a separate disease but only an “exaggeration in intensity and duration” of situational hypertension is correct, it can be predicted that both during physical exercise and emotional stress the behaviour of the blood pressure and the associated parameters of the circulation will be essentially the same (with only quantitative differences) in normotensive and in hypertensive subjects, METHODS The following parameters were measured : (1)arterial blood pressure measured directly in the aorta (blood pressure transducers by F. Liechti AG, Bern); (2) right auricular pressure (idem); (3) cardiac output by the thermodilution method (Slaama and Piper) (HZV-Gerat, Fa. Fischer Typ HZV BN 6560); (4)heart rate (ECG). The following parameters were calculated from the data obtained from these measurements: (1)mean arterial pressure (by automatic integration); (2 mean right auricular pressure (by automatic integration); (3) cardiac index (= cardiac output/body surface); (4)stroke volume index (= cardiac output/heart rate x body surface); (5) index of the peripheral vascular resistance = [(mean arterial eressure - mean auricular pressure) x 60 x 13321 /(cardiac output x body surface). PROCEDURE No drugs were administered before or during the test procedures. The parameters were determined during the following experimental conditions: (1) The patients were instructed about the procedure, asked t o lie down comfortably on the couch, after which the probe and catheters were introduced, the adjustments for the measurements made and the apparatus standardised. During the next period of 15-20 min, measurements of the parameters were carried out in 2-5 min intervals, till a steady state was reached; the last 5 measurements (1-5) were used for the calculation. As the investigations took place in a laboratory situation which can be regarded as by itself emotionally stressing, we do not consider it justified t o designate the situation which preceded the other experimental conditions as “rest” or “standard” but prefer to name the period during which measurements 1-5 were made, the “expectancy phase”. Depending on a randomization programme, the examinations proceeded with either exercise or interview. (2) For the exercise test a bicycle ergometer was fixed t o the couch and the feet of the patient strapped to the pedals. During the test the patient “rode” the bicycle (remaining in the supine position) against a workload of respectively 40, 60 and 80 W d u r h g periods of 4 min successively. Measurements 6-11 were carried out at 2 min intervals in the middle and at
303 the end of every period. After the test followed a recuperation period of 1 5 min with measurements 12-17 carried out after 1, 2, 4, 6, 10 and 1 5 min. Three severely hypertensives and one normotensive patient did not go beyond 60 W during the exercise test. ( 3 ) Interview. The patients were subjected t o a programmed interview about their previous and present life situations, especially their relations to the keyfigures in their family and their work. The interview lasted about 12-18 min, depending on the duration of the patients’ replies. During the interview the following subjects were dealt with, while measurements 18-27 were made every 1 or 2 min: (a) Explanation of the aim of the examination, viz. t o find out more about the cause of the hypertension or, in the case of the normotensive patients, of their symptoms. (b) Asking the patient about his symptoms and whether he knew o r suspected the cause of these. (c) Questions about his work, his status in the job, his relationships with his boss and colleagues, whether he liked the work, whether it involved him in conflicts, whether it gave him satisfaction o r disappointed him. What were his prospects in his present job? (d) Questions about the family, relationships with parents in the past and present, if married about relationships with wife or husband, both in general and sexually. Whether he loved her and she loved him, whether the marriage had brought the patient the happiness he or she had expected from it and whether he (she) believed that the partner had found happiness in the marriage. The relationship to their children and t o the parents of the marriage partner. (e) Questions about hobbies, belonging t o societies, political and religious affiliations, ideas and problems. (f) Information about what the examination had shown up t o now and expression of the hope for a favourable outcome of the treatment. The interview was followed by a recuperation phase of 4 min at the end of which measurement 28 was made.
SUBJECTS Eleven patients with essential hypertension (7 males, 4 females) aged 27-45, in whom cardiac catheterisation was carried out in the context of extensive examinations t o find out the nature of their hypertension. Eleven normotensive patients ( 5 males, 6 females) aged 18-56, in whom for medical reasons cardiac catheterisation was performed but in whom n o organic pathology was established. Several of them were finally diagnosed as “neurovegetative vasolability ”. There were no significant differences in age or sex between the two groups. All hypertensive patients, besides fulfilling the clinical criteria of essential hypertension, had averaged systolic pressures above 158 mm Hg and diastolic pressures of above 9 5 during the first phase of the examination; the normotensive patients had averaged systolic and diastolic pressures below 150 and 95 mm Hg. There were no serious impairments of cardiac or renal function in the patients of either group.
304 RESULTS Fig. 1 presents the curves of the averaged measurements of the 7 parameters in the hypertensive and normotensive groups. The measurements during the expectancy phase, physical exercise followed by recuperation phase and interview, are given in this sequence, although they were obtained on the subjects in a randomized order. The figure also presents the behaviour of the circulation during some other experimental conditions (looking at pictures of parents and marriage partner, pressing a handergometer) which will not be discussed in this paper. During physical exercise both hypertensive and normotensive patients react with an increase in systolic and diastolic blood pressure. The pressures of the normotensive patients increased further with each increase in work load, the pressures of the hypertensive patients reached a maximum at 60 W, because some of the hypertensive patients had to stop the test a t this stage. The resistance index decreased continually during the exercise especially in the hypertensive patients, so that towards the end of the exercise it even approached the non-exercise values of the normotensive patients. Furthermore, it is interesting that while the normotensive patients regained their previous resistance values very quickly during recuperation, the resistance of the hypertensive patients rose more slowly and remained lower for the full 15 min of the recuperation phase. (This may illustrate a possible beneficial effect of physical exercise on the circulation in hypertensive patients.) Throughout the exercise test the cardiac index and the pulse rate increased continually and equally in both groups; the stroke volume index also increased, although less pronounced, in both groups. The right auricular pressure increased a few millimeters during the beginning of the exercise in both groups; toward the end of the test it was back t o the “expectancy” values. It was lowest during the recuperation period. During the interview both groups showed a marked increase in systolic and diastolic blood pressure. The average pulse rate was somewhat higher than during the expectancy phase in both groups. The cardiac index was somewhat higher, the stroke volume index about the same as in the expectancy phase; the resistance index was somewhat higher. In general, whereas both during exercise and interview the blood pressures were high, this was accompanied during the exercise by a large increase in cardiac output and low peripheral resistance, during the interview by small rises in both cardiac output and peripheral resistance. This pattern was the same in both groups. Fig. 2 summarizes the behaviour of the three main parameters of the circulation (mean blood pressure, cardiac output and peripheral resistance) in the two experimental conditions, exercise and interview, for all subjects. On the left of the figure are illustrated the effects of physical exercise. All subjects show a marked increase in cardiac output, a decrease in peripheral resistance and a moderate increase in mean blood pressure. There is no difference in the behaviour of the parameters between the two groups. On the right of the figure the effects are shown of the interview. It will be seen that there is a much smaller increase and in some cases even a decrease in cardiac output. There is a marked increase in mean blood pressure and, in the majority of cases, an
305 increase in peripheral resistance. Here again there is no obvious difference in circulatory behaviour between the groups. Thus the circulatory reaction pattern under an emotional stress is markedly different compared t o that during exercise : (1) During physical activity the circulatory reaction is characterised in all cases by an increase in arterial pressure with an increase in heart rate and cardiac output and a decrease in vascular resistance (hyperkinetic reaction).
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2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 4 0 42 MEASUREMENT N O .
Fig. 1. Averaged values of t h e circulation parameters of 11 normotensive (0-0, 11 hypertensive patients (0-0,E ) during all investigative procedures.
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Fig. 2. The percentual changes of the mean arterial pressure, peripheral vascular resistance index and cardiac index of the hypertensive and normotensive patients during the exercise test and t h e interview, Parameters of hypertensives (fat lines): w, during exercise; u , during interview. Parameters of normotensives (thin lines): 0 , during exercise; 0,during interview.
(2) Under the emotional interview the circulation reacts with an increase in systolic and diastolic blood pressure and, in 15 of the 22 cases, with an increase in vascular resistance, with smaller changes in pulse rate and cardiac output
(predominantly hypertonic reaction).
The hypertensive patients did not differ fundamentally, only in some respects quantitatively, from the normotensive patients in their circulatory behaviour during both experimental conditions. DISCUSSION The finding that the behaviour of the circulation under the experimental conditions was only quantitatively different in hypertensive and normotensive patients confirms Pickering's thesis (1968, 1974) that so-called essential hypertension is only the tail-end of a skewed distribution curve of the blood pressure in the population. This concept is also part of the psychosomatic theory which holds that the level of regulation of the blood pressure is higher
307 in these patients because they experience their psychosocial environment (family and work situation) as threatening. This hypothesis was supported by the finding (like by many others) that normotensive patients also develop a high blood pressure during a stressful “threatening” interview and above all by the demonstration that the mechanism of their experimentally induced situational hypertension is the same as that of the permanently raised blood pressure in hypertensive patients, viz., a rise in peripheral vascular resistance with relatively minor increases in cardiac output. Another observation also supports this hypothesis. During the expectancy phase, before the beginning of the tests, the average blood pressure in the hypertensives was significantly higher than during the recuperation phase after physical exercise, whereas in the normotensives this was just the reverse. This might indicate that lying down quietly on a couch during an experimental situation was experienced by the hypertensives as more stressful (“threatening”) than by the normotensive patients, although they gave no verbal or motoric signal of being apprehensive. Our findings are in agreement of those of Brod et al. (1959,1970) who also examined the circulation of normotensive and hypertensive patients during emotional stress and exercise. However they used an “unspecific” psychic stress, mental arithmetics which had t o be carried out t o the beat of a metronome, at a rate with which the subject was unable to cope. They also found that all normal subjects reacted by a rise in mean blood pressure, which in the majority was caused by a rise in peripheral vascular resistance, and only minor increases in cardiac output, in other words, by the circulation pattern which is characteristic for the permanent situation in essential hypertension. Our subjects showed this pattern when they were asked questions about their family and work situation. This makes our experiment a better test of the psychosomatic hypothesis that patients with essential hypertension experience their relations with marriage partners and keyfigures in the work situation as continuously stressful and react t o this by inhibited aggression and the circulatory pattern that goes with this.
SUMMARY Heart rate, intra-aortal blood pressure, cardiac output and peripheral vascular resistance were determined in 11 hypertensive and 11 normotensive subjects during exercise up t o 80 W on a bicycle ergometer and a semi-standardized interview concerning personal life situations. Blood pressure increased during both conditions. During exercise this was associated with increases in heart rate and cardiac output and a decrease in peripheral resistance (hyperkinetic reaction). During the emotional interview the heart rate and cardiac output also increased but less so and in 1 5 of 22 cases the peripheral resistance rose (predominantly hypertonic reaction). There was no fundamental but only a quantitative difference in the circulatory responses between the two groups. These results support the hypothesis that essential hypertension is not a disease “sui generis” but a quantitative exaggeration of the same processes which regulate blood pressure in different situations in normotensive individuals. The
life situations which were discussed during the experimental interview which produced a rise in blood pressure and peripheral resistance of short duration, may have played a role in the pathogenesis of the persistently increased blood pressure in the patients with essential hypertension.
REFERENCES Brod, J., Fencl, V., Heyl, Z. and Jirke, J. (1959) Circulatory changes underlying blood pressure elevations during acute emotional stress (mental arithmetic) in norinotensive and hypertensive subjects. Clin. Sci., 18: 269-279. Brod, J. (1970) Haemodynamics and emotional stress. In Psychosomatics in Essential Hypertension, M. Koster, H. Musaph and P. Visser (Eds.), Karger, Basel, pp. 13-33. , Groen, J.J., Van der Valk, J.M., Welner, A . and Ben-Ishay, D. (1971) Psychobiological factors in the pathogenesis of essential hypertension. Psychother. Psychosom., 1 9 : 1-26. Pickering, G.W. (1968) High Blood Pressure, 2nd ed., Churchill, London. Pickering, G.W. (1974) Hypertension, Causes, Consequences, Management, ChurchillLivingstone, Edinburgh. Van der Valk, J.M. (1957) Blood pressure changes under emotional influences in patients with essential hypertension and control subjects. J. p s y c h o s o m . Res., 2 : 134-146. Von Uexkull, Th. und Wick, E. (1962) Die Situationshypertonie. Arch. Kreis1.-Forsch., 39: 236-27 1. Wolf, S. and Wolff, H.G. (1951) Experimental evidence relating life stress t o essential hypertension. In Hypertension, a S y m p o s i u m , E.T. Bell (Ed.), Univ. of Minnesota Press, Minneapolis, pp. 288-330. Wolf, S., Cardon, P.V., Shepard, E.M. and Wolff, H.G. (1955) Life Stress and Essential Hypertension, Williams and Wilkins, Baltimore, Md.
INTRODUCTION The etiology and pathogenesis of essential hypertension are still largely unknown. Among the hypotheses which have been proposed, the psychosomatic theory regards the condition as a quantitative exaggeration (in time and intensity) of a physiological response of the circulation to certain environmental situations, which have a threatening, “stressful”, meaning for the individual (Groen et al., 1971). Von Uexkull and Wick (1962) have described such a transient “situational hypertension” in normal medical students during examinations and Wolf e t al. (1951, 1955) and Van der Valk (1957) have produced temporary rises in blood pressure in normal subjects by involving them in conversations which had an emotional meaning for them. Why such hypertensive responses in normal individuals are only temporary and of moderate magnitude, whereas the high blood pressure in patients with essential hypertension is persistent and mostly on a higher level, is explained by the psychosomatic theory partly by a hereditary propensity, partly by the fact that such patients appear t o live continually in what they perceive as a threatening situation, e.g., an unresolved conflict with their marriage partner. However, more information is needed about the state of the circulation during such periods of transient situational hypertension, compared with essential hypertension, before it is justified t o assume that essential hypertension is indeed a permanent o r chronic form of situational hypertension. In established essential hypertension the high blood pressure is associated with high peripheral vascular resistance and a normal or even low cardiac output. This is in contrast to, e.g., the high blood pressure which occurs during physical exercise, which is associated with a diminished peripheral vascular resistance and an increased cardiac output. In the investigation to be reported we have tried to test whether the high blood pressure in situational hypertension is part of the first described “hypertonic” circulatory pattern, as occurs in essential hypertension or part of the “hyperkinetic” pattern, as occurs during exercise. For this purpose we have subjected patients during cardiac catheterisation to an emotional interview aimed t o produce situational hypertension and have compared the effects on relevant parameters of the circulation with the effects of physical exercise.
302 We have examined both normotensive and hypertensive patients because, if the psychosomatic hypothesis that essential hypertension is not a separate disease but only an “exaggeration in intensity and duration” of situational hypertension is correct, it can be predicted that both during physical exercise and emotional stress the behaviour of the blood pressure and the associated parameters of the circulation will be essentially the same (with only quantitative differences) in normotensive and in hypertensive subjects, METHODS The following parameters were measured : (1)arterial blood pressure measured directly in the aorta (blood pressure transducers by F. Liechti AG, Bern); (2) right auricular pressure (idem); (3) cardiac output by the thermodilution method (Slaama and Piper) (HZV-Gerat, Fa. Fischer Typ HZV BN 6560); (4)heart rate (ECG). The following parameters were calculated from the data obtained from these measurements: (1)mean arterial pressure (by automatic integration); (2 mean right auricular pressure (by automatic integration); (3) cardiac index (= cardiac output/body surface); (4)stroke volume index (= cardiac output/heart rate x body surface); (5) index of the peripheral vascular resistance = [(mean arterial eressure - mean auricular pressure) x 60 x 13321 /(cardiac output x body surface). PROCEDURE No drugs were administered before or during the test procedures. The parameters were determined during the following experimental conditions: (1) The patients were instructed about the procedure, asked t o lie down comfortably on the couch, after which the probe and catheters were introduced, the adjustments for the measurements made and the apparatus standardised. During the next period of 15-20 min, measurements of the parameters were carried out in 2-5 min intervals, till a steady state was reached; the last 5 measurements (1-5) were used for the calculation. As the investigations took place in a laboratory situation which can be regarded as by itself emotionally stressing, we do not consider it justified t o designate the situation which preceded the other experimental conditions as “rest” or “standard” but prefer to name the period during which measurements 1-5 were made, the “expectancy phase”. Depending on a randomization programme, the examinations proceeded with either exercise or interview. (2) For the exercise test a bicycle ergometer was fixed t o the couch and the feet of the patient strapped to the pedals. During the test the patient “rode” the bicycle (remaining in the supine position) against a workload of respectively 40, 60 and 80 W d u r h g periods of 4 min successively. Measurements 6-11 were carried out at 2 min intervals in the middle and at
303 the end of every period. After the test followed a recuperation period of 1 5 min with measurements 12-17 carried out after 1, 2, 4, 6, 10 and 1 5 min. Three severely hypertensives and one normotensive patient did not go beyond 60 W during the exercise test. ( 3 ) Interview. The patients were subjected t o a programmed interview about their previous and present life situations, especially their relations to the keyfigures in their family and their work. The interview lasted about 12-18 min, depending on the duration of the patients’ replies. During the interview the following subjects were dealt with, while measurements 18-27 were made every 1 or 2 min: (a) Explanation of the aim of the examination, viz. t o find out more about the cause of the hypertension or, in the case of the normotensive patients, of their symptoms. (b) Asking the patient about his symptoms and whether he knew o r suspected the cause of these. (c) Questions about his work, his status in the job, his relationships with his boss and colleagues, whether he liked the work, whether it involved him in conflicts, whether it gave him satisfaction o r disappointed him. What were his prospects in his present job? (d) Questions about the family, relationships with parents in the past and present, if married about relationships with wife or husband, both in general and sexually. Whether he loved her and she loved him, whether the marriage had brought the patient the happiness he or she had expected from it and whether he (she) believed that the partner had found happiness in the marriage. The relationship to their children and t o the parents of the marriage partner. (e) Questions about hobbies, belonging t o societies, political and religious affiliations, ideas and problems. (f) Information about what the examination had shown up t o now and expression of the hope for a favourable outcome of the treatment. The interview was followed by a recuperation phase of 4 min at the end of which measurement 28 was made.
SUBJECTS Eleven patients with essential hypertension (7 males, 4 females) aged 27-45, in whom cardiac catheterisation was carried out in the context of extensive examinations t o find out the nature of their hypertension. Eleven normotensive patients ( 5 males, 6 females) aged 18-56, in whom for medical reasons cardiac catheterisation was performed but in whom n o organic pathology was established. Several of them were finally diagnosed as “neurovegetative vasolability ”. There were no significant differences in age or sex between the two groups. All hypertensive patients, besides fulfilling the clinical criteria of essential hypertension, had averaged systolic pressures above 158 mm Hg and diastolic pressures of above 9 5 during the first phase of the examination; the normotensive patients had averaged systolic and diastolic pressures below 150 and 95 mm Hg. There were no serious impairments of cardiac or renal function in the patients of either group.
304 RESULTS Fig. 1 presents the curves of the averaged measurements of the 7 parameters in the hypertensive and normotensive groups. The measurements during the expectancy phase, physical exercise followed by recuperation phase and interview, are given in this sequence, although they were obtained on the subjects in a randomized order. The figure also presents the behaviour of the circulation during some other experimental conditions (looking at pictures of parents and marriage partner, pressing a handergometer) which will not be discussed in this paper. During physical exercise both hypertensive and normotensive patients react with an increase in systolic and diastolic blood pressure. The pressures of the normotensive patients increased further with each increase in work load, the pressures of the hypertensive patients reached a maximum at 60 W, because some of the hypertensive patients had to stop the test a t this stage. The resistance index decreased continually during the exercise especially in the hypertensive patients, so that towards the end of the exercise it even approached the non-exercise values of the normotensive patients. Furthermore, it is interesting that while the normotensive patients regained their previous resistance values very quickly during recuperation, the resistance of the hypertensive patients rose more slowly and remained lower for the full 15 min of the recuperation phase. (This may illustrate a possible beneficial effect of physical exercise on the circulation in hypertensive patients.) Throughout the exercise test the cardiac index and the pulse rate increased continually and equally in both groups; the stroke volume index also increased, although less pronounced, in both groups. The right auricular pressure increased a few millimeters during the beginning of the exercise in both groups; toward the end of the test it was back t o the “expectancy” values. It was lowest during the recuperation period. During the interview both groups showed a marked increase in systolic and diastolic blood pressure. The average pulse rate was somewhat higher than during the expectancy phase in both groups. The cardiac index was somewhat higher, the stroke volume index about the same as in the expectancy phase; the resistance index was somewhat higher. In general, whereas both during exercise and interview the blood pressures were high, this was accompanied during the exercise by a large increase in cardiac output and low peripheral resistance, during the interview by small rises in both cardiac output and peripheral resistance. This pattern was the same in both groups. Fig. 2 summarizes the behaviour of the three main parameters of the circulation (mean blood pressure, cardiac output and peripheral resistance) in the two experimental conditions, exercise and interview, for all subjects. On the left of the figure are illustrated the effects of physical exercise. All subjects show a marked increase in cardiac output, a decrease in peripheral resistance and a moderate increase in mean blood pressure. There is no difference in the behaviour of the parameters between the two groups. On the right of the figure the effects are shown of the interview. It will be seen that there is a much smaller increase and in some cases even a decrease in cardiac output. There is a marked increase in mean blood pressure and, in the majority of cases, an
305 increase in peripheral resistance. Here again there is no obvious difference in circulatory behaviour between the groups. Thus the circulatory reaction pattern under an emotional stress is markedly different compared t o that during exercise : (1) During physical activity the circulatory reaction is characterised in all cases by an increase in arterial pressure with an increase in heart rate and cardiac output and a decrease in vascular resistance (hyperkinetic reaction).
110 120 HR/min
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180
eorta
160 140
mmHg 120
100
80
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60
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1 1 1 I I 1 I I 1 I 1 I 1 1 I I I I I 1 I 1 1 1 I
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 4 0 42 MEASUREMENT N O .
Fig. 1. Averaged values of t h e circulation parameters of 11 normotensive (0-0, 11 hypertensive patients (0-0,E ) during all investigative procedures.
) and
306 PHYSICAL EXERCISE (60 Watt)
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Fig. 2. The percentual changes of the mean arterial pressure, peripheral vascular resistance index and cardiac index of the hypertensive and normotensive patients during the exercise test and t h e interview, Parameters of hypertensives (fat lines): w, during exercise; u , during interview. Parameters of normotensives (thin lines): 0 , during exercise; 0,during interview.
(2) Under the emotional interview the circulation reacts with an increase in systolic and diastolic blood pressure and, in 15 of the 22 cases, with an increase in vascular resistance, with smaller changes in pulse rate and cardiac output
(predominantly hypertonic reaction).
The hypertensive patients did not differ fundamentally, only in some respects quantitatively, from the normotensive patients in their circulatory behaviour during both experimental conditions. DISCUSSION The finding that the behaviour of the circulation under the experimental conditions was only quantitatively different in hypertensive and normotensive patients confirms Pickering's thesis (1968, 1974) that so-called essential hypertension is only the tail-end of a skewed distribution curve of the blood pressure in the population. This concept is also part of the psychosomatic theory which holds that the level of regulation of the blood pressure is higher
307 in these patients because they experience their psychosocial environment (family and work situation) as threatening. This hypothesis was supported by the finding (like by many others) that normotensive patients also develop a high blood pressure during a stressful “threatening” interview and above all by the demonstration that the mechanism of their experimentally induced situational hypertension is the same as that of the permanently raised blood pressure in hypertensive patients, viz., a rise in peripheral vascular resistance with relatively minor increases in cardiac output. Another observation also supports this hypothesis. During the expectancy phase, before the beginning of the tests, the average blood pressure in the hypertensives was significantly higher than during the recuperation phase after physical exercise, whereas in the normotensives this was just the reverse. This might indicate that lying down quietly on a couch during an experimental situation was experienced by the hypertensives as more stressful (“threatening”) than by the normotensive patients, although they gave no verbal or motoric signal of being apprehensive. Our findings are in agreement of those of Brod et al. (1959,1970) who also examined the circulation of normotensive and hypertensive patients during emotional stress and exercise. However they used an “unspecific” psychic stress, mental arithmetics which had t o be carried out t o the beat of a metronome, at a rate with which the subject was unable to cope. They also found that all normal subjects reacted by a rise in mean blood pressure, which in the majority was caused by a rise in peripheral vascular resistance, and only minor increases in cardiac output, in other words, by the circulation pattern which is characteristic for the permanent situation in essential hypertension. Our subjects showed this pattern when they were asked questions about their family and work situation. This makes our experiment a better test of the psychosomatic hypothesis that patients with essential hypertension experience their relations with marriage partners and keyfigures in the work situation as continuously stressful and react t o this by inhibited aggression and the circulatory pattern that goes with this.
SUMMARY Heart rate, intra-aortal blood pressure, cardiac output and peripheral vascular resistance were determined in 11 hypertensive and 11 normotensive subjects during exercise up t o 80 W on a bicycle ergometer and a semi-standardized interview concerning personal life situations. Blood pressure increased during both conditions. During exercise this was associated with increases in heart rate and cardiac output and a decrease in peripheral resistance (hyperkinetic reaction). During the emotional interview the heart rate and cardiac output also increased but less so and in 1 5 of 22 cases the peripheral resistance rose (predominantly hypertonic reaction). There was no fundamental but only a quantitative difference in the circulatory responses between the two groups. These results support the hypothesis that essential hypertension is not a disease “sui generis” but a quantitative exaggeration of the same processes which regulate blood pressure in different situations in normotensive individuals. The
life situations which were discussed during the experimental interview which produced a rise in blood pressure and peripheral resistance of short duration, may have played a role in the pathogenesis of the persistently increased blood pressure in the patients with essential hypertension.
REFERENCES Brod, J., Fencl, V., Heyl, Z. and Jirke, J. (1959) Circulatory changes underlying blood pressure elevations during acute emotional stress (mental arithmetic) in norinotensive and hypertensive subjects. Clin. Sci., 18: 269-279. Brod, J. (1970) Haemodynamics and emotional stress. In Psychosomatics in Essential Hypertension, M. Koster, H. Musaph and P. Visser (Eds.), Karger, Basel, pp. 13-33. , Groen, J.J., Van der Valk, J.M., Welner, A . and Ben-Ishay, D. (1971) Psychobiological factors in the pathogenesis of essential hypertension. Psychother. Psychosom., 1 9 : 1-26. Pickering, G.W. (1968) High Blood Pressure, 2nd ed., Churchill, London. Pickering, G.W. (1974) Hypertension, Causes, Consequences, Management, ChurchillLivingstone, Edinburgh. Van der Valk, J.M. (1957) Blood pressure changes under emotional influences in patients with essential hypertension and control subjects. J. p s y c h o s o m . Res., 2 : 134-146. Von Uexkull, Th. und Wick, E. (1962) Die Situationshypertonie. Arch. Kreis1.-Forsch., 39: 236-27 1. Wolf, S. and Wolff, H.G. (1951) Experimental evidence relating life stress t o essential hypertension. In Hypertension, a S y m p o s i u m , E.T. Bell (Ed.), Univ. of Minnesota Press, Minneapolis, pp. 288-330. Wolf, S., Cardon, P.V., Shepard, E.M. and Wolff, H.G. (1955) Life Stress and Essential Hypertension, Williams and Wilkins, Baltimore, Md.
