This article was downloaded by: [University of Edinburgh] On: 21 October 2014, At: 01:59 Publisher: Routledge Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
Journal of Sex & Marital Therapy Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/usmt20
Some aspects and implications of coital physiology Cyril A. Fox MD
a b
a
Unit of Obstetrics, Gynaecology and Reproductive Psychology , St. Bartholomew's Hospital Medical College University of London , England b
Department of Obstetrics and Gynaecology , St. Bartholomew's Hospital Medical College University of London , England Published online: 14 Jan 2008.
To cite this article: Cyril A. Fox MD (1976) Some aspects and implications of coital physiology, Journal of Sex & Marital Therapy, 2:3, 205-213, DOI: 10.1080/00926237608405323 To link to this article: http://dx.doi.org/10.1080/00926237608405323
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/termsand-conditions
Journal of Sex & Marital Therapy Vol. 2, No. 3, Fall 1976
Some Aspects and Implications of Coital Physiology
Downloaded by [University of Edinburgh] at 01:59 21 October 2014
Cyril A . Fox, MD
ABSTRACT: A review of some experiments in human coital physiology in the home setting considers their possible value to the sex therapist. Blood pressure changes are described in normal subjects with reference to their relevance in patients with heart disease or high blood pressure. Respiratory patterns and intravaginal and intrauterine pressure changes are described during coitus, and their significance in different types of female orgasm are discussed. It now appears that a specific deeply satisfying and terminative female orgasm is associated with a particular type of respiratory pattern and intrauterine pressure change. The use of radiotelemetry devices to measure pressure and pH changes during coitus makes home studies possible. Further projects and areas for future study are considered.
The new discipline of sex therapy is making rapid strides because of the sound basis laid by pioneering work in the United States. It is, therefore, very much as a disciple that I present a review of some experiments in coital physiology from the Old World. Prior to the publications of Kinsey et al.' and Masters and Johnson2 only a few isolated experiments were found in the literature, and only in the past decade have writers or editors of textbooks of human physiology added to the brief pages on coitus in their volumes. The serious student of sexology has the benefit of knowing that his work may add to insight not only in the areas of sexual malfunction and its attendant psychological trauma, but also in matters of fertility and infertility, contraception, and world population. It becomes obvious that the intimate nature of the sexual act and the inhibitions of the researcher and society have been the major factors holding back progress in such vital issues. I propose to deal with some of the progress that has been made, to examine its relevance, and to suggest pointers for future research. Apologies must be offered to readers familiar with much of this work previously p ~ b l i s h e d ,but ~ it is earnestly hoped that some will benefit from lesser publicized data and from the Dr. Fox is associated with the Williamson laboratory part of the Academic Unit of Obstetrics, Gynaceology and Reproductive Physiology, and the Department of Obstetrics and Gynaecology, St. Bartholomew's Hospital Medical College University of London, England.
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reappraisal. Perhaps a few will be persuaded t o launch their own studies, having been fired with the spirit of inquiry as the author was when the message came in the reverse direction some 10 years ago. I t is necessary to understand our philosophy at the Williamson Labroatory for we feel that coital experiments should be conducted in the subjects’ home and away from the laboratory setting. Indeed, it would be difficult to do otherwise in Europe. To this end we have specifically designed some rather sophisticated electronic equipment so that participants are minimally inconvenienced, observers are not present, and the intimacy and naturalness of the sexual act is (as far as possible) preserved. Unless otherwise stated, the data is represented in the form of continuous recordings and represented by photographs of the original tracings and not artists3 impressions.
R E VIEW A N D DISCUSSION OF COITAL EXPERIMENTS
Blood Pressure Three experiments dealing with the rise in blood pressur during natural coitus have been published. Fox and Fox4 showed a rise in systolic blood pressure from a resting level of 125 mm Hg t o a peak of 175 mm Hg at ejaculation in a male subject (see Figure I ) and a rise from 100 to 200 mm Hg in a female subject at orgasm. In both sexes the blood pressure fell precipitately after the climax to a slightly lower level than the resting value and the total time for the peak elevation was about 90 seconds. Bevan, Honour, ar.d Stott’ made direct arterial recordings in one male and found an increase of 35 mm Hg systolic pressure and of 10 mm Hg diastolic pressure during coitus. The average pressure while lying in bed before the act was 85/60, during the act 120/70, and at the climax 160/100,with a postorgasmic fall to 60/30. All readings were taken through an arterial catheter, and the experiment was performed in the subject’s home because of the ingenious design of the equipment. Further studies using the same method were reported from Oxford by Littler, Honour, and Sleight6 with six male and one female participants in their respective homes. They were all normotensive, and rises in systolic pressure of up to 100 mm Hg systolic and 48 mm Hg diastolic were noted. Heart rate was increased to about 160/minute. Thcse findings are of more than academic interest since patients may present for advice about sexual activity after a coronary thrombosis or hypertensives may wish to know whether they are at risk. Death during coitus is not unknown, and Professor Lundberg, a Swedish neurologist, has stated that he has seen 25 cases of subarachnoid hemorrhage that occurred during coitus,’ the majority being cxtramarital liasons. In an attempt to study substances that might lower blood pressure during intercourse and at the climax, we investigated the effect of the beta-blocking agent pro-
Cyril A . Fox
Downloaded by [University of Edinburgh] at 01:59 21 October 2014
240 200
1
20 7
280
I
::I, I
I
I
240
I
0
I
I
,
,
::[ 0
Minutes FIGURE 1
1 I
,
,
,
,
Minutee
FIGURE 2
pranolol.8 It was found that in normotcnsive subjects an oral dose of 160 mg, taken 1% hours before the event, was able t o reduce the expected rise in systolic blood pressure without affecting the quality or ease of attainment of the climax (Figure 2). Thus far there are no reported studies in the literature concerning hypertensive patients, We are about to embark on one such study in London using a new noninvasive continuous blood pressure recorder of greater sophistication and accuracy than our previous digital recorder. Hellerstein and Friedman' have produced the best work with patients (postcoronary); they asked the patients to record their own EKGs on a special tape recorder in their own homes during sexual activity and to return the tapes t o them for analysis. Hcllerstein and Friedman were able t o give some reassurance to their pateints through this "sexercise tolerance test." Nevertheless, a quarter of the patients with angina complained of chest pain during coitus. A leading article in the British M e d i c h Journal" has summed up current thinking on sexual activity in angina patients. This is a neglected area o f sex counseling because patients may be too timid or otherwise preoccupied t o ask their specialists, and little information is available t o the latter even if they were interested. The results is that patients may be happily discharged from hospitals only t o find later that they have worries about a return t o a normal sex life.
Respiratory Pat t ems Respiratory changes during sexual activity were studies by Bartlctt," who noted an increase in pulmonary ventilation. He found a respiratory rate of 60/ minute and a minute volume of 50l/minute at the climax, all compatible with modcratcly severe exercise. Whcn we repeated these experiments," using a
208
Journal of Sex and Marital Therapy
Ejaculation
Downloaded by [University of Edinburgh] at 01:59 21 October 2014
I
2
1
0
’
minutes
FIGURE 3
Benedict-Roth Spirometer to obtain tracings, we were struck by the different preclimax patterns in the two sexes (see Figures 3 and 4.1, for there was marked apnoea in the female tracing. Both sexes showed the well-known postorgasmic hyperventilation (not seen so well in Figure 4 but shown clearly in our original publication). The important point about Figure 4 is that there are obvious periods of breath holding that may have considerable significance in the nature of the female orgasm, both subjectively and objectively (see the next section on intrauterine pressure changes). In a fascinating novel, The Great Railway Bazaar about a train journey across Asia, Paul Theroux writes, “Your eyes get accustomed to the dark and you see the waitress is naked. Without warning she jumps onto a chair, pokes a cigarette into her vagina and lights it, puffing it by contracting her uterine lungs.” I feel sure that she does this by attempting inspiration against a closed epiglottis while tensing the abdomnal and pelvic muscles. Sccond
Female Orgasm
First Female Orgasm
i FIGURE 4
Cyril A . Fox
209
Downloaded by [University of Edinburgh] at 01:59 21 October 2014
Intravaginal and Intra-uterine Pressure Changes In order to investigate the effects of coitus upon intravaginal and intrauterine pressures, it was necessary to design equipment that could be used in the absence of observers and in the bedroom. The radiotelemetry capsules shown in Figure 5 fulfilled the requirements since they were small (25 mmX9mm), unobtrusive, and reasonably well tolerated and had no attached wires. Basically, the capsule is powered by a tiny mercury battery (as in a deaf aid ) and emits a signal the lrequcncy of which can be modulated by changes in pressure and pH, respectively. A special receiver has been designed to pick up this signal and convert it to a linear tracing. The only requirement is that the participant does not move out of the confines of a loop aerial (1% m diameter) that is placed beneath the sheet on the bed. It is the only link between the capsule and its receiver. It must be stressed that the capsule has no attached wires. The setup is such that the participant, capsule, and loop aerial can be in one room and the receiver and recorder in another room. Since the original pressure device had a diameter of 9 mm, it was necessary to dilate the cervix to place it in the uteriis for measurements to be made, but we overcame this
C
A FIGURE 5
Journal of Sex and Marital Therapy
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210
problem by using an antenna (Figure 5B) of 3 mm diameter, and this worked just as well. During ejaculation the intravaginal pressure fell to a negative value of -20 cm water, probably due to the separation of the walls of the vagina by the straining penis. During female orgasm the intravaginal pressure rose to +20cm water, but the intrauterine pressure, after an initial rise to +40 cm, fell sharply to -10 cm water (Figure 6). In earlier experiements’* it had fallen as low as -26 cm. Thus there was a pressure gradient between the vagina and uterus that may have some importance in the consideration of sperm transport. It is possible that the female orgasm actively accelerates the passage of spermatozoa between vagina and uterus. Certainly, with the pressure lower in the uterus than in the vagina conditions art‘ more favorable for the necessary journey. Furthermore, the type of orgasm associated with these pressure changes was of the deeply satisfying type described by Fox and Fox4 and designated by SingerI3 as a “uterine” orgasm. This classification of female orgasm by Singer into (a) vulval, (b) uterine, and (c) blended (vulval + uterine) has much to commend it. It is based on the physiological fact that the vulval orgasm, previously termed clitoral orgasm, while pleasurable is not deeply satisfying and nonterminative, whereas the uterine orgasm is deeply satisfying and is terminative. There is some evidence from our work on intrauterine pressure changes that a nonterminative orgasm produces less quantitative change, and this is equally so with respiratory patterns. Close inspection of Figure 6 will show that there are two female orgasms. In the first, which was not terminative, the pressure rose steeply but did not drop below the base line to a negative F.O.
E
F. a
I -ve press -I0 -20
t FIGURE 6
Downloaded by [University of Edinburgh] at 01:59 21 October 2014
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211
pressure. The second orgasm was terminative and deeply satisfying; here we find a fall to a negative pressure within the uterus. The same effect with the two types of orgasm can be seen in our original publication (text figure 4a) using the unmodified pressure capsule.12 We believe that this is the true basis of the “uterine” orgasm and that the changes described occur only with this form of orgasm and with the particular breathing pattern described. It is illuminating t o find that what is so satisfactory subjectively is also capable of physiological insight and explanation. We dare not talk of the “best type of orgasm,” but it is gratifying to find that we have investigated one type that gives profound release and is propitious for conception. The female, of course, differs from the male in being able to experience repeated orgasms since there is no refractory period for the former. This lack of refractory period in the female does not necessarily mean that multiple orgasms are more pleasurable; they may indeed by a cause of concern because of the lack of release. It is probably that multiple orgasms are vulval, and if a woman complains of lack of satisfaction, conversion to uterine or blended orgasm may be achieved by counseling using the above physiological explanation or by suggesting deep penetration by the male.
pH Changes Within the Vagina Using a radiotelemetry pH capsule (Figure 5C), Fox, Meldrum, and WatsonI4 measured changes within the vagina and upon arrival of semen during coitus. The capsule was well tolerated, for it resembled a small pessary and was placed high in the vagina near the cervix where semen was likely to be ejaculated. The surprising finding was the rapid buffering of seminal fluid, for in the normally fertile male the pH of the seminal fluid was hardly affected. To put it another way, the vaginal pH (4)changed to pH7 (that of seminal fluid) within 8 seconds of ejaculation. It seems unlikely, therefore, that the vagina is a “hostile environment,’ in the normal situation. In the case of infertile or subfertile males we found that vaginal pH did not rise about pH5.5, and it is known that spermatozoa are immobilized by a pH o f less than 6. Poor buffering power and low ejaculate volume contribute to infertility. When a normally fertile male had lowered his ejaculatory volume and his sperm count by repeated ejaculation (four times in 48 hours was sufficient), he buffered as poorly as an infertile man. Again, it is interesting to speculate that what is, subjectively, increasingly less pleasurable (repeated ejaculation) is also physiologically significant in terms of procreation. Masters and Johnson’ have alluded to the fact that several days abstinence gives a more pleasurable ejaculation, and this fact may be brought out in general counseling. For the subfertile it is vital that “trying hard” should be discouraged.
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PROSPECTS FOR FUTURE RESEARCH. The need for further research into blood pressure changes has been stressed so that clinicians may be in a position t o advise patients with angina, coronary thrombosis, or hypertension. On a wider scale, thought should be given t o the disabled who wish t o lead a normal sex life and to the elderly who are beset with problems. Further research into breathing patterns in association with intrauterine pressure studies may reveal more about the female orgasm. As the telemetry capsules becomc smaller, and we are now testing ones with a 7 mm diameter, it may be possible to position these devices so that two or three are used in situ t o measure gradients of pressure. Similarly, with the reduction in size o f the pH capsule it should be possible t o measure intrauterine pH during orgasm. We feel that it should be possible t o measure the time taken for sperm t o enter the uterus if seminal fluid is “labeled” by placing a strong buffer solution in the vagina (say at pH 8) and there is a telemetry capsule in the uterus. When the labeled semen at pH8 reaches the intrauterine device, this should register above the usual uterine pH of about 7.2. We await the technology for this experiment and are assured that it is almost available. We have previously reviewed hormonal changes during ~ o i t u s and , ~ further consideration appears elsewhere in this issue. The problem of sampling during coitus has been the major factor in limiting such studies. Some form of automatic sampler has been suggested, but for the present we must rely on medical. or paramedical participants who are prepared t o use an indwelling “butterfly” canulla. This can be kept in a vein for up to 24 hours without discomfort. It remains patent with the use of heparin-saline, and frequent sampling can be carried out even by the wearer of the canulla. With so many hormonal assays now available by radioimmunoassay, there is great scope for the sex physiologist.
REFERENCES 1. Kinsey AC, Pomeroy WB, Marin CE, Cebhard PH: Sexual Behavior in the Human Female. Philadelphia, Saunders, 1953. 2. Masters WH, Johnson VE: Human Sexual Response. Boston, Little, Brown, 1966. 3. Fox CA: Recent studies in human coital physiology. Clin Endoctinol Metabof 2:527-541, 1973. 4. Fox CA, Fox B: Blood pressure and respiratory patterns during human coitus. Reprod Fertil 19:405-415, 1969. 5. Bevan AT, Honour AJ, Stott FH: Direct arterial pressure recording in unrestricted man. Clin Sci 36:329-344, 1969. 6 . Littler WA, Honour AJ, Sleight P: Direct arterial pressure, heart rate and electrocardiogram during human coitusj. Reprod. FertiZ40:321-331, 1974. 7 . Lundberg P. Personal communication, 1974. a. Fox CA: Reduction in the rise of systolic blood pressure during human coitus by the betablocking agent propranolol. J Reprod Fertil 22:587-590, 1970. 9. Hellerstein HK, Friedman EH; Sexual activity and the post-coronary patient. Arch Intern Med 125:987-999, 1970.
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10. Coitus and coronaries. 3rMed J 1:414, 1976. 1 1 . Bartlett RJ; Physiologic responses during coitus. J Appl Physiol9:469472, 1956. 12. Fox CA, Wolff HS, Baker JA: Measurement of intra-vaginal and intra-uterine pressures during human coitus by radio-telemetry. J Reprod Fertil 22243-251, 1970. 13. Singer I: The Goals of Human Sexuality. New York,Norton, 1973, Chapter 3. 14. Fox CA, Meldrum SJ, Watson BW: Continuous measurement by vaginal pH during human coitus. J Reprod Fertil 33:69-75, 1973.
I
b..c.l
I
Journal of Sex & Marital Therapy Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/usmt20
Some aspects and implications of coital physiology Cyril A. Fox MD
a b
a
Unit of Obstetrics, Gynaecology and Reproductive Psychology , St. Bartholomew's Hospital Medical College University of London , England b
Department of Obstetrics and Gynaecology , St. Bartholomew's Hospital Medical College University of London , England Published online: 14 Jan 2008.
To cite this article: Cyril A. Fox MD (1976) Some aspects and implications of coital physiology, Journal of Sex & Marital Therapy, 2:3, 205-213, DOI: 10.1080/00926237608405323 To link to this article: http://dx.doi.org/10.1080/00926237608405323
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/termsand-conditions
Journal of Sex & Marital Therapy Vol. 2, No. 3, Fall 1976
Some Aspects and Implications of Coital Physiology
Downloaded by [University of Edinburgh] at 01:59 21 October 2014
Cyril A . Fox, MD
ABSTRACT: A review of some experiments in human coital physiology in the home setting considers their possible value to the sex therapist. Blood pressure changes are described in normal subjects with reference to their relevance in patients with heart disease or high blood pressure. Respiratory patterns and intravaginal and intrauterine pressure changes are described during coitus, and their significance in different types of female orgasm are discussed. It now appears that a specific deeply satisfying and terminative female orgasm is associated with a particular type of respiratory pattern and intrauterine pressure change. The use of radiotelemetry devices to measure pressure and pH changes during coitus makes home studies possible. Further projects and areas for future study are considered.
The new discipline of sex therapy is making rapid strides because of the sound basis laid by pioneering work in the United States. It is, therefore, very much as a disciple that I present a review of some experiments in coital physiology from the Old World. Prior to the publications of Kinsey et al.' and Masters and Johnson2 only a few isolated experiments were found in the literature, and only in the past decade have writers or editors of textbooks of human physiology added to the brief pages on coitus in their volumes. The serious student of sexology has the benefit of knowing that his work may add to insight not only in the areas of sexual malfunction and its attendant psychological trauma, but also in matters of fertility and infertility, contraception, and world population. It becomes obvious that the intimate nature of the sexual act and the inhibitions of the researcher and society have been the major factors holding back progress in such vital issues. I propose to deal with some of the progress that has been made, to examine its relevance, and to suggest pointers for future research. Apologies must be offered to readers familiar with much of this work previously p ~ b l i s h e d ,but ~ it is earnestly hoped that some will benefit from lesser publicized data and from the Dr. Fox is associated with the Williamson laboratory part of the Academic Unit of Obstetrics, Gynaceology and Reproductive Physiology, and the Department of Obstetrics and Gynaecology, St. Bartholomew's Hospital Medical College University of London, England.
205
Downloaded by [University of Edinburgh] at 01:59 21 October 2014
206
Journal of Sex and Marital Therapy
reappraisal. Perhaps a few will be persuaded t o launch their own studies, having been fired with the spirit of inquiry as the author was when the message came in the reverse direction some 10 years ago. I t is necessary to understand our philosophy at the Williamson Labroatory for we feel that coital experiments should be conducted in the subjects’ home and away from the laboratory setting. Indeed, it would be difficult to do otherwise in Europe. To this end we have specifically designed some rather sophisticated electronic equipment so that participants are minimally inconvenienced, observers are not present, and the intimacy and naturalness of the sexual act is (as far as possible) preserved. Unless otherwise stated, the data is represented in the form of continuous recordings and represented by photographs of the original tracings and not artists3 impressions.
R E VIEW A N D DISCUSSION OF COITAL EXPERIMENTS
Blood Pressure Three experiments dealing with the rise in blood pressur during natural coitus have been published. Fox and Fox4 showed a rise in systolic blood pressure from a resting level of 125 mm Hg t o a peak of 175 mm Hg at ejaculation in a male subject (see Figure I ) and a rise from 100 to 200 mm Hg in a female subject at orgasm. In both sexes the blood pressure fell precipitately after the climax to a slightly lower level than the resting value and the total time for the peak elevation was about 90 seconds. Bevan, Honour, ar.d Stott’ made direct arterial recordings in one male and found an increase of 35 mm Hg systolic pressure and of 10 mm Hg diastolic pressure during coitus. The average pressure while lying in bed before the act was 85/60, during the act 120/70, and at the climax 160/100,with a postorgasmic fall to 60/30. All readings were taken through an arterial catheter, and the experiment was performed in the subject’s home because of the ingenious design of the equipment. Further studies using the same method were reported from Oxford by Littler, Honour, and Sleight6 with six male and one female participants in their respective homes. They were all normotensive, and rises in systolic pressure of up to 100 mm Hg systolic and 48 mm Hg diastolic were noted. Heart rate was increased to about 160/minute. Thcse findings are of more than academic interest since patients may present for advice about sexual activity after a coronary thrombosis or hypertensives may wish to know whether they are at risk. Death during coitus is not unknown, and Professor Lundberg, a Swedish neurologist, has stated that he has seen 25 cases of subarachnoid hemorrhage that occurred during coitus,’ the majority being cxtramarital liasons. In an attempt to study substances that might lower blood pressure during intercourse and at the climax, we investigated the effect of the beta-blocking agent pro-
Cyril A . Fox
Downloaded by [University of Edinburgh] at 01:59 21 October 2014
240 200
1
20 7
280
I
::I, I
I
I
240
I
0
I
I
,
,
::[ 0
Minutes FIGURE 1
1 I
,
,
,
,
Minutee
FIGURE 2
pranolol.8 It was found that in normotcnsive subjects an oral dose of 160 mg, taken 1% hours before the event, was able t o reduce the expected rise in systolic blood pressure without affecting the quality or ease of attainment of the climax (Figure 2). Thus far there are no reported studies in the literature concerning hypertensive patients, We are about to embark on one such study in London using a new noninvasive continuous blood pressure recorder of greater sophistication and accuracy than our previous digital recorder. Hellerstein and Friedman' have produced the best work with patients (postcoronary); they asked the patients to record their own EKGs on a special tape recorder in their own homes during sexual activity and to return the tapes t o them for analysis. Hcllerstein and Friedman were able t o give some reassurance to their pateints through this "sexercise tolerance test." Nevertheless, a quarter of the patients with angina complained of chest pain during coitus. A leading article in the British M e d i c h Journal" has summed up current thinking on sexual activity in angina patients. This is a neglected area o f sex counseling because patients may be too timid or otherwise preoccupied t o ask their specialists, and little information is available t o the latter even if they were interested. The results is that patients may be happily discharged from hospitals only t o find later that they have worries about a return t o a normal sex life.
Respiratory Pat t ems Respiratory changes during sexual activity were studies by Bartlctt," who noted an increase in pulmonary ventilation. He found a respiratory rate of 60/ minute and a minute volume of 50l/minute at the climax, all compatible with modcratcly severe exercise. Whcn we repeated these experiments," using a
208
Journal of Sex and Marital Therapy
Ejaculation
Downloaded by [University of Edinburgh] at 01:59 21 October 2014
I
2
1
0
’
minutes
FIGURE 3
Benedict-Roth Spirometer to obtain tracings, we were struck by the different preclimax patterns in the two sexes (see Figures 3 and 4.1, for there was marked apnoea in the female tracing. Both sexes showed the well-known postorgasmic hyperventilation (not seen so well in Figure 4 but shown clearly in our original publication). The important point about Figure 4 is that there are obvious periods of breath holding that may have considerable significance in the nature of the female orgasm, both subjectively and objectively (see the next section on intrauterine pressure changes). In a fascinating novel, The Great Railway Bazaar about a train journey across Asia, Paul Theroux writes, “Your eyes get accustomed to the dark and you see the waitress is naked. Without warning she jumps onto a chair, pokes a cigarette into her vagina and lights it, puffing it by contracting her uterine lungs.” I feel sure that she does this by attempting inspiration against a closed epiglottis while tensing the abdomnal and pelvic muscles. Sccond
Female Orgasm
First Female Orgasm
i FIGURE 4
Cyril A . Fox
209
Downloaded by [University of Edinburgh] at 01:59 21 October 2014
Intravaginal and Intra-uterine Pressure Changes In order to investigate the effects of coitus upon intravaginal and intrauterine pressures, it was necessary to design equipment that could be used in the absence of observers and in the bedroom. The radiotelemetry capsules shown in Figure 5 fulfilled the requirements since they were small (25 mmX9mm), unobtrusive, and reasonably well tolerated and had no attached wires. Basically, the capsule is powered by a tiny mercury battery (as in a deaf aid ) and emits a signal the lrequcncy of which can be modulated by changes in pressure and pH, respectively. A special receiver has been designed to pick up this signal and convert it to a linear tracing. The only requirement is that the participant does not move out of the confines of a loop aerial (1% m diameter) that is placed beneath the sheet on the bed. It is the only link between the capsule and its receiver. It must be stressed that the capsule has no attached wires. The setup is such that the participant, capsule, and loop aerial can be in one room and the receiver and recorder in another room. Since the original pressure device had a diameter of 9 mm, it was necessary to dilate the cervix to place it in the uteriis for measurements to be made, but we overcame this
C
A FIGURE 5
Journal of Sex and Marital Therapy
Downloaded by [University of Edinburgh] at 01:59 21 October 2014
210
problem by using an antenna (Figure 5B) of 3 mm diameter, and this worked just as well. During ejaculation the intravaginal pressure fell to a negative value of -20 cm water, probably due to the separation of the walls of the vagina by the straining penis. During female orgasm the intravaginal pressure rose to +20cm water, but the intrauterine pressure, after an initial rise to +40 cm, fell sharply to -10 cm water (Figure 6). In earlier experiements’* it had fallen as low as -26 cm. Thus there was a pressure gradient between the vagina and uterus that may have some importance in the consideration of sperm transport. It is possible that the female orgasm actively accelerates the passage of spermatozoa between vagina and uterus. Certainly, with the pressure lower in the uterus than in the vagina conditions art‘ more favorable for the necessary journey. Furthermore, the type of orgasm associated with these pressure changes was of the deeply satisfying type described by Fox and Fox4 and designated by SingerI3 as a “uterine” orgasm. This classification of female orgasm by Singer into (a) vulval, (b) uterine, and (c) blended (vulval + uterine) has much to commend it. It is based on the physiological fact that the vulval orgasm, previously termed clitoral orgasm, while pleasurable is not deeply satisfying and nonterminative, whereas the uterine orgasm is deeply satisfying and is terminative. There is some evidence from our work on intrauterine pressure changes that a nonterminative orgasm produces less quantitative change, and this is equally so with respiratory patterns. Close inspection of Figure 6 will show that there are two female orgasms. In the first, which was not terminative, the pressure rose steeply but did not drop below the base line to a negative F.O.
E
F. a
I -ve press -I0 -20
t FIGURE 6
Downloaded by [University of Edinburgh] at 01:59 21 October 2014
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pressure. The second orgasm was terminative and deeply satisfying; here we find a fall to a negative pressure within the uterus. The same effect with the two types of orgasm can be seen in our original publication (text figure 4a) using the unmodified pressure capsule.12 We believe that this is the true basis of the “uterine” orgasm and that the changes described occur only with this form of orgasm and with the particular breathing pattern described. It is illuminating t o find that what is so satisfactory subjectively is also capable of physiological insight and explanation. We dare not talk of the “best type of orgasm,” but it is gratifying to find that we have investigated one type that gives profound release and is propitious for conception. The female, of course, differs from the male in being able to experience repeated orgasms since there is no refractory period for the former. This lack of refractory period in the female does not necessarily mean that multiple orgasms are more pleasurable; they may indeed by a cause of concern because of the lack of release. It is probably that multiple orgasms are vulval, and if a woman complains of lack of satisfaction, conversion to uterine or blended orgasm may be achieved by counseling using the above physiological explanation or by suggesting deep penetration by the male.
pH Changes Within the Vagina Using a radiotelemetry pH capsule (Figure 5C), Fox, Meldrum, and WatsonI4 measured changes within the vagina and upon arrival of semen during coitus. The capsule was well tolerated, for it resembled a small pessary and was placed high in the vagina near the cervix where semen was likely to be ejaculated. The surprising finding was the rapid buffering of seminal fluid, for in the normally fertile male the pH of the seminal fluid was hardly affected. To put it another way, the vaginal pH (4)changed to pH7 (that of seminal fluid) within 8 seconds of ejaculation. It seems unlikely, therefore, that the vagina is a “hostile environment,’ in the normal situation. In the case of infertile or subfertile males we found that vaginal pH did not rise about pH5.5, and it is known that spermatozoa are immobilized by a pH o f less than 6. Poor buffering power and low ejaculate volume contribute to infertility. When a normally fertile male had lowered his ejaculatory volume and his sperm count by repeated ejaculation (four times in 48 hours was sufficient), he buffered as poorly as an infertile man. Again, it is interesting to speculate that what is, subjectively, increasingly less pleasurable (repeated ejaculation) is also physiologically significant in terms of procreation. Masters and Johnson’ have alluded to the fact that several days abstinence gives a more pleasurable ejaculation, and this fact may be brought out in general counseling. For the subfertile it is vital that “trying hard” should be discouraged.
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PROSPECTS FOR FUTURE RESEARCH. The need for further research into blood pressure changes has been stressed so that clinicians may be in a position t o advise patients with angina, coronary thrombosis, or hypertension. On a wider scale, thought should be given t o the disabled who wish t o lead a normal sex life and to the elderly who are beset with problems. Further research into breathing patterns in association with intrauterine pressure studies may reveal more about the female orgasm. As the telemetry capsules becomc smaller, and we are now testing ones with a 7 mm diameter, it may be possible to position these devices so that two or three are used in situ t o measure gradients of pressure. Similarly, with the reduction in size o f the pH capsule it should be possible t o measure intrauterine pH during orgasm. We feel that it should be possible t o measure the time taken for sperm t o enter the uterus if seminal fluid is “labeled” by placing a strong buffer solution in the vagina (say at pH 8) and there is a telemetry capsule in the uterus. When the labeled semen at pH8 reaches the intrauterine device, this should register above the usual uterine pH of about 7.2. We await the technology for this experiment and are assured that it is almost available. We have previously reviewed hormonal changes during ~ o i t u s and , ~ further consideration appears elsewhere in this issue. The problem of sampling during coitus has been the major factor in limiting such studies. Some form of automatic sampler has been suggested, but for the present we must rely on medical. or paramedical participants who are prepared t o use an indwelling “butterfly” canulla. This can be kept in a vein for up to 24 hours without discomfort. It remains patent with the use of heparin-saline, and frequent sampling can be carried out even by the wearer of the canulla. With so many hormonal assays now available by radioimmunoassay, there is great scope for the sex physiologist.
REFERENCES 1. Kinsey AC, Pomeroy WB, Marin CE, Cebhard PH: Sexual Behavior in the Human Female. Philadelphia, Saunders, 1953. 2. Masters WH, Johnson VE: Human Sexual Response. Boston, Little, Brown, 1966. 3. Fox CA: Recent studies in human coital physiology. Clin Endoctinol Metabof 2:527-541, 1973. 4. Fox CA, Fox B: Blood pressure and respiratory patterns during human coitus. Reprod Fertil 19:405-415, 1969. 5. Bevan AT, Honour AJ, Stott FH: Direct arterial pressure recording in unrestricted man. Clin Sci 36:329-344, 1969. 6 . Littler WA, Honour AJ, Sleight P: Direct arterial pressure, heart rate and electrocardiogram during human coitusj. Reprod. FertiZ40:321-331, 1974. 7 . Lundberg P. Personal communication, 1974. a. Fox CA: Reduction in the rise of systolic blood pressure during human coitus by the betablocking agent propranolol. J Reprod Fertil 22:587-590, 1970. 9. Hellerstein HK, Friedman EH; Sexual activity and the post-coronary patient. Arch Intern Med 125:987-999, 1970.
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10. Coitus and coronaries. 3rMed J 1:414, 1976. 1 1 . Bartlett RJ; Physiologic responses during coitus. J Appl Physiol9:469472, 1956. 12. Fox CA, Wolff HS, Baker JA: Measurement of intra-vaginal and intra-uterine pressures during human coitus by radio-telemetry. J Reprod Fertil 22243-251, 1970. 13. Singer I: The Goals of Human Sexuality. New York,Norton, 1973, Chapter 3. 14. Fox CA, Meldrum SJ, Watson BW: Continuous measurement by vaginal pH during human coitus. J Reprod Fertil 33:69-75, 1973.
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