Few oligo-amenorrheic athletes have vasomotor symptoms
Introduction
The majority of women in Western countries report vasomotor symptoms with hot flushes and sweating around menopause [1], [2]. Vasomotor symptoms are the most typical symptoms around menopause [1]. During the flushes it is possible to objectively register increased pulse rate, skin-temperature, skin-moisture, peripheral vasodilatation and decreased central temperature using plethysmography, thermogram or registration of skin-conductance [3]. There is a temporal correlation between elevations of serum luteinizing hormone (LH) and the flushes [4], [5]. The flushes are probably elicited by a sudden resetting in the thermoregulatory center, whereas the rapid elevations of LH are caused by an increase in gonadotrophin releasing hormone (GnRH) pulse rate or amplitude [4], [5].
β-Endorphins are regulatory peptides secreted by neurones in the hypothalamus, and are in turn regulated by sex steroids. β-Endorphins inhibit the release of GnRH and, if β-endorphin concentrations are lower after menopause, the secretion of GnRH, and thereby also LH, is allowed to increase [6], [7]. A decrease in β-endorphin levels after menopause probably also affects the thermoregulatory centre, located in the hypothalamus, and makes it less stable. This postulated mechanism concerning menopausal vasomotor symptoms is speculative, but β-endorphins are known to influence the thermoregulation in animal models [8], [9] as well as in humans [10].
Already in 1962 Erdelyi reported on menstrual disorders in female athletes [11]. Since then an increasing number of reports have shown that menstrual disorders including amenorrhea are common in women taking part in strenuous exercise [12], [13], [14], [15]. Decreased bone density and fracture risk are signs of the hypoestrogenism, which is the cause of the amenorrhea in these subjects [15].
Vasomotor symptoms, typical and characteristic symptoms in hypoestrogenic postmenopausal women, have not been reported in amenorrheic athletic women, although they are known to have low estrogen levels. The reason could be that they do not experience such symptoms, but also that these symptoms have not been of interest to researchers. If vasomotor symptoms do not exist among amenorrheic athletes this could be a clue to the aetiology of both the menstrual disturbance in athletes and the vasomotor symptoms around menopause.
The aim of the present study was to assess if oligo- and amenorrheic athletes have vasomotor symptoms and in such case to compare the prevalence of flushes with that found in women around menopause.
Section snippets
Material and methods
A total of 252 female athletes of fertile age were recruited to the study. They were either asked to take part when they were nominated to the Swedish national team in long-distance running (n=7) or their names and addresses obtained from national sports organisations of long-distance running and orienteering (n=116). Furthermore the 100 women with the best results from ‘Vasaloppet’ 1996 (a 90 km cross country skiing race arranged yearly with over 10 000 participants) were invited. Finally 29
Athletes
The response rate among the athletes was 79.0% (n=199). Not all questionnaires were completely filled in, but 196 questionnaires could be analysed concerning vasomotor symptoms in relation to menstrual status. Thirty-five percent of the athletes were current users of oral contraceptives, and all of them reported regular cycles. Of the 129 women who did not use oral contraceptives, 36% (47/129) had >40 days intermenstrual intervals and 16% (20/129) had amenorrhea since at least 3 months at the
Discussion
This study showed that very few oligo-amenorrheic athletes had vasomotor symptoms and the prevalence was similar, even in the amenorrheic group, to that found in athletes with regular cycles. This is contrary to present and previous findings concerning women who are amenorrheic after menopause, when the prevalence of vasomotor symptoms is at least 50% during the first years [1], [2]. Although the athletes had a significantly lower prevalence and frequency of vasomotor symptoms than the
Acknowledgements
We would like to thank Angelica Lindén, MD, PhD for valuable discussion concerning the design and interpretation of this study. Source of funding: We are indebted to the Swedish Medical Research Council, grant no K98-17X-12651-01A, The Swedish Foundation for Health Care Sciences and Allergy Research and Cancer och Trafikskadades Förbund for financial support to this study.
References (37)
- et al.
The normal menopause transition
Maturitas
(1992) - et al.
Climacteric symptoms among women aged 60–62 in Linköping, Sweden, in 1986
Maturitas
(1988) - et al.
The physiology and measurements of hot flushes
Am. J. Obstet. Gynecol.
(1987) - et al.
Endogenous opiates: 1990
Peptides
(1991) - et al.
Effect of mu-, kappa-, and delta-selective opioid agonists on thermoregulation in the rat
Pharmacol. Biochem. Behav.
(1992) - et al.
Effect of steroids on body temperature in postmenopausal women. Role of endogenous opioids
Life Sci.
(1992) - et al.
Effects of triptorelin versus placebo on the symptoms of endometriosis
Fertil. Steril.
(1998) - et al.
Response of plasma endorphins, corticotropin, cortisol, and luteinizing hormone in the corticotropin-releasing hormone stimulation test in eumenorrheic and amenorrheic athletes
Fertil. Steril.
(1991) - et al.
The effect of acute exercise on pulsatile release of luteinizing hormone in women runners
Am. J. Obstet. Gynecol.
(1985) - et al.
The hot flush