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Thermal Physiology and Thermoregulation
Published in James Stewart Campbell, M. Nathaniel Mead, Human Medical Thermography, 2023
James Stewart Campbell, M. Nathaniel Mead
Different phases of the menstrual cycle are linked with fluctuations in body temperature. Body temperature may be approximately 0.4°C (0.7°F) higher in the luteal phase (after ovulation) than in the earlier follicular phase of the cycle.115 When exercising in the mid-luteal phase, women with normal menstruation show less effective heat dissipation in comparison with thermoregulation during the mid-follicular phase. Gross measurements of skin heat dissipation were found to be lower in the mid-luteal phase under thermoneutral conditions; moreover, the set point of core temperature also seems to be elevated during that phase.116 According to an early study, warm breasts compared to a cool sternal area occur in the pre-ovulatory period, while the situation was reversed during the luteal phase. These cyclic changes did not occur in post-menopause subjects or women taking oral contraceptives.117
Decreased submaximal oxygen uptake during short duration oral contraceptive use: a randomized cross-over trial in premenopausal women
Published in Thomas Reilly, Julie Greeves, Advances in Sport, Leisure and Ergonomics, 2003
In normally menstruating women, maximal aerobic capacities have been shown to be slightly lower during the luteal phase compared to the follicular phase (Lebrun et al. 1995). The majority of the studies to date failed to demonstrate any changes in submaximal V̇O2 along the menstrual cycle (Jurkowski et al. 1981, Eston and Burke 1984, Dombovy et al. 1987, De Souza et al. 1990). In some studies, high ovarian steroid status observed during the luteal phase has been shown to be associated with higher resting and submaximal V̇O2 values than those observed at low endogenous hormone concentrations during the early or mid-follicular phase (Hessemer and Bruck 1985, Williams and Krahenbuhl 1997). The concentrations of synthetic steroids were higher during the 21 days on OC use than during the off OC week. Therefore, the present study suggested specific cardiorespiratory responses to changes in synthetic steroid levels.
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Published in Asim Kurjak, Ultrasound and Infertility, 2020
Joseph G. Schenker, Aby Lewin, Menashe Ben-David
Further follicular development takes place in the leading follicle when LH receptors on the granulosa cell membranes are being synthesized. Presence of both FSH and estradiol is essential for the synthesis of LH receptors in the granulosa cells. Such conditions exist only in the leading follicle, which has the capacity to bind even the declined peripheral FSH concentration (due to high receptor levels) and thus to induce a microenvironment rich with estradiol. Increasing amount of peripheral estradiol can act directly on the pituitary gonadotropes to trigger positive feedback on LH. Concentrations higher than 200 pg /ml of estradiol are needed to achieve the positive feedback on pituitary LH. Moreover, estrogen feedback on LH secretion enhances not only the quantity of LH release, but also its quality by modulation of the LH molecule to one with a higher biological activity. During the late follicular phase, estrogens rise rapidly, reaching a maximum 24 to 36 h before the ovulation. Concomitantly, there is a decline in the circulating FSH to this nadir while FSH increases steadily and then rapidly in a surge-like burst at midcycle, accompanied by a lesser surge of FSH. In the presence of high estradiol concentration and adequate amount of FSH, activation of the granulosa cell LH receptors by the abundant LH will lead to a process of luteinization and an increase in progesterone production. If, however, there is no adequate amounts of either estradiol or FSH in the microenvironment of the follicles, the follicles react to LH bolus with atresia rather than luteinization.
Menstrual cycle alters training strain, monotony, and technical training length in young
Published in Journal of Sports Sciences, 2019
Gislaine Cristina-Souza, Ana C. Santos-Mariano, Carla C. Souza-Rodrigues, Raul Osiecki, Sandro F. Silva, Adriano E. Lima-Silva, Fernando R. De Oliveira
The Menstrual Cycle (MC) is determined by a synchronic response involving the hypothalamic-pituitary-ovarian axis (Reilly, 2000). A regular MC takes between 26 and 35 days and can be divided into three phases: 1) follicular; 2) ovulatory, and 3) luteal (Constantini, Dubnov, & Lebrun, 2005). The follicular phase (FP) is characterized by high levels of follicle-stimulating hormone (FSH) and low levels of luteinizing hormone (LH), estradiol and progesterone (Constantini et al., 2005; Oosthuyse & Bosch, 2010). The ovulatory phase (OP) is characterized by low levels of FSH and progesterone, and high levels of LH and estradiol (Constantini et al., 2005; Oosthuyse & Bosch, 2010). Finally, the luteal phase (LP) is characterized by low levels of LH and FSH, and high levels of estradiol and progesterone (Constantini et al., 2005; Oosthuyse & Bosch, 2010).