Influence of menstrual cycle on shivering, skin blood flow, and sweating responses measured at night

Abstract

In 10 women, external cold and heat exposures were performed both in the middle of luteal phase (L) and in the early follicular phase (F) of the menstrual cycle. Serum progesterone concentrations in L and F averaged 46.0 and 0.9 nmol X l-1, respectively. The experiments took place between 3:00 and 4:30 A.M., when the L-F core temperature difference is maximal. At neutral ambient temperature, esophageal (Tes), tympanic (Tty), rectal (Tre), and mean skin (Tsk) temperatures averaged 0.59 degrees C higher in L than in F. The thresholds for shivering, chest sweating, and cutaneous vasodilation (heat clearance technique) at the thumb and forearm were increased in L by an average of 0.47 degrees C, related to mean body temperature [Tb(es) = 0.87Tes + 0.13 Tsk] and to Tes, Tty, Tre, or Tsk. The above-threshold chest sweat rate and cutaneous heat clearances at the thumb and forearm were also enhanced in L, when related to Tb(es) or time. The metabolic rate, arm blood flow, and heart rate at thermoneutral conditions were increased in L by 5.0%, 1.1 ml X 100 ml-1 X min-1, and 4.6 beats X min-1, respectively. The concomitant increase in threshold temperatures for all autonomic thermoregulatory responses in L supports the concept of a resetting of the set point underlying the basal body temperature elevation in L. The effects of the increased threshold temperatures are counteracted by enhanced heat loss responses.

Effects of menstrual cycle and physical training on heat loss responses during dynamic exercise at moderate intensity in a temperate environment

“…This disagreement between earlier studies and the present study may have resulted, in part, from differences in the experimental conditions, including differences in exercise position [Fukuoka et al (14) and Grucza et al (15) exercised their subjects in an upright position], indexes of core body temperature (the earlier studies used rectal temperature), or in the physical characteristics of the subjects. Previous studies have suggested that T es is a better index with which to evaluate heat loss responses than rectal temperature (17,18,28,36). Therefore, our results may be more accurate than those of earlier studies in which rectal temperature was used to evaluate sensitivity of the core temperature (14,15).…”

“…thermoregulation; estradiol; progesterone; long-term endurance training; heat acclimatization HEAT LOSS RESPONSES, SUCH as sweating and cutaneous vasodilation, during exercise in women differ from those in men because female hormones modify the responses after puberty (3). All studies of the effects of the menstrual cycle on heat loss responses during exercise have demonstrated that the core body temperature thresholds for sweating and cutaneous vasodilation are higher during the luteal phase of the menstrual cycle than during the follicular phase (14,15,17,18,23,31,33,35). In addition, the rise in the core body temperature threshold for sweating and cutaneous vasodilation during the luteal phase is mainly due to elevated progesterone concentrations (8, 31).…”

Menstrual cycle and oral contraceptive use do not modify postexercise heat loss responses

“…Baseline resting esophageal temperature was ϳ0.18°C higher in the LP compared with the FP. Although estrogen and progesterone are known to have varying effects on core body temperature response (53,54), the transient increase in esophageal temperature observed during the LP appears to be related to combined influence of the higher levels of circulating sex hormones, progesterone and estrogen (20,21).…”

Do Glucose Containing Beverages Play A Role In Thermoregulation, Thermal Sensation, And Mood State?

“…The sample consisted of males, as exercise intensity and duration could be confounded with a co-ed sample (i.e., males vs. females may require a different level of exercise to produce the level of dehydration desired) [13][14][15]. Further, only Caucasian males were utilized, as non-whites and female have demonstrated differences in thermoregulation [16,17]. The study protocol was approved by the Institutional Review Board at Kent State University.…”