Hormonal Contraception, Body Water Balance and Thermoregulation
Abstract
To test the hypothesis that estrogen enhances water and sodium retention, we compared the fluid regulatory responses to 150 min of exercise-induced dehydration, followed by 180 min of ad libitum drinking during the follicular and luteal phases of the menstrual cycle, and following treatment with an estrogen/progestin oral contraceptive (oCP) and a progestin-only oCP, in a double-blind, randomized, cross-over design. The women (n=9, 25 + 1 yr, 62.5 + 3.6kg,) had a mean blood volume of 67.3 + 2.l ml/kg, and a VO2 peak of 30.6+ 2.4 ml- min on the recumbent bicycle ergometer Due to the double- blind design, the pills have been identified only as OCP-A or B at this point. Preliminary data on 6 women who have completed testing with oCP-A and S women with oCP-B reveal a downward sh,,ft in osmotic regulation of plasma arginine vasopressin during the luteal phase and both oCP's compared to the follicular phase, which was present during rest and exercise. However, this shift was not accompanied by plasma volume expansion. Fluid and electrolyte loss during exercise were unaffected by phase of the menstrual cycle or oCP treatment. Fluid and electrolyte retention was greatest during ad libitum drinking the follicular phase, however, overall fluid balance was similar across all trials.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1997
- Accession Number
- ADB233865
Entities
People
- Ethan R. Nadel