Effects of Time of Day, Age and Gender on the Ability to Conserve Water Load
Abstract
Seven adults, 2 women in the follicular phase or the menstrual cycle and 5 men, were studied. We intend to provide information relating to age, gender, and the phase of the menstrual cycle when the study is complete. The question addressed to date, regards the mechanism explaining the diurnal urinary response to a water load of 12 ml/kg lean body mass. We observed a 20% greater (P < 0.05) diuresis in response to a water load during the daytime compared to nighftime, despite a slightly lower resting plasma osmolality (Posm) during the nighttime. The plasma osmolality resulting after the drink was similar during the daytime and nighttime. Despite this, plasma vasopressin levels were lower after the drink during the daytime compared to the nighttime (P <0.05), and the levels were reduced relative to predrink controls for a longer time during the daytime (P <0.05). Free water loss accounted for most of the diuretic response as expected, and the increased cumulative urine flow appears to result from a prolonged decrease in urine osmolality and increase in free water clearance during the daytime compared to the nighttime.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1995
- Accession Number
- ADB227588
Entities
People
- John R. Claybaugh