Related Experiment Video
Updated: Aug 8, 2026

Collecting Sleep, Circadian, Fatigue, and Performance Data in Complex Operational Environments
Published on: August 8, 2019
Influences of diurnal bright or dim light exposure on urine volume in humans
Ki-Ja Hyun1, Shinya Nishimura, Hiromi Tokura
1Department of Environmental Health, Nara Women's University.
Abstract:
We investigated with eight healthy females if 8 hr diurnal (0700 to 1500 h) bright rather than dim light (5,000 vs. 80 lx) influenced urine volume. Environmental illuminance was made identical at all other times besides 07:00 to 15:00 h. The participants spent time at strictly regulated schedules in a bioclimatic chamber (26 degrees C, relative humidity 60%) for 57 h. Blood was drawn (2 ml) just before lunch in order to calculate Creatinine clearance (Ccr). Urine volume was significantly higher during wakefulness and the 8-h sleep period with bright rather than dim light. Ccr was significantly higher after bright light. The results were discussed in terms of suppression of the sympathetic nerve system under the influence of diurnal bright light exposure. We also discussed these in terms of physiological polymorphisms.
More Related Videos
Related Concept Videos
Chronopharmacokinetics: Circadian Rhythms and Influence on Drug Response
The time of drug administration is an important factor to consider, as it can influence the toxic dose of a drug. For example, a study conducted by Prins et al. in 1997 examined the effects of the timing of...
Urine Studies I: Urinalysis
One-Compartment Open Model: Urinary Excretion Data and Determination of k
Drug Dosing in Renal Diseases: Dose Adjustments Based on Drug Clearance and Elimination Rate Constant
Drug Dosing in Renal Diseases: Measurement of Serum Creatinine Concentration and Clearance
Formation of Dilute Urine
Filtrate Osmolarity in the PCT
Initially, as the filtrate passes through the proximal convoluted tubule (PCT), its...
