Date of Graduation


Document Type


Degree Name

Master of Science in Kinesiology (MS)

Degree Level



Health, Human Performance and Recreation


Stavros A. Kavouras

Committee Member

Michelle Gray

Second Committee Member

Matthew Ganio


Health and environmental sciences


Body weight and hydration markers change greatly during strenuous exercise, especially in the heat. However, in a non-athletic population, changes in body weight and hydration markers may not be so obvious. It is important to classify the normal fluctuation of these measurements for future studies in order to delineate when an intervention results in a change outside of what can be expected during normal daily living. PURPOSE: The purpose of this study was to describe the normal fluctuations in body weight and urine hydration markers over the course of 29 days. METHODS: One-hundred two male and female participants, ranging from 18 to 65 years were measured on 12 separate morning visits over the course of 29 days. All the subjects were apparently healthy and none of them exercised more than four hours per week. During each visit, subjects were weighed and provided a urine sample for analysis of osmolality (UOsmo) and specific gravity (USG) measurement. The results from these measurements were analyzed using a one-way, repeated measures, analysis of variance test to evaluate main effects of time on body weight, UOsmo, and USG. The coefficient of variance was also used to compare week to week values. RESULTS: Urine osmolality and USG showed no statistical significance across time. Mean average for urine osomolality was 582.27 278.23 with p = 0.056 and USG means were 1.015 0.008 with p = 0.239. Body weight did show change across time with a mean average of 76.25 16.91 with p = 0.005. CONCLUSION: Urine osmolality and USG biomarkers indicate stability over a period of 29 days, while body weight seems to be a more inconsistent factor.