Water Turnover, Urinary Markers Of Hydration, And Mood In Men And Women

Abstract

PURPOSE: Past research has identified relationships between daily total water intake (TWI) measured by diet diary with dimensions of mood in free living, and laboratory confined men and women. However, diet records have been associated with subjective errors and thus these findings should be confirmed in objective of body water turnover (WTO). METHODS: 49 women (42±14y, 164±6cm, 71±16kg) and 46 men (40±14y, 177±7cm, 81±16kg) volunteered for WTO measurement via deuterium oxide dilution technique over two consecutive weeks. Total water intake (TWI) was calculated as WTO (L·d-1) - metabolic water production. The Profile of Mood State questionnaire (POMS) was administered in the morning on the 4th day of each week. Physical activity was assessed with the International Physical Activity Questionnaire. The influence of the prior days, and acute hydration status (via urine osmolality) on mood was considered with; a) 24h urine collections comprised of the full day leading up to, and, b) single urine samples collected immediately prior to completion of the POMS. Measurements were averaged between weeks. Multivariate linear regression was completed to assess if WTO or either of the hydration markers predicted any of the 6 POMS sub-scales or the composite mood measurement of total mood disturbance, over and above the influence of age, body mass index, and MET minutes of physical activity completed during the week. RESULTS: The vigor sub-scale of was significantly associated with WTO, (Fchange[1,94]=5.00, R2change=0.05, Beta=0.23, P=0.03). This finding was not apparent in relationships with 24h urine osmolality (Fchange[1,94]=2.58, R2change=0.03, Beta=0.16, P=0.11) or single sample urine osmolality (Fchange[1,94]=2.65, R2change=0.03, Beta=-0.17, P=0.10). No other sub-scales or TMD were significantly related to WTO, or hydration indices, after accounting for the covariates. CONCLUSIONS: This study confirms a positive relationship between mood and fluid intake using direct measurement of WTO. The lack of significance to urinary hydration markers is indicative of the multi-faceted composition of urine concentration (i.e., kcal, protein intake, etc.). However, daily WTO is modestly associated with mood and should be further explored in controlled laboratory conditions to further elucidate this relationship.