Fluctuation of Water Intake and of Hydration Indices during the Day in a Sample of Healthy Greek Adults

Abstract

Mild dehydration may occur during specific periods of the day because of poor hydration habits and/or limited access to a variety of beverages or foods, for example, in work environments. Measurement of hydration indices in spot or in 24 h urine samples may mask mild dehydration in specific periods of the day. Healthy subjects (n = 164; 74 females; age 38 ± 12 years) living in Athens, Greece were enrolled in the study. Subjects recorded their solid food and drink intakes and recorded and collected all urinations for three consecutive days. Water intake was analyzed in 24 h and 6 h periods from wake-up time and scored for variety. Urine hydration indices (osmolality, volume, color, specific gravity) were analyzed in 24 h samples, in morning urine samples and in samples collected in 6 h periods from wake-up time. Fluctuations during the day were significant for the intake of drinking water, hot beverages, milk, fruit and vegetable juices, and alcoholic drinks and for urine osmolality, volume, color, and specific gravity. The urine volume of the first 6 h period after wake-up time (557 ± 231 mL/day) reflects by 76% the 24 h urine collection (1331 ± 144 mL/day). Water intake from all beverages, with the exception of alcoholic beverages, was greater in the first 6h period (morning period) and decreased throughout the day. Hydration indices changed accordingly. The 6 h timed urine sample collected reflects indices in samples collected over 24 h better than any spot urine sample.

The Timing of Water and Beverage Consumption During the Day Among Children and Adults in the United States: Analyses of NHANES 2011–2016 Data

“…There is very little science on population water consumption patterns during the day. One recent study, conducted in Greece, explored the fluctuation in water intakes and hydration indices during the day, looking for signs of transient dehydration in a sample of healthy adults [16]. While water intakes did go up and down during the day, as they did here, the term fluctuation generally refers to an unpredictable and irregular rising and falling.…”

“…One recent suggestion was that mild dehydration may occur in a transient manner when water and fluids are not consumed, either because of poor access to water or beverages or because of poor drinking and eating habits [16]. The present study explored daily fluctuations in water intakes from water, beverages, and foods in a large and nationally representative sample of children and adults in the US.…”

Daily water regime and sample sampling affect Blood and Urine parameter value change in healthy individuals

“…The study reveals the association of total uid intake with Urine colour, osmolarity, speci c gravity and solute concentration [13] . The crosssectional analysis showed the association of Urine volume with osmolarity, gravity and osmolarity, osmolarity and colour, colour and gravity [12,14] . There are no publications regarding the in uence of 5 days water intake combined with 2 days of arbitrary consumption of large water amount till 1 st sampling and lower water amount till 2 nd sampling in T group and continuous water intake in C group during 1 st and 2 nd sampling on Blood and Urine parameters in healthy individuals, as this is the case with this study.…”

“…The relationship between hydration, Urine/Blood biomarker and total uid intake in pregnant and lactating women during 3 semesters is estimated [11] . Observational studies recorded and assessed the amount of rm food/ beverage and Urine parameters (osmolarity, volume, gravity and colour) in healthy children and elderly individuals for 24h [12,13] . A cross-sectional study on healthy Male college students in China assed hydration status, uid intake and Urine biomarker (osmolarity, speci c gravity, pH, the concentration of K + , Na + and Cl 2-) for 24 hours [14] .…”

Daily water regime and sample sampling affect blood and urine parameter value change in healthy individuals

“…The relationship between hydration, urine/blood biomarker, and total fluid intake in pregnant and lactating women during three semesters is estimated (McKenzie et al, 2017). Observational studies recorded and assessed the amount of firm food/beverage and urine parameters (osmolarity, volume, gravity, and color) in healthy children and elderly individuals for 24 h (Athanasatou, Kandyliari, Malisova, & Kapsokefalou, 2019;Kavouras et al, 2017). A cross-sectional study on healthy male college students in China assed hydration status, fluid intake, and urine biomarker (osmolarity, specific gravity, pH, the concentration of K + , Na + , and Cl 2− ) for 24 h (Zhang et al, 2017).…”