Water Intake and Hydration Indices in Healthy European Adults: The European Hydration Research Study (EHRS)

Abstract

Hydration status is linked with health, wellness, and performance. We evaluated hydration status, water intake, and urine output for seven consecutive days in healthy adults. Volunteers living in Spain, Germany, or Greece (n = 573, 39 ± 12 years (51.1% males), 25.0 ± 4.6 kg/m2 BMI) participated in an eight-day study protocol. Total water intake was estimated from seven-day food and drink diaries. Hydration status was measured in urine samples collected over 24 h for seven days and in blood samples collected in fasting state on the mornings of days 1 and 8. Total daily water intake was 2.75 ± 1.01 L, water from beverages 2.10 ± 0.91 L, water from foods 0.66 ± 0.29 L. Urine parameters were: 24 h volume 1.65 ± 0.70 L, 24 h osmolality 631 ± 221 mOsmol/kg Η2Ο, 24 h specific gravity 1.017 ± 0.005, 24 h excretion of sodium 166.9 ± 54.7 mEq, 24 h excretion of potassium 72.4 ± 24.6 mEq, color chart 4.2 ± 1.4. Predictors for urine osmolality were age, country, gender, and BMI. Blood indices were: haemoglobin concentration 14.7 ± 1.7 g/dL, hematocrit 43% ± 4% and serum osmolality 294 ± 9 mOsmol/kg Η2Ο. Daily water intake was higher in summer (2.8 ± 1.02 L) than in winter (2.6 ± 0.98 L) (p = 0.019). Water intake was associated negatively with urine specific gravity, urine color, and urine sodium and potassium concentrations (p < 0.01). Applying urine osmolality cut-offs, approximately 60% of participants were euhydrated and 20% hyperhydrated or dehydrated. Most participants were euhydrated, but a substantial number of people (40%) deviated from a normal hydration level.

Characteristics of Beverage Consumption Habits among a Large Sample of French Adults: Associations with Total Water and Energy Intakes

“…Although we found statistically significant differences in TWI according to the seasonality, the difference of 120 g/day for men and 80 g/day for women between water intakes during winter and summer was limited compared to results of previous studies in other European countries [37,38]. However, this result can be explained by the temperate climate in France, with few extreme temperatures.…”

“…In a Mediterranean country such as Greece [37], a 40% increase in total water intakes was found between winter and summer. In another study with subjects from Germany, Spain and Greece [38], the difference was 200 g/day between winter and summer.…”

Development and relative validity of a self‐administered semi‐quantitative drinks frequency questionnaire, validated in a population of university students

“…16,22,40,41 Because of the importance of accurately recording drinks consumption, several fluid-specific questionnaires have been validated in other languages. 13,42 In Greece, a similar tool was developed some years ago, 43 evaluating water intake from liquid, solid foods and water, as well as urine, faeces and sweat water loss. However, because of its different aim, it is not a quick assessment tool, as the DFQ.…”

Fatigue and fluid hydration status in multiple sclerosis: A hypothesis

“…Hydration status was classified by a USG threshold of 1.015, which is optimal to distinguish subjects with high-hydration (HiH) and LoH status. 10,11,14 …”