[The Bahía 2008 Study: hydration barometer in the Spanish population]

Vital functions require a balance between the loss and ingestion of liquids. There are no studies about hydration on Spanish population.

6,508 questionnaires were applied to a randomly selected Spanish population, together with a 24-hour recall in order to measure liquid consumption and variables related to it.

The average consumption of liquids was 2,089.5 +/- 771.4 and 6.05 drinking times/day. 3,423 persons (52.6% of the studied people, CI 95% 51.3%-53.8%) were well-hydrated when considering their individual intake. The frequency and volume of drinking decreased with age. 61% (CI 95% 58.64%-64.01%) of the population older than 65 years were badly hydrated. The greatest bottled water consumption corresponded to the youngest population (18-29 years). The greater the physical activity, the greater the beverages consumption (1,987.6 +/- 705.5 ml vs 2,345.8 +/- 928.1 ml, low vs. intense physical activity, respectively). With regard to the intake frequency and volume, mineral and tap water were the most consumed. Those who drank mineral water exceeded the 2 l-recommendation in order to maintain a good hydration status. 59.8% (CI 95% 57.83%-61.76%) of those who preferred mineral water drank more than 2 l/day and drank more times/day and in greater amounts. There was a greater frequency and amount of beverage consumption when people lived in the same house, and particularly more in houses where children were living (2,197.4 +/- 767.8 ml vs 2,055.7 +/- 769.86 ml and 6.4 +/- 2.2 times vs 5.9 +/- 1,9 times, in homes with or without children, respectively). Bottled water was preferred at home (79.07%) and at work (15.61%).

Only half of the Spanish population is well hydrated. Sixty-one percent of people over the age of 65 years were poorly hydrated, consequence it is imperative to promote its consumption.