The effects of 6 months of increased water intake on blood sodium, glomerular filtration rate, blood pressure, and quality of life in elderly (aged 55-75) men

J Am Geriatr Soc. 2006 Mar;54(3):438-43. doi: 10.1111/j.1532-5415.2005.00606.x.


Objectives: To study whether there are any negative or positive effects of 6 months of increased fluid intake in reasonably healthy elderly men.

Design: Randomized trial.

Setting: Community-based.

Participants: One hundred forty-one healthy participants aged 55 to 75.

Intervention: One group was given the advice to increase their daily fluid intake by 1.5 L of water; the other group was given placebo medication (8 mL inactive syrup per day).

Measurements: At 6 months blood sodium, glomerular filtration rate (GFR), blood pressure, and quality of life (QOL) were measured. The changes in water turnover were measured using deuterium.

Results: Most subjects did not manage to increase their fluid intake by 1.5 L. The average increase in the intervention group was approximately 1 L. Twenty-four-hour water turnover in the water group was 359 mL (95% confidence interval=171-548) higher than that of the control group at 6-month follow-up. Blood pressure, sodium level, GFR, and QOL did not change significantly in either group during the intervention period. In addition, the cases reporting a worsening on the effect measures were equally distributed over the two study groups.

Conclusion: The advice to increase fluid intake by 1.5 L had no negative effects in reasonably healthy men aged 55 to 75.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aging / physiology*
  • Blood Pressure / physiology*
  • Body Water / metabolism*
  • Drinking / physiology*
  • Follow-Up Studies
  • Glomerular Filtration Rate / physiology*
  • Humans
  • Male
  • Middle Aged
  • Quality of Life*
  • Reference Values
  • Sodium / blood*
  • Time Factors


  • Sodium