Water is essential for life as it is the main constituent of cells, tissues, and organs¹. Water comprises from 75% of body weight in infants to 55% in the elderly². Water is a vital nutrient and essential for basic functions in the human body. It transports nutrients to cells and removes waste, serves as the medium in which all transport systems function, and maintains vascular volume which allows blood circulation¹⁻². Thus, the cardiovascular and respiratory system, the digestive tract, the reproductive system, the kidney, liver, and the brain, all depend on adequate hydration to function properly¹⁻². Water also keeps our joints lubricated, prevents infections, and improves our sleep quality, cognition, and mood². Water regulates the body’s temperature and can influence cognition³⁻⁵. Even mild dehydration can alter concentration, alertness and short-term memory⁶⁻⁷. Water is also important for preventing constipation and headaches2,8-9. Some observational studies indicate that dehydration, in addition to impairing concentration and increasing irritability, can serve as a trigger for migraines⁸⁻⁹.
So, how much water do we need a day? Adequate water intake for sedentary adults is between 2-2.5 L per day⁷. At SSIHI, we recommend half your body weight in ounces daily (80 lb = 40 oz water). For most, food contributes 20–30% of daily water intake, whereas drinks contribute 70–80% of total water¹⁻². It is ideal to drink filtered water and avoid sweetened drinks, including soda and fruit juice, and consume water-rich foods. Four foods with the highest water content include: watermelon, cucumber, lettuce, and celery. Of note, over a 24 hour period, the average adults loses 1-2 L of urine, 450 mL of water evaporated via skin and 250-350 mL via the respiratory tract, and finally 200 mL of water through feces⁷. Clinical symptoms of dehydration are nonspecific, but may present as dry mucus membranes in the mouth and nose, chapped lips, and changes in urine color1-2,7. The color of your urine maybe a reasonable gauge of hydration status. Darker urine may indicate under dehydration while lighter urine may indicate adequate hydration⁷. Most importantly, staying hydrated is one of the best and simplest dietary and lifestyle approaches to prevent acute and/or chronic disease.
Tips to keep you hydrated:
- Start each morning with a large glass of water.
- Keep a reusable water bottle on hand and easily accessible. Pick a bottle you like and will want to use.
- Set goals to finish entire water bottle before lunch and again before dinner.
- Set an alarm on your phone or watch to remind you to drink.
- Infuse fruit and herbs to make water more palatable.
- Make unsweetened iced tea by infusing multiple tea bags and keeping in the fridge.
References:
- Jéquier E, Constant F. Water as an essential nutriment: the physiological basis of hydration. Eur J Clin Nutr. 2011;65(7):877-877. doi:10.1038/ejcn.2011.41
- Popkin B, D’Anci K, Rosenberg I. Water, hydration, and health. Nutr Rev. 2010;68(8):439-458. doi:10.1111/j.1753-4887.2010.00304.x
- Sawka M. Hydration Effects on Temperature Regulation. Int J Sports Med. 1998;19(S 2):S108-S110. doi:10.1055/s-2007-971971
- Sawka M. Human Water Needs. Nutr Rev. 2005;63:S30-S39. doi:10.1111/j.1753-4887.2005.tb00152.x
- Bytomski J, Squire D. Heat Illness in Children. Curr Sports Med Rep. 2003;2(6):320-324. doi:10.1249/00149619-200312000-00007
- Cian C. Influence of Variations in Body Hydration on Cognitive Function. J Psychophysiol. 2000;14(1):29-36. doi:10.1027//0269-8803.14.1.29
- Ritz P, Berrut G. The Importance of Good Hydration for Day-to-Day Health. Nutr Rev. 2005;63:S6-S13. doi:10.1111/j.1753-4887.2005.tb00155.x
- Blau J. Water-Deprivation Headache: A New Headache With Two Variants. Headache: The Journal of Head and Face Pain. 2004;44(1):79-83. doi:10.1111/j.1526-4610.2004.04014.x
- Thomas D. Understanding Clinical Dehydration and Its Treatment. J Am Med Dir Assoc. 2008;9(5):292-301. doi:10.1016/j.jamda.2008.03.006
