The following article, originally posted on the nutritional sciences website, was shared by the CALS Wellness Committee with permission from the authors, Beth Olson and Tara LaRowe. Olson is an associate professor and extension specialist in the Department of Nutritional Sciences. LaRowe is an assistant teaching professor in the department.

With summer here, bringing warmer temperatures and outdoor activities, we need to pay attention to getting enough fluids. Water is an essential nutrient, making up about 50-60% of an adult’s body (65% for a child). It has many functions in our body, including regulating our body temperature, helping us remove waste from our body, providing lubrication to our joints and providing moisture to our tissues such as muscle and skin. It keeps our blood volume up and lets us move nutrients to all the cells in our body.

We “lose” water from our bodies every day and have to replace it to stay healthy. Nutritionists and other health professionals used to recommend people drink “8 glasses of water each day” and many people still remember this. However, this recommendation turned out not to apply to everyone, and we no longer use it. Instead, we say to “drink to thirst” —  i.e. drink when you are thirsty. However, research suggests that in the short term, people may not replace all the water they lose if they just drink when thirsty.

It’s important to remember that in addition to water we drink, we take in water through food (about 20% of our water each day) and through other beverages. It’s possible that the water in our food, drinking beverages with meals and drinking in other social situations work together with thirst to keep us hydrated. Current recommendations related to hydration are for fluid intake, with fluid = water + other beverages. For men, the recommendation is 13 cups/day, and for women, 9 cups/day. Recommendations are lower for children and teens. Surveys show adults consume about half of their beverages as plain water. Other sources of water include coffee and tea, juices or juice drinks, sugar sweetened beverages, and a wide variety of other beverages such as sports drinks and energy drinks.

There are times when “drinking to thirst” may not be enough. People may need to pay attention and drink more, even if not thirsty, if they are exercising for long periods of time or find themselves in hotter temperatures than that to which they are accustomed. Older adults are more likely to become dehydrated; they have less body water than younger adults, may have an impaired thirst mechanism, and may take medications that affect hydration. Signs of mild or moderate dehydration include thirst, dry mouth and headache; signs of severe dehydration include feeling dizzy, rapid heartbeat, or fainting. A common indicator of hydration status is urine color — well hydrated produces a pale yellow urine.

Caffeine in moderate amounts – particularly in amounts someone consumes on a daily basis – does not lead to dehydration. Alcohol intake may be dehydrating, especially in the short run.

With summer and hot weather here, and more outdoor activities, it is more likely people (including children, sometimes too busy playing to stop and drink!) will become dehydrated. Given water is about 1/3 of our beverage intake, we might consider increasing our water intake to ward off dehydration. Reusable water bottles carried along may encourage water intake. Adding fruit to water and keeping water cold may also encourage intake. People are more likely to drink water when it’s cool or cold, and some will consume more if the water is flavored.  Straws also seem to encourage drinking. Although we do recommend “drink to thirst,” during the heat and activity of summer, making a bit more effort to drink water is good advice.