Water is critical for the human body, plus it allows all body systems to operate more efficiently and effectively. Since we lose water throughout the day, consistent intake is important in order for it to be available for its numerous functions in the body.
Adequate hydration is important for the brain, eyes, mucous membranes of the body, intestinal tract, urinary tract, skin, and most other tissues of the body. Consuming sufficient fluids can reduce the risk of urinary tract infections, kidney stones, and constipation.
Low fluid intake can also mean lower blood volume. This can lead to reduced transport of needed substances throughout the body and the removal of unwanted substances. It can also place more stress on the heart.
As part of our temperature control system, water is especially important when environmental temperatures and humidity rise, as occurs during the summer months. Our need for water also increases dramatically during physical activity, which tends to happen more during the warmer months of the year as well. When swimming or doing other summer activities in and around water (rivers, lakes, ocean), many people forget to consume adequate fluids. In these situations, fluid intake needs to be purposeful.
Also, some individuals have jobs outdoors and/or may wear clothing or equipment that increases sweating during the summer months, all of which can increase the risk of dehydration and related medical concerns. Adequate fluids should be made readily available in these situations.
The goal for everyone is to consume fluids consistently and in a timely pattern throughout the day. All liquids (water, milks, juices, soup, smoothies, tea, coffee, etc.) can contribute to fluid needs except alcoholic beverages. The frequency of urination and the color of the urine (should be light straw color) can be indicators of hydration status. Signs of dehydration can include thirst, dry mouth, headache, dizziness, confusion, unusual fatigue, unusual rapid heart rate, and in the extreme, no longer sweating in the heat.
In the case of athletes, the duration and intensity of physical activity, as well as the level of fitness of the individual, all affect the extent of the risk for dehydration. Adequate fluids should be consumed in the days/hours leading up to the activity, during the activity, and for several hours after the activity. For hydration purposes, carbonated and alcoholic beverages are not recommended during these times.
Consuming foods and/or fluids containing some sodium and potassium can assist the body in holding on to needed water and prevent concerning electrolyte imbalances. Note that some medications and medical conditions may warrant modification in this guideline.
When checking body weight before and after exercise, for every pound lost, 24oz. of water should be consumed above what had been consumed during the activity. Weight gain during activity would indicate too much water was consumed during the activity. The goal is not to lose or gain weight during this time.
Besides being a safety concern, dehydration caused by low fluid intake and increased sweating can reduce sports performance with as little as a 1 percent loss of body weight due to fluid losses. Greater than 3 percent loss is considered acute dehydration which can take days to recover. Extensive dehydration can lead a person down the path of heat stress, heat stroke, and in the extreme, even death.
Time spent at higher altitudes, especially when exercising, increases fluid needs. Hiking and mountain biking are examples of summer activities that may occur at higher elevations.
Planning for increased fluids needs is important in situations such as these when access to fluids may be limited.
Pregnant and breastfeeding women have higher fluid needs and should be especially purposeful in their fluid intake throughout the day, especially in warmer weather. Adequate water is needed to transport needed nutrients and oxygen, for the removal of waste products, for regulating the temperature of the fetus during pregnancy, for cushioning and protection of fetal tissues/organs, and other vital functions. Baseline daily fluid intake should be at least 96oz. a day during these situations.
The risk of dehydration is greater in children and in older adults. Children not only need more fluid relative to their body size, but also tend to ignore thirst cues and forget to drink. As we get older, our thirst mechanism becomes less efficient at telling us when we need more fluids. In addition, many older adults have concerns about urinary incontinence and will purposely consume less fluid throughout the day.
Other populations that may have a lower fluid intake are those whose job is inconvenienced by trips to the bathroom or have other obstacles to timely fluid intake. Teachers who cannot leave a classroom full of children may purposefully restrict fluids during the day. Persons working in hazardous situations or who are wearing gear or equipment that would make it difficult to consume fluids safely or conveniently are other examples of those at higher risk for dehydration.
So, be purposeful about consuming adequate fluids, especially in situations where higher intakes would be appropriate. Keep a water bottle or other container of fluid in sight and readily available. Set a timer on your phone or computer to remind you to take in fluids on a regular basis. Consider putting measured amounts of fluid in the refrigerator that you consume by certain time points during the day. If you have obstacles to taking in fluids consistently, consider ways to address these issues. By attending to your fluid needs, you can be at your best and medically safe during these hot summer months!
Pam Stuppy, MS, RD, CSSD, LD is a registered, licensed dietitian with nutrition counseling offices in York, ME and Portsmouth, NH. She is also the nutritionist for Phillips Exeter Academy, presents workshops nationally, and is Board Certified as a Specialist in Sports Dietetics. (See www.pamstuppynutrition.com for more nutrition information, some healthy cooking tips, and recipe ideas).