As temperatures in Dallas-Fort Worth reach into the 100s, staying hydrated becomes even more important. Last year, heat-related illness caused more than 350 deaths in Texas, a state record.
Our bodies cool themselves by sweating. When dehydrated, we stop sweating to conserve water, leading to an increase in body temperature and potential damage to our brains and other organs, said Cindy Trowbridge, an assistant professor of kinesiology at the University of Texas at Arlington.
To stay hydrated, here’s how much you should drink, what kinds of drinks you should avoid and what foods you should eat.
How much water should I drink?
How much water you need to drink depends on a variety of factors, including age, health, time spent outdoors and physical activity. A good baseline amount for a healthy adult is about eight 8-ounce servings, or about eight cups or glasses, Trowbridge said.
“It’s what you should always start off with,” she said. “You could probably even take those eight ounces and spread it to eight to 12 ounces throughout the day.”
Children 7 and younger should drink their age in 8-ounce cups of water, said Deborah Gillespie, an assistant professor of personalized health and well-being at the University of North Texas Health Science Center at Fort Worth. For example, a four-year-old would drink four 8-ounce glasses of water daily. Children 8 and older should follow the same guidelines as adults.
“The young, because they have a higher metabolic rate, do have a higher risk of getting dehydrated quicker,” Gillespie said.
Older adults are also at a higher risk of dehydration. As we age, we lose the ability to properly regulate our body temperature. And some medications that older adults take for high blood pressure or heart disease can affect how well they retain water.
For adults 51 and older, the National Academy of Medicine recommends drinking about 13 cups a day for men and nine cups a day for women.
To keep track of your hydration, Gillespie recommended the following:
- Use an insulated mug, pitcher or bottle with volume markers that help you see how much you’ve had.
- Incorporate hydration into your routine. For example, start drinking a full glass of water after brushing your teeth in the morning or drink two glasses with meals.
- Use a calendar, handwritten log or a water tracking smartphone app such as WaterMinder.
- Set phone alarms or reminders for when you need to dr ink.
Gillespie also recommended drinking water before, during and after outdoor physical activity, even if you’re only just sitting.
Water is important, but so are electrolytes
Water is usually the first choice for hydration. But there are other options that can help our bodies better retain fluids, said Brett Singer, a sports dietician at Memorial Hermann Rockets Sports Medicine Institute in Houston. These include beverages that contain electrolytes like sodium or nutrients like proteins, carbohydrates and fats.
Replenishing sodium is important because we tend to lose large amounts of this essential mineral when we sweat. Depending on temperature and physical activity, we can lose anywhere from 200 milligrams to 2,000 milligrams of sodium — or about a teaspoon’s worth of salt — in a liter of sweat, Trowbridge said.
“Ultimately, you need to replace that salt,” said Trowbridge, who recommends drinking beverages with sodium or eating a salty snack like peanuts to replenish what you’ve lost.
Watch out for caffeine and alcohol
Caffeine often gets a bad rap because it’s a diuretic, a substance that removes water from our bodies. But Gillespie said caffeine may not necessarily be dehydrating: It’s how much caffeine you drink that matters.
“The recommended cap per dietary guidelines is around 400 milligrams of caffeine a day. So it’s a little bit more than a cup and a half of coffee,” she said. “For a healthy adult with healthy kidneys, caffeine probably doesn’t have as much as a diuretic effect.”
Gillespie and Trowbridge recommend avoiding beverages with more than 400 milligrams of caffeine, especially energy drinks, which can contain 40 to 250 milligrams of caffeine per eight fluid ounces, according to the United States Food and Drug Administration.
Alcohol has a stronger diuretic effect than caffeine. It prevents the brain from making antidiuretic hormone, which regulates the body’s water levels, and thus causes more frequent trips to the bathroom and, by extension, possible dehydration.
“Drinking lots of alcohol can potentially set you up to be more dehydrated for the rest of the day, tomorrow, etc.,” Singer said. “The higher the alcohol concentration, the bigger the diuretic effect you’re going to see.”
What’s more concerning, Gillespie said, is that the signs of heat exhaustion or illness — such as dizziness and lack of awareness — can be very similar to those of alcohol intoxication.
If you are going to drink, Trowbridge and Gillespie recommended choosing beverages with low alcohol content and switching between alcoholic drinks and water or other hydrating drinks.
“It’s OK to have a beer after a marathon or after mowing the lawn, but then have a couple glasses of water,” Trowbridge said. “When I say beer, I’m talking about 3.2% to probably about 4 or 5% alcohol. It’s when you get into those spirits that have 15% to 40% alcohol content where it clicks off our [brain] and changes our ability to make decisions.”
Eat lots of fruits and veggies, but moderate sugar and protein consumption
Eating fruits and vegetables can help you stay hydrated, and some of these are more hydrating than others. Here are some examples:
- Melons like cantaloupes, watermelons and honeydew
- Berries, grapes, oranges and mandarins
- Cucumbers, tomatoes, celery, lettuce, zucchini, cauliflower and broccoli
For some of these vegetables, Gillespie said, eating them raw would be more hydrating. The next best way to have them would be steamed or lightly stir fried, so as to not lose too much water during cooking.
If you like dairy, Trowbridge recommended eating yogurt, which is a good source of vitamins, calcium and other minerals.
Avoid regularly consuming too much sugar, which can raise your blood sugar and lead to dehydration, Trowbridge said. According to the American Heart Association, men should consume no more than nine teaspoons of added sugar a day and women no more than six.
Low-carb diets can be dehydrating, Gillespie said, because they can force your body to break down its sugar reserves (called glycogen) for energy, losing water in the process. To stay hydrated, she recommended eating high-fiber, unrefined carbohydrates such as those found in fruits, vegetables, lentils and whole grains.
While eating protein isn’t dehydrating, consuming too much of it increases your body’s need for fluids to flush out the waste products associated with digesting proteins.
“Be aware if you are a person getting like one gram of protein per pound of body weight, or if you’re reliant on those protein shakes that can be upwards of 70 or 90 grams of protein,” Gillespie said. “Make sure you have plenty of fluid with that.”
Other ways to monitor your hydration
Thirst can be an indicator of hydration, but for some people it isn’t always reliable, especially for older adults, according to Trowbridge and Singer. This is because our body’s thirst signals weaken as we age.
Other signs to watch for are urine color and weight changes.
If you’re well-hydrated, your urine should be clear or the hue of light lemonade. Dark yellow means you’re dehydrated.
If your body weight dips below your usual baseline, that could be an indicator of dehydration.
“We usually say plus or minus 1% of your body weight is a normal fluctuation of hydration status,” Singer said. For instance, a 200-pound person’s weight may fluctuate between 198 and 202 pounds. Whatever your normal fluctuation is, Singer said, it’s important to stay within that range.
Miriam Fauzia is a science reporting fellow at The Dallas Morning News. Her fellowship is supported by the University of Texas at Dallas. The News makes all editorial decisions.