Hydration is important every day because it keeps you feeling and performing at your best. But it's even more critical to pay attention to fluid intake in hot temperatures, during extended air travel, vigorous exercise and after the occasional cocktail.
Water makes up about 60 percent of the human body and it's needed for important jobs such as regulating body temperature, maintaining healthy skin and joints, digesting food, and helping the brain function at its best. That's why losing just one to two percent of body fluids can impact physical performance and, more seriously, it can affect cognition. The good news is that with a little know-how, you can defend against dehydration.
How Much Fluid Should You Drink in a Day?
Like food, there is a ton of information available about hydration, but knowing what's well-grounded can be more difficult to discern. "We've all heard the 'eight glasses per day' rule, but that amount is only a general guideline and may not be enough fluid intake during more dehydrating environments or situations," explains Abbott research scientist Jennifer Williams, MPH.
The National Academy of Medicine recommends drinking more water daily to keep properly hydrated — 2.7 liters of fluid or 11.4 cups of water for women and 3.7 liters or 15.6 cups for men. Williams notes that fluid needs will vary depending on age and activity level, and adds that a variety of fluids can help with hydration, like water, tea, coffee or even milk. When you drink your fluids matters too, and Williams recommends hydrating before bed, upon waking and before, during and after vigorous exercise.
How Foods Help With Hydration
Hydration is not just about fluids, it's also about electrolytes and carbohydrates. On a normal day, you can typically get enough electrolytes in your diet, but that changes when you exercise vigorously in a hot environment, have the stomach flu or food poisoning or enjoy a few alcoholic drinks.
"In dehydrating situations," Williams explains, "you'll need a small amount of carbs (glucose) with your beverages to help transport the sodium and potassium molecules into the cells to help your body rehydrate."
The main electrolytes in hydration beverages such as Pedialyte are sodium, chloride and potassium, which are also present in some foods. If you're feeling thirsty and worried about your electrolyte intake, add a few extra shakes of salt to your food, indulge in some pretzels and eat some potassium-rich foods like bananas, cantaloupe, avocados, sweet potatoes or spinach.
Fruits and vegetables that are high in water, like lettuce, cucumbers or tomatoes, contribute to your daily fluid intake, and as a rule of thumb, about 20 percent of daily fluid requirements should come from food.
How to Tell If You're Properly Hydrated
Since both fluid recommendations and symptoms of dehydration vary from person to person, it's important to be able to measure hydration status beyond just what you drink. Luckily, there are a few easy techniques.
"The most accurate way to determine hydration status is to weigh yourself before and after a workout to see if you lose body water," Williams explains. "If you lost a pound, that's 16 ounces of fluid you need to get back into you."
Another simple test is to evaluate the color of your urine. A dark yellow to amber indicates dehydration, while a pale yellow means you're properly hydrated.
Watch for the Downsides of Dehydration
One of the best things you can do is to be aware of dehydration before it happens. Be conscious of situations that might cause or worsen dehydration, like heat, traveling on an airplane, intense outdoor activity or drinking alcoholic beverages, and the warning signs.
The effects of dehydration on the body might be as mild as a slight headache, but they can also be serious if left untreated over time.
Since the brain is about 85 percent water, dehydration can cause moodiness, lack of concentration, lightheadedness and fatigue. Loss of fluids and electrolytes can cause muscle cramping that hinders athletic performance, and even constipation can also be the result of chronic dehydration.
Your circulatory system suffers the impact as well. "Without being hydrated, your heart can't do its job," Williams explains. The combination of heat and dehydration can strain the heart, causing symptoms that may become severe, including palpitations, increased heart rate and weakness.
It's also important to keep an eye out for symptoms of dehydration in at-risk groups.
"Young children are more susceptible to dehydration," warns Williams. "They have a higher composition of water in their bodies to maintain and it's harder for them to articulate that they're thirsty." Older people who are on medications or who limit their fluid intake may also be more likely to experience dehydration.
Remember to Pre-Hydrate
To combat potential dehydrating circumstances, it's important to take precautionary measures.
Pre-hydration is an effective strategy. "If you have a long flight, a big race coming up or intend to spend your day outside, drink extra water in the hours before," suggests Williams.
Dehydration is important to guard against, but by being proactive, you can get ahead of it and stay feeling at your best.