You probably already know that drinking enough water is pretty important. In fact, water makes up up to 60 percent of our bodies, per the United States Geological Survey (USGS) and is required for nearly every bodily function, from breathing and digestion to blood flow and physical endurance.
When you exercise, it’s especially important to be mindful of the amount of water that you drink, as it can be lost more easily when we are hot, sweaty and burning energy. “Not only is water the solution in which chemical reactions take place and nutrients and minerals are exchanged, but water is also essential for regulating body temperature, it keeps our eyes and nose moist and lubricates joints, it provides a mechanism for our kidneys and liver to dispose of waste, it softens our stool, and it protects our organs,” says Nicole M. Avena, Ph.D., Assistant Professor of Neuroscience at Mount Sinai School of Medicine and Visiting Professor of Health Psychology at Princeton University and author of What to Eat When You Want to Get Pregnant. “Every single organ system and cell in your body relies on water to survive.”
The question of whether or not we’re drinking enough water each day is one that most people have, especially because how much water you need depends on one of several factors, including your weight, the temperature of your environment, the level of physical activity you are performing and the amount of sweat you are producing.
The easiest way to tell whether or not you’re drinking enough water? Look at the color of your urine, according to Tony Castillo, M.S., R.D.N., L.D.N., co-founder of Nutrition for Performance and nutrition consultant for RSP Nutrition. “If you are well-hydrated, your urine will be a pale yellow or clear, and darker your urine, the more dehydrated you are,” he says. “Thirst is unfortunately not a good indicator because it is a sign that you aren’t getting enough water and are likely already slightly or moderately dehydrated.”
Because staying hydrated is so important, especially if you’re an avid exerciser, we reached out to top experts to unveil the key signs that you might not be drinking enough water.
You’re getting frequent headaches
Although a lot of things can cause headaches, mild-to-moderate dehydration is a common cause. “Not surprisingly, many people don’t realize that their headaches are a sign of dehydration, but drinking enough water is key to reducing a dehydration-related headache,” says Dr. Avena. “Ideally you want to make sure you are drinking enough water each day to avoid getting a headache in the first place and considering your environment and lifestyle to make sure you replenish lost fluids as necessary.”
You feel tired even after a good night’s sleep
Dehydration can make you feel tired regardless of how much rest you got the night before. What’s more: Being dehydrated can also impact your ability to get a good night’s sleep in the first place. “Like headaches, it can be difficult to pinpoint the reasons why we don’t always get good sleep or feel tired, but a good line of defense is to make sure you’re drinking enough water on a daily basis,” says Dr. Avena.
You’re super thirsty
“Being thirsty is your body’s primary warning system to let you know that you need water, so thirst can kick in once you’re only slightly dehydrated,” says Dr. Avena. If you feel thirsty, the best thing you can do is drink water.
She recommends making it a habit to drink water throughout the day so you don’t get to the point where it’s difficult to quench your thirst.
Your urine is dark
If you pee and notice that the color is dark and more concentrated, especially if you are peeing less frequently throughout the day, you are likely dehydrated, notes Dr. Avena. “Checking out the color of your urine is an easy way to see if you need more water,” she says. “You’ll want to make sure it’s a light yellow or almost colorless, otherwise, drink up!”
Your skin is flushed
If your skin feels flushed and you feel your temperature rising, you are likely overheated, and in need of fluids. “It is important to recognize that drinking according to thirst may not be sufficient to replace fluids lost during exercise and/or hot external temperatures,” says Chelsea Rose Geyer, Certified Integrative Nutrition Health Coach from The Institute for Integrative Nutrition. “When you are dehydrated, you can no longer thermoregulate, likely worsening your symptoms of dehydration.” Her best advice if you’re feeling flushed while working out is to seek shade, ASAP. “Consider wrapping a cool, damp towel around your neck and start rehydrating, pronto,” she adds.
Constipation can be caused by several factors, but one of the most common and the most likely is dehydration. “If you aren’t drinking enough water, the large intestine soaks up water from your food waste causing your bowel movement to slow,” says Geyer. “Proper levels of water in your stool allow the stool to soften, which helps you to pass it easier.”
So how much water should you drink each day? About 15.5 cups for men and 11.5 cups for women, according to the U.S. National Academies of Sciences, Engineering, and Medicine. To reach this goal, Geyer suggests having a water bottle on hand to help ensure you are getting enough each day, even if you’re always on the go.