We’re always hearing how important it is to drink enough water.

Among other things, we’re told to down at least eight glasses of water per day and “to stay ahead of your thirst” before, during, and after exercise to avoid dehydration, which impairs performance and is harmful to your health.

Research shows we usually get enough water through foods (which supply about 20 percent of our water) and beverages (including coffee, soda, and alcohol)—and that for most of us, thirst is a reliable indicator of when we need more fluid, even during exercise.

I’m pretty sure no one likes the feeling of fluid sloshing around in their stomach mid-workout.  Or having to “run” to the bathroom every 5 minutes.  But staying hydrated during exercise is just as important as before or after exercise.

Why should you drink water during exercise?

  • Water regulates your body temperature.
  • It lubricates your joints.
  • It helps transport nutrients to give you energy and keep you healthy.
  • When you sweat, you are losing water and need to replenish your body with water.
  • If you’re not hydrated, your body can’t perform at its highest level. You may feel tired, have muscle cramps, dizziness, or other serious symptoms.

How much water should you be drinking during the day?

While the eight glasses rule is a good start, it isn’t based on solid, well-researched information.

Your body weight is made up of 60 percent water. Every system in your body needs water to function. Your recommended intake is based on factors including your sex, age, activity level, and others, such as if you’re pregnant or breastfeeding.


The current recommendation for people ages 19 and older is around 3.7 liters for men and 2.7 liters for women. This is your overall fluid intake per day, including anything you eat or drink containing water in it, like fruits or vegetables.

Of this total, men should drink around 13 cups from beverages. For women, it’s 9 cups.


Recommendations for kids have a lot to do with age. Girls and boys between ages 4 and 8 years should drink  five cups per day.

This amount increases to 7 to 8 cups, by ages 9 to 13 years. For ages 14 to 18, the recommended water intake is 8 to 11 cups.

During exercise, the average person ought to be drinking about a half a quart of water every 30 minutes, or a full quart in an hour, to replace the fluids they’re losing.   (If you’re worried you’re not drinking enough H20, monitor your urine. If it’s dark yellow, you need to drink more.)

What qualifies as hydrating?

Although water is the purest form of fluids to hydrate with, there are other fluids that will also do the job.

  • Milk: skim or whole. Drinking milk helped people retain a third of the fluid they consumed over a two-hour follow-up period, and remain hydrated for over four hours.
  • Hot or iced tea. …
  • Hot or iced coffee. …
  • Juice.

What happens to you when you dehydrate?

  •  Sweat may feel icky, but it has a very important purpose. Sweat is our body’s way of regulating it’s temperature and removing toxins and other unwanted compounds through the skin. When you’re too dehydrated to sweat, your body can’t cool down — in fact, your internal temperatures may continue to rise. If that happens, serious conditions like heat illness may occur.
  • If you get dehydrated, your body is going to pull water from your tissues, from your skin to maintain the concentration in your blood. When this happens, it leaves the skin drier and less elastic, leaving you looking much older.
  • Want to feel like you’re carrying around the Sahara Desert in your mouth? Cut back on your water consumption! A very common side effect of dehydration is a dry mouth. What that means is that water levels in the body are so low, your salivary glands can’t produce enough saliva. While the process may sound gross, it’s necessary for food digestion and for avoiding bacteria build-up — which can lead to another, more embarrassing problem.
  • When you pee, your body will try to tell you via the color of the liquid just how dehydrated you really are. Ideally, you’ll want urine that’s a pale, almost transparent shade of yellow. If your urine is notably dark yellow it could mean you’re slightly dehydrated. Orange or maple-colored urine often mean you’re very dehydrated.
  • Mild dehydration is a 1.5 percent loss in the body’s water volume. That might not sound like much, but researchers found that even being slightly off your proper hydration levels will affect a “person’s mood, energy level, and ability to think clearly.”
  • In addition to altering your mood, improper hydration may also physically alter your brain. Researchers have found that dehydration can affect the volume of brain structures, as well as shrinkage of brain tissue.
  • Proper hydration reduced the risk of a heart attack by as much as “54 percent in men and 41 percent in women.
  • When you’re feeling light-headed and disoriented due to dehydration that isn’t taken care of, what usually follows is your body’s sudden urge to be as close to the ground as possible — also known as fainting. When you become dangerously dehydrated, your body can experience a massive blood pressure drop. When that happens, it also means not enough oxygen-rich blood is getting to your brain, hence your loss of consciousness. 

Other things to consider…

You may also need to drink more water if you live in a hot climate, exercise often, or have a fever, diarrhea, or vomiting.

  • Add an additional 1.5 to 2.5 cups of water each day if you exercise. You may need to add even more if you work out for longer than an hour.
  • You may need more water if you live in a hot climate.
  • If you live at an elevation greater than 8,200 feet above sea level, you may also need to drink more.
  • When you have a fever, vomiting, or diarrhea, your body loses more fluids than usual, so drink more water. Your doctor may even suggest adding drinks with electrolytes to keep your electrolyte balance more stable.