A blog by runners. For runners.

I’m supposed to run but … I feel dehydrated (practical running advice)

I'm dehydrated ... should I run?THE PROBLEM: If you wake up feeling excruciatingly thirsty, have a headache, and are kind of grumpy, you’re likely dehydrated. Symptoms of mild to moderate dehydration include:

  • Thirst
  • Headache
  • Dizziness
  • Weakness
  • Sleepiness
  • Feeling sluggish
  • Dry mouth and skin
  • Muscle cramps
  • Constipation
  • Not urinating as much as usual

Dehydration happens when you lose more fluids through sweating, urinating, having bowel movements, and breathing than you take in. Dehydration is more likely to happen in:

  • Endurance athletes. The longer you exercise, the more challenging it is to stay adequately hydrated. But dehydration can also happen during moderate activity. If you work out more than once per day, your risk may be greater because it can be more difficult to stay on top of your hydration needs.
  • Hot weather. You sweat more in hot and humid conditions. If you exercise in hot weather, your dehydration risk goes up even more.
  • High altitudes. Dehydration is more likely to occur above 8,200 feet.
  • People who are sick. If you have an acute gastrointestinal (GI) illnesses that causes vomiting and diarrhea, you can become dehydrated. People with chronic health conditions, such as diabetes or kidney problems, also have a higher risk.
  • People who are young or old. Infants, children, and seniors are the age groups most likely to suffer from dehydration.

SHOULD YOU GO RUN? No. Mild dehydration, when you lose about 1-2% of your body weight, usually doesn’t come with any serious, long-term risks when treated promptly. However, when you become more dehydrated than that, your risk of complications increases fast. Dehydration can lead to seizures, swelling of the brain, critically low blood volume, kidney failure, coma, and even death.

If you feel like you’re dehydrated, don’t run. Exercise will only cause you to sweat more and possibly cause you to become dangerously dehydrated.

TEMPORARY FIX: Drink up. If you’re mildly dehydrated, drinking water and sports drinks will help you to replace the lost fluids. However, if you’re severely dehydrated, seek medical help right away. You may need intravenous (IV) fluids to get fully rehydrated.

Don’t run until you’re adequately hydrated again. It make take a few hours to replenish the lost fluids or a full day.

PREVENT IT IN THE FUTURE: The best way to stop dehydration from happening again is to drink enough throughout the day and during exercise. Everyone’s hydration needs are different. For instance, people with a larger body size or a high sweat rate require more water than others.

There are several ways to tell if you’re taking in enough liquids or not. Try these methods:

  • Assess your thirst in the morning: If you wake up feeling extra thirsty, you’re likely mildly dehydrated.
  • Look at your urine: Check out the color of your urine every time you use the bathroom. Bright yellow to amber-colored urine means you’re dehydrated. Clear to pale yellow-colored urine means that you’re likely getting enough water.
  • Weigh yourself before and after your runs: If you weigh less after a run than you did before it, you didn’t take in enough fluids during your workout.
  • Drink when you feel thirsty: If you feel thirsty, drink up. It’s your body’s way of telling you that you need liquids, so don’t ignore it.

Written by Jen Matz /Photo Creative Commons

NOTE: This article is not a substitute for medical advice. Never run when you’re under the influence of alcohol, and never run when you feel dizzy, dehydrated, or sick.