Too Much Water? Or Too Little?

Bottle of Water by Maren Sederquist, MES, CSCS, PES, CPT

After being told we need to make sure we stay hydrated for most of our lives, this spring, headlines across the country warned us we could die of too much water! They were great headlines, but misleading. While the risk of hyponatremia – the potentially fatal lowering of sodium levels by diluting your blood – is real, dehydration is still far more common.

The New England Journal of Medicine published a study involving 488 runners who participated in the 2002 Boston Marathon (Volume 352:1550-1556, April 14, 2005, Number 15). A woman died during the marathon, after gulping 16 ounces of a sports drink. She’d already been running for five hours at mile 20. The study showed that the only few runners at risk for hyponatremia were those who were non-elite runners, with body mass index extremes, who gained weight while running, and had been running longer than 4 hours. While the risk is real, it is for a very limited percentage of the population.

We don’t hear of many people dying of dehydration because the dangers are so well known that they are taken care of. There are always tents full of people who are exhausted and have collapsed, getting IV fluids after endurance races. That's what saves their lives!

So, drink your water. Make it a sports drink to replenish electrolytes if you’re going to be exercising for longer than an hour, or if you’re a salty sweater. And weigh yourself before and after workouts to adjust your fluid intake, if you’re going to be exercising longer than a couple of hours.

If you feel thirsty, you may already be dehydrated, so drink up!

“Water makes up more than 70% of solid body tissue and helps regulate body temperature, carry nutrients and oxygen to cells, remove waste, cushion joints, and protect organs and tissues. Lack of adequate water intake leads to headaches, grogginess and dry, itchy skin. Severe dehydration affects blood pressure, circulation, digestion, kidney function, and nearly all body processes.” (

Symptoms of hyponatremia

Early Signs

Severe Sign

  • Post workout weight gain
  • Throbbing headaches
  • Bloating
  • Nausea
  • Grogginess
  • Brain Swelling

Symptoms of dehydration

(Even one sign can mean you’re dehydrated!)

Early Signs

Severe Signs

  • Fatigue
  • Headache
  • Appetite loss
  • Flushed skin
  • Heat intolerance
  • Light-headedness
  • Dark urine with a strong odor
  • Muscle cramps
  • Dulled thinking
  • Difficulty swallowing
  • Stumbling
  • Clumsiness
  • Shriveled skin
  • Sunken eyes and dim vision
  • Painful urination
  • Numb skin
  • Muscle spasms
  • Delirium
  • Fainting
  • Heart attack

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