Drink when you’re thirsty, new study says

Too many runners are guilty of chugging water their bodies don’t need, say a group of medical researchers.

According to the study by doctors at Loyola University Medical Center, nearly half of recreational runners may be drinking too much during races. The news comes hot on the heels of a story about a 10K race in Wales that didn’t provide a water station at the halfway mark for runners.

The study found that nearly one-third of runners (29.6 per cent) incorrectly believe they need to ingest extra salt while running. And more than half (57.6 per cent) say they drink sports drinks because the drinks have electrolytes that prevent low blood sodium. In fact, the study found the main cause of low sodium in runners is drinking too much water or sports drinks.

Drinking too much fluid while running can cause a potentially fatal condition called exercise-associated hyponatremia. It occurs when runners drink even when they are not thirsty, which can dilute the sodium content of blood to abnormally low levels.

Instead, the study’s authors say drinking only when thirsty will prevent overconsumption of fluids. “It’s the safest known way to hydrate during endurance exercise,” says Loyola sports medicine physician Dr. James Winger, first author of the study.

Symptoms of hyponatremia can include nausea, vomiting, headache, confusion, loss of energy, muscle weakness, spasms or cramps. In extreme cases, the condition can lead to seizures, unconsciousness and coma.