Stop Drinking So Much Water!

Arthur Siegel had a good summer. The Harvard Medical School professor convinced the organizers of a major marathon in Rio de Janeiro to listen to him.

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Thanks to Siegel’s lobbying, the race packets for the July race, with more than 10,000 participants, included information on how to drink safely during the long run.

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“Drink to thirst, do not drink to max,” said Siegel, a specialist on life-threatening complications associated with marathon running.

Contrary to the oft-heard advice to hydrate while sweating, medical opinion is swinging in the direction that too much hydration can be a health hazard.

“Drink to thirst, do not drink to max,” said Harvard Medical School professor Arthur Siegel.

In a new paper published this October, Siegel argues that drinking too much water during strenuous exercise can lead to illness, and — in middle-aged men — to a higher risk of a heart attack.

Siegel said that in strenuous, high endurance exercise, the body experiences what’s proverbially referred to as “hitting a wall” — a stress hormone is released and the kidneys hold on to the excess water.

Surprisingly, overhydration can be more common than dehydration.

“The symptoms are even similar — dizziness, change of mental state, loss of energy,” Siegel said.

“Overhydration is a common metabolic disorder,” said Tamara Hew-Butler, professor of exercise science at Oakland University in Rochester, Minnesota. “Our bodies are finely calibrated to hold the right balance of sodium. When we ingest a lot of liquid the cells swell up, and this can be dangerous.”

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Hew-Butler co-authored a 2013 study of ultra marathoners in Northern California and found that out of 669 runners who completed a 100-mile race, 19 percent were dehydrated and 35 percent were overhydrated.

Once sodium levels drop, the cells expand. The swelling is dangerous in the brain, because the hard casing of the skull causes potentially lethal pressure to build up. Less serious symptoms of overhydration include dizziness, confusion, and headaches.

Since 2002, when the numbers began to be tracked, there have been 14 fatalities due to over drinking at high-profile marathon events, and many more cases of young athletes falling sick after drinking too much after sports practice.

But Siegel’s study takes it one step further and looks at the impact on heart health in middle-aged men, even those with no history of heart disease.

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According to his data, the rate of cardiac problems associated with strenuous sport has increased 2.3 fold from 2005 to 2010. He has calculated that a man over the age of 29 has a 1 in 22,000 chance of having some cardiac events after a strenuous high endurance physical challenge like the marathon.

“Many more men run today. It’s like a badge of honor to run a marathon. The training is great for men, but if you’re a middle-aged man, I recommend you do the training but skip the race,” he said.