It’s heresy in the world of sports to belittle water, especially when we know the terrible impact of sugary sports drinks, sodas, and juices that try to replace it. But the fact remains that the prescribed 8 glasses a day and even more while exercising has murky origins and scant evidence to support it.
A Brief History of Dehydration
In the early 1970s the University of Florida Gators popularized a performance drink called Gatorade. As Gatorade grew, they funded research linking dehydration to poor heart health among athletes. Word spread fast in the athletic community, leading ultimately to the American College of Sports Medicine to release guidelines suggesting that athletes should “drink as much as can be tolerated.”(1)
The Rise of Hyponatremia
While there are no known deaths attributed to dehydration during marathons, there have been multiple deaths caused by overhydration, or hyponatremia. There were 21 reported cases of hyponatremia at the 2000 Houston Marathon alone.(2) Symptoms include swollen hands and feet, chest constriction, disorientation and fainting.
Hyponatremia was virtually unheard of among runners prior to the 1980s. In fact, today’s best performers don’t drink much water at all. Profligate water drinking is reserved for the slow-running masses, and those are the ones who suffer from the most hyponatremia. In contrast, world-class Kenyan runners rarely drink during races, and traditionally turn to a weak milk tea at night to replenish lost fluids.
How much water should we drink?
Our bodies are acutely aware of how much water we need. By listening to our bodies, we can strike the right balance. Drink when you’re thirsty. Drink water whenever your lips or eyes feel dry. Drink in the morning. But there’s probably no need to carry around a bottle of water all day long, and there’s certainly no need to punctuate every exercise with copious bouts of water drinking.
1. From The First 20 Minutes: Surprising Science Reveals How We Can: Exercise Better, Train Smarter, Live Longer by Gretchen Reynolds