Which Comes First, Cardio or Weights_ - Alex Hutchinson [86]
Is it possible to hydrate too much?
In 2007, 28-year-old mother of three Jennifer Strange collapsed and died in her Sacramento home after taking part in a contest—“Hold your Wee for a Wii”—sponsored by a local radio station. The goal was to drink as much water as possible without going to the bathroom, with the winner earning a Nintendo Wii. Strange’s death was blamed on a condition called hyponatremia, sometimes known as water intoxication. Simply put, she had drunk so much that the levels of sodium in her blood were diluted, causing dangerous—and in this case fatal—swelling of the brain.
Over the last decade, medical directors at major marathons have sounded the alert about the dangers of overdrinking, thanks to about a dozen deaths at running races attributed to hyponatremia since the condition was first identified at the Comrades ultra-marathon in South Africa in 1981. Because the condition was so obscure, medical teams often mistook the symptoms for dehydration and pumped more fluids into collapsed runners, making it worse. Now that race personnel are aware of the dangers, these mistakes are less likely to occur.
Still, the condition is far more common than most people realize, since its first stages may not produce any obvious symptoms. Researchers at the University of London recruited 88 volunteers taking part in the 2006 London Marathon to give pre- and post-race blood samples in order to measure sodium levels. To their surprise, 11 of the volunteers (or 12.5 percent) developed asymptomatic hyponatremia, as indicated by abnormally low sodium levels—a particularly high number considering the cool and wet conditions of that year’s race, which discouraged excess drinking. As expected, the runners who developed hyponatremia drank more frequently during the race (typically every mile) compared with those who stayed healthy (typically every two miles).
None of the runners in the study suffered any ill effects, but the high prevalence of low sodium levels suggests that many runners are still aiming to drink as much as possible along the route. Those who take more than four hours to complete a marathon are thought to be at higher risk, because they have more time to ingest water. Even though sports drinks have sodium in them, there’s no evidence that they’re less likely to cause hyponatremia. The best solution is simply to avoid drinking too much—no more than about eight ounces every 20 minutes, according to some experts. Or according to others, only when you’re thirsty.
What ingredients do I really need in a sports drink?
If you’re an old-school type who thinks plain water is all you need, consider this puzzling fact: rinsing your mouth with a drink containing carbohydrates will boost your athletic performance, even if you don’t swallow and can’t taste the carbs.
Of course, it’s not just carbohydrates that you find in sports drinks these days. The latest offerings feature a bewildering array of formulations aimed at different sports and levels of activity, along with high-tech additives that purport to improve everything from alertness to metabolism. But you should be wary of the hype surrounding these magic ingredients. The core of any sports drink remains simple, says University of Guelph researcher Lawrence Spriet. Here are the three key ingredients, in order of importance:
• FLUIDS: The first point is simple: “If you’re engaging in physical activity you’re going to lose fluids,” says Spriet, who also serves as chair of the Gatorade Sports Science Institute’s Canadian advisory council. Although the precise link between dehydration and performance is still a topic of debate, it’s clear that letting yourself get thirsty during exercise will compromise your performance.
• CARBOHYDRATES: The second element is carbohydrates, which are typically