Hydration Myth-busters

Some of the received wisdom about hydration is not so wise


Posted: 23 November 2009
by Selene Yeager

Triathletes, like all athletes, need plenty of liquids to perform at their best. That inarguable fact is the easy part but things quickly become murky, because for years triathletes have heard conflicting reports about what, when and how much to drink before, during and after sessions. It's time to separate the facts from the fiction.

Myth 1: Replace every lost litre

For a long time triathletes have been told in stern tones to drink enough on the bike so that they weigh the same after the ride as they did beforehand. The truth is that your body cannot absorb fluids as quickly as it loses them, and, importantly, not every gram of weight is lost through sweat.

The Truth: Keep up with most of your sweat loss

Replace about 75 per cent of the fluid lost in sweat during a long ride. "To do that, you must know your sweat rate," says sport nutritionist Monique Ryan, author of Sports Nutrition for Endurance Athletes. To determine your sweat rate, weigh yourself before and after a short ride. "An hour-long ride is a good indicator of what you're losing through sweat alone," says Ryan.

Myth 2: Overflow before you go

Guzzling gallons before a run, ride or race will keep you topped up.

The Truth: Top up as you go

Drinking loads before a race will do little more than send you searching for loo stops. Sip a half-litre sports drink an hour or two before you exercise. That's enough time for your body to absorb what it needs and eliminate what it doesn't. Then take in about two to three gulps (up to 230ml) every 15 to 20 minutes while you train.

Myth 3: Caffeine will dehydrate you

Caffeine has long been demonised as a diuretic. That means it should lead to dehydration and heat stress, especially when you consider that it raises your heart rate and increases your metabolism.

The Truth: Caffeine improves carbohydrate burning

A review of ongoing research has shown that caffeinated drinks don't make you wee that much more than equal amounts of beverages without the buzz. Also, studies have shown that caffeine lowers your rate of perceived exertion while improving strength, endurance and mental performance. Even better, researchers from the University of Birmingham found that cyclists who drank a caffeinated sports drink burned the beverage's carbs 26 per cent faster than those who consumed a non-caffeinated sports drink - probably because caffeine speeds up glucose absorption.

Myth 4: More protein!

At first, carbohydrates were the building blocks of sports drinks. Then protein muscled its way in, after early studies showed that carb-protein blends seemed to shoot into the bloodstream and enhance performance better than carb-only drinks.

The Truth: You need a little protein...

Recent research on cyclists who performed an 80K trial showed that riders drinking carb-only beverages did just as well as those drinking carb-protein beverages. However, the International Society of Sports Nutrition recently reported that taking in branch-chained amino acids (BCAAs) during vigorous aerobic exercise can decrease muscle damage and depletion. "If you're on a long ride, where you're also eating, you'll be taking in protein already," says Ryan, "so it's likely not necessary to also have it in your drink."

Myth 5: Hydrate during all exercise

Beverage companies would have you grabbing your sports drink during every session, no matter how long or short the effort.

The Truth: Drink every day

"Your priority should be staying on top of daily hydration," says Ryan. Research on gym-goers found that nearly half began their workouts in a dehydrated state. "Many people don't consume enough fluids during the day," says Ryan. "If you hydrate properly, you won't need to worry as much about becoming dehydrated during a typical moderate ride." The old rule of eight glasses of water a day is a good guide.



 
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