Water is good, but are sports drinks better?

They come in exotic shades of green, red, orange and yellow with names promising athletic prowess.

They’re sports drinks—water-based beverages with added electrolytes and sugars—and athletes are increasingly choosing them over plain water during aerobic workouts.

But are sports drinks better than water?

The answer is "yes" for anyone doing an intense physical workout, according to several local physicians and trainers.

"In any kind of intense activity, you’re always better off with a sports drink rather than water," said Ketchum physician and nine-time Ironman competitor Greg Taylor. "The longer the activity, the more critical a sports drink becomes."

Sports drinks replace carbohydrates (which muscles burn) and electrolytes (which the body sweats out during exercise), Taylor explained.

Those who exercise moderately, such as playing a light game of tennis or round of golf, probably do not lose so much sodium through sweating to require replacement.

Water and a meal afterwards will replace lost nutrients and restore energy, according to Taylor.

"But for anyone exercising or training repetitively, a sports drink is an absolute necessity," Taylor said.

For those athletes, electrolytes—sodium, potassium, chloride—are not replaced by water alone.

"When you start filling with water and your sodium concentration drops, nasty things start to happen," Taylor said.

A condition called hyponatremia, characterized by muscle cramps and seizures, can be caused by a sodium deficit.

For competitive endurance events like the Ironman, water by itself is considered a poison, according to Taylor.

However, with sports drinks, electrolytes speed fluid from the gut into the bloodstream, making dehydration less likely.

In addition, electrolytes help stimulate the body’s thirst mechanism so that the athlete drinks more than normal.

Sports drinks also contain carbohydrates, which provide a steady source of energy.

"Muscles love to munch on carbohydrates," said Ketchum trainer Connie Aronson.

When muscle carbohydrate stores are depleted, athletes experience the feeling of "bonking" or "hitting the wall," Aronson said.

However, the higher the carbohydrate content of a drink, the more absorption, according to Aronson. Drinks containing more than 7-percent carbohydrates—such as fruit juices, soda drinks, and some sports drinks—are not recommended.

"For most athletes, a solution that includes some electrolytes works best," said another Ketchum physician Kathleen Haisley. "Plain water is usually not a good re-hydrating strategy as the only solution."

Haisley said that when she re-hydrates marathon runners after their 26.2 miles, she always uses solutions with electrolytes.

Aronson reminds her clients that water is still the nutrient they need to replace the most.

"You should drink throughout the day," Aronson said. "The body doesn’t let us know when it needs water. By the time you’re thirsty, you’re dehydrated."