Water Adds Spice to Exercising : Health: Adapting regular workouts to the pool can burn up more calories with less stress.

The benefits of swimming are well-documented. One hour of the vigorous exercise can burn about 660 calories--the equivalent of jogging six miles in the same time. The problem is that counting laps can become boring.

Varying the routine with water walking or water jogging can perk up an otherwise repetitious pool workout. Water walking, which merely involves walking as fast as possible in water that is waist-high or chest-high, can burn more calories than water jogging, which is done in deep water.

“With water walking, you have some resistance because your feet are touching the bottom of the pool,” said John R. Spannuth, executive director of the United States Water Fitness Assn. in Boynton Beach, Fla. Water walking can burn up to 460 calories an hour, compared to water jogging, which can burn about 400.

Adapting land exercises to water, which uses the body’s natural buoyancy, makes moving less stressful and is particularly helpful for people recovering from joint or muscle injuries, said Jane Katz, professor of health and physical education at John Jay College of Criminal Justice at the City University of New York.

“In water, the body’s weight is about 10% of its true weight. The water supports all internal organs and relieves stress on the joints.”

The number of injuries that result from high-impact aerobics has contributed to the growing popularity of water exercise. An estimated 5 million people perform some form of vertical water aerobics, according to Jean Rosenbaum, a physician and director of the American Fitness Assn., a nonprofit research group based in Durango, Colo.

Water exercise particularly appeals to people over 35 who are sedentary, overweight or suffer from arthritis. “With water exercises, there is no impact to the body, and the injury rate is pretty close to zero,” Rosenbaum said.

Linda Huey, a Santa Monica-based kinesiologist, developed a “Waterpower Workout” to help clients control weight and build muscle strength. She starts her pool program with a 10-minute water stretch routine that works the major muscles, followed by a 45-minute basic workout.

“The majority of the American population are not good enough swimmers to get a decent workout,” said Huey. “Virtually everyone knows how to walk, and they can translate that to water.”