The Pain-Reducing Power of Water Workouts

High intensity water workouts significantly reduce joint pain in adults with osteoarthritis, while improving mobility, balance and function, according to new study.

An estimated 27 million Americans have osteoarthritis, and research has shown that osteoarthritis in the knee is the leading cause of functional limitation among older adults.

Both increased muscle strength and reduced body weight have been shown to improve pain, says Eadric Bressel, a professor in the health, physical education and recreation department at Utah State University. Those suffering from joint pain, however, are often unable to do intense, muscle-strengthening and weight-loss-promoting workouts because of their symptoms.

“We had participants do high-intensity interval training, or HIIT, in the water,” says Bressel. “This same kind of high-intensity interval training on land would be unfathomable because of the load-elicited pain.”

(MORE: HIIT: One Way to Burn Fat and Lose Weight)

Intense Workouts With Achy Knees

For the study, published in the Journal of Strength and Conditioning Research, Bressel and his team had 18 participants with knee osteoarthritis complete a six-week, non-exercise control period where they didn’t do any specified training.

Following the control period, the researchers had the same participants complete an exercise program that included HIIT and balance training on an aquatic treadmill. Participants were immersed in water up to chest height while they exercised, and the team used water jets to add resistance and destabilize the participants while they walked. Participants reported high ratings of perceived exertion.

After the six week exercise period, participants reported significantly reduced joint pain and improved balance, mobility and function. No participants reported adverse effects, or exacerbation of pain or injuries. Based on the strength of their findings, researchers believe aquatic HIIT training may be effective at managing symptoms of osteoarthritis.

(MORE: 7 Ways to Pain-Proof Your Knees)

Adds Bressel: “Perceived pain was statistically reduced after each exercise session — and for a week afterward.”

Why Water Works

Water’s workout-boosting ability comes largely from its buoyancy. “When you stand in chest-high water, the buoyancy unloads 70 percent of your weight,” says Bressel. “It’s like being on the moon.”

If you weigh 164 pounds on land, for example, you would weigh the equivalent of 53 pounds in water — and with that much less weight to move, you can work out harder with less pain.

Water also confers hydrostatic pressure, or the gentle pressure of the water against the body. People with osteoarthritis often “have really bad balance and a really high fear that they will fall,” says Bressel, “but the hydrostatic pressure is like a security blanket around them, increasing their willingness to take risks in the water.” They may step out further than they normally would, for instance, or move faster than they would otherwise be comfortable moving.

(MORE: How to Get a Full Workout in the Pool, No Swimming Required)

Aquatic treadmills aren’t as common (yet) as pools or other gym equipment. Many major hospitals have them, says Bressel, as well as senior centers. And they’re nearly compulsory for major sports teams, who use them for injury rehabilitation. Says Bressel: “Any university with a Division 1 football team has one of these treadmills.”

If you have joint pain, it may be worth exploring nearby aquatic workout options (you can use a pool in some cases. See tips below).

“We’ve had a lot of subjective comments from patients who say, ‘This is the first time in years I’ve walked without pain,’” says Bressel. “That is pretty powerful to hear.”

3 Tips for Water Workouts

Want to reap the benefits of a water workout? Here’s some advice on getting fit in HO:

1. Use the deep end. If you don’t have access to an aquatic treadmill, you can improvise in the deep end of a standard pool. Use a flotation device to hold you up, says Bressel, and then mimic sprinting through water. He hasn’t tested this practice in a clinical setting, but, he adds, “It makes common sense that you would see similar benefits.”

2. Don’t go above chest height. When you wade into water deeper than chest high, you lose the ability to walk normally. When you’re doing intense training in H2O, keep the waterline at mid-chest. This applies in the deep end, too. Make sure the flotation device keeps your chest up.

3. Find a treadmill. “Using water to heal has been around since the Greeks and Romans,” says Bressel. “But we have less availability today, thanks to suing.” Aquatic treadmills are becoming increasingly common, however, especially in major cities. You might find one near you at a specialized fitness center, a rehabilitation or sports medicine clinic, a major teaching hospital or a University sports center.