The pool provides a safe environment for anyone who wants an intense cardio session, a gentle stretch or even some physical therapy. Water's resistance makes muscles work harder without putting stress on joints, and its buoyancy reduces musculoskeletal impact — making the pool ideal for anyone regardless of their age or fitness level. Now it looks like patients receiving rehabilitation following a stroke may benefit as well.
In a study that followed 21 patients recovering from a stroke, researchers found that they experienced better exercised performance when they walked on an underwater treadmill than when they walked on a conventional treadmill.
"Aquatic treadmill exercise may be a useful option for early intensive aerobic exercise after subacute stroke, as it may both improve their aerobic capacity and maximize functional recovery," according to Bo Ryun Kim, MD, PhD, and colleagues of Jeju National University Hospital, Korea.
The team reported its results in the American Journal of Physical Medicine & Rehabilitation, the official journal of the Association of Academic Physiatrists.
All 21 patients in the study had some walking ability, but had impaired leg movement on the side affected by the stroke.
The patients underwent two exercise tests — one on a conventional land treadmill and one on an aquatic treadmill, in which they were submerged in water up to their chests. In both tests, walking speed and slope were gradually increased until the patients felt they couldn't go any further.
Measures of exercise capacity were compared between the two tests. Two key measures were higher on the aquatic treadmill test: maximal oxygen consumption (VO2max), reflecting heart and lung function during exercise; and metabolic equivalents (METs), reflecting energy use. Heart rate was not significantly different, but was significantly related to oxygen consumption on both tests.
Even though their exercise performance was higher on the water treadmill, patients felt they weren't working as hard as on the land treadmill, based on a measure called rating of perceived exertion. "This improved performance may reflect the fact that the aquatic treadmill exercise involved the fluid resistance of the water environment," Dr. Kim and colleagues write.
Regaining walking ability is a major challenge after a stroke. Because it's so difficult to walk, patients tend to become inactive, which further reduces their exercise capacity. The longer they go without much physical activity, the harder it is to adopt even a gentle exercise routine. The team believes, therefore, that early intensive aerobic exercise training may be beneficial in the early weeks following a stroke.
Treadmill walking is actually often recommended, but may be difficult or impossible because of a patient's decreased muscle power. An aquatic treadmill would allow the patient to compensate for weaker muscles. It facilitates aerobic exercise without requiring full weight-bearing, the authors explain. And the best part is that patients are freed from the fear of falling.
This is the first study to explore the benefits of aquatic treadmill exercise for stroke patients, but additional research is needed to determine whether this approach leads to lasting improvements in exercise capacity and walking ability.
"Aquatic treadmill exercise may not only improve baseline functional status and functional recovery during the subacute period, but also enhance social participation and quality of life during the chronic stroke period," concludes Dr. Kim.