(Reuters Health) - For people with type 2 diabetes, exercising in water is just as effective at improving blood sugar as other types of workouts, according to a review of existing research.

People who face obstacles in getting to a gym or exercising outdoors should consider hitting the pool to meet their exercise goals, the authors write in Acta Diabetologica.

Exercise helps lower blood sugar levels, which is a primary goal for diabetes management, but it also contributes to positive changes in body composition, blood pressure and cholesterol, and helps increase overall quality of life, the study authors note.

But only about 30 percent of people with type 2 diabetes adhere to a traditional exercise program that includes walking, running or resistance training.

“Our research group has conducted several exercise studies in people who have type 2 diabetes. We noticed that some people could not participate in our land-based (e.g., walking) studies due to barriers such as joint pain,” lead author Normand Boule told Reuters Health by email.

“We then planned to do a study on alternate forms of exercise which could address some of these barriers. Aquatic exercise seemed to be a logical alternative,” said Boule, a physical education and recreation researcher at the University of Alberta in Edmonton, Canada.

But when Boule and his colleagues looked for prior studies on this topic, they were surprised to find that not many water-based exercise studies had been done with people with type 2 diabetes.

“These studies had few participants, making it difficult to fully understand how water-based exercise may benefit individuals with type 2 diabetes,” he said, so they decided to pool the results in a so-called meta-analysis for a bigger picture.

They drew on nine previously published studies that examined aquatic exercises and blood sugar levels in people with type 2 diabetes. The water-based exercises included water walking or running, water cycling and various types of water-based fitness classes.

Two studies compared water exercise to land-based exercise directly. The rest compared water exercisers to similar but sedentary people, or compared individuals to themselves before starting an exercise regimen and after eight weeks or more of water exercise.

The researchers found that after eight weeks, water exercisers had reduced a marker of long-term blood sugar levels known as HbA1C by the same amount as people doing land-based exercise.

In addition, after 8 to 12 weeks of water-based exercise, individuals may have improvements in blood pressure, cholesterol, and triglycerides, Boule said.

There are some limitations to the analysis. Most of the studies were short-term, so more research is needed to see how water exercises compare with land-based exercises over time, Boule’s team writes.

While this study may be sufficient to show improved blood sugars, it would be important to conduct longer-term studies for several reasons, Boule said.

“First, adherence to longer-term exercise interventions is challenging; and challenges with access to a pool (e.g., costs, distance, program availability, etc.) may make adherence even more difficult than for other activities such as walking,” he said.

The second reason for longer-term study may be particularly relevant to people with lower-body limitations to exercise, such as joint paint, he said.

“With a longer-term study, improvements in fitness and reductions in joint pain may translate to increases in the ability to be physically active in other ways, outside of the pool setting. If so, water-based exercise may further assist in improving quality of life outcomes such as mental health and physical function,” Boule said.

SOURCE: bit.ly/2w3evrs Acta Diabetologica, online July 10, 2017.