Water aerobics performed for more than 10 weeks can effectively reduce body weight and trim waist size in overweight and obese individuals, with particularly strong results in adults aged 45 and older, according to a new [study](https://bmjopen.bmj.com/content/bmjopen/15/3/e091743.full.pdf) published in _BMJ Open_.
Researchers analyzed data from 10 clinical trials involving 286 participants aged 20 to 70 from Malaysia, Brazil, India, the United States, the Netherlands and Iran. The exercises included water-based aerobics, Zumba, yoga and jogging, performed mostly two to three times weekly for 60-minute sessions over periods ranging from six to 12 weeks.
The results showed water aerobics led to an average [weight](https://www.mcknights.com/news/report-weight-resistance-training-may-help-older-adults-tackle-insomnia/) loss of nearly 3 kilograms (about 6.6 pounds) and reduced waist circumference by approximately 3 centimeters over the study periods of six to 12 weeks. The benefits were most pronounced in exercise programs lasting 12 weeks, with significant reductions observed specifically in women and those over age 45. There was insufficient evidence for significant effects on men or younger adults.
“Water/aqua aerobics for 10 or more weeks at a time can trim waist size and aid weight loss,” the researchers noted. The buoyancy of water helps reduce joint injuries commonly associated with land-based exercise in those who are overweight or obese, making it an accessible option for middle-aged and older adults.
While the intervention effectively reduced overall weight and waist circumference, it did not significantly impact body mass index (BMI), percentage body fat, fat tissue, waist-to-hip ratio or hip circumference in the overall analysis.
Using the standardized GRADE system to evaluate evidence quality, researchers rated the certainty of evidence as moderate for body weight and waist circumference outcomes, supporting water aerobics as an effective intervention for reducing overall body weight and central obesity.
The researchers recommended future studies with larger, more diverse populations and standardized methodologies to further investigate the long-term benefits of water aerobics compared to other exercise forms.