Making Waves: Water Aerobics Can Help Reduce Weight and Waist Size

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A 10- to 12-week water aerobics intervention was effective for weight and waist reduction, especially in women and adults aged 45 years or older, according to research published in BMJ Open.

“Exercise is a highly effective method for weight management, but individuals with obesity and overweight are prone to severe bone and joint injuries during physical activity due to their weight,” wrote a group of international investigators. “Traditional land-based aerobic exercise methods increase musculoskeletal damage in obese patients.”

Therefore, the American College of Sports Medicine recommends water aerobics for patients with obesity to mitigate this risk while improving exercise adherence. The buoyancy of the water helps to reduce the joint injuries these patients are susceptible to.

The benefits of water aerobics on body composition have been demonstrated in people with overweight and obesity, including improved body mass index (BMI) among young adults with obesity, reductions in body weight and body fat percentage in a group of middle-aged adults after a six-week intervention, and reductions in leg and waist circumference in older adults (mean age 72 years) with overweight.

However, investigators noted the effects of this exercise on physical indicators have not been studied. To rectify this, they conducted a systematic review and meta-analysis using 10 randomized controlled trials (RCTs) involving 286 participants, assessing weight, body fat and other anthropometric measures.

Eligible studies were identified via a systematic literature search of databases including PubMed MEDLINE, Embase, Ovid MEDLINE, Scopus, Web of Science and the Cochrane Library. Ongoing RCTs were not included. RCTs that were written in English, recruited adult patients with overweight and obesity, included a water aerobics intervention (four or more weeks long) and a comparator group, and focused on body composition were considered for analysis.

Among the RCTs ultimately included, participants’ ages ranged from 20 to 70 years. Trials were conducted across the globe, including the United States, the Netherlands, Malaysia, Brazil and India, and were published between 2009 and 2021. Intervention periods ranged from six to 12 weeks and included a variety of water aerobics, such as water yoga, aqua jogging and aqua Zumba. Most studies required people to participate in three 60-minute sessions per week.

Water aerobics significantly reduced body weight (-2.69 kilograms) and waist circumference (-2.75 centimeters), with more pronounced effects in women and middle-aged/older adults. Other body composition changes were not statistically significant.

The subgroup analyses revealed longer trials (more than 10 weeks) were more effective at reducing body weight than shorter interventions.

Interestingly, previous research has shown water aerobics are effective at reducing body weight in older men with overweight. However, these results demonstrated significant reductions in women but not men. This may be due to the small number of men recruited into the study.

The certainty of evidence was moderate for body weight and waist circumference but low for other measures including BMI, lean mass, fat mass, waist-hip ratio and hip circumference.

The study design using RCTs strengthened the findings. However, investigators noted limitations including the short intervention duration (e.g., six weeks) of some trials coupled with small sample sizes and limited data. Additionally, some individuals dropped out of the trial halfway through the intervention period. There were also some differences in the age, sex and location of participants.

Investigators encourage future research to include diverse populations with larger sample sizes that investigate the long-term effect of water aerobics. They also suggest comparing the efficacy of water-based interventions with that of other exercise modalities.

“Water aerobics is an important form of exercise for overweight and obese people, offering significant benefits in improving body composition and overall health,” investigators concluded.