The 'easy' fat-busting exercise that could help you shed half a stone in just 10 weeks
03/12/2025 12:31 PM
AN easy fat-busting form of exercise could trim your waist and help you shed half a stone in just 10 weeks, scientists say.
Women and people over the age of 45 reaped the most benefits from the workout, they found.
Water aerobics is often recommended to people who are overweight and obese, as being able to float in the water means they’re less likely to injure themselves while exercising.
Previous studies have shown that following the water-based workout for a number of weeks could help young people, as well middle aged and older adults, lose weight.
But the studies don’t show how exactly water aerobics may affect people’s body composition, a team of Chinese and Korean researchers said.
Their research, published in the journal BMJ, found that water aerobics lovers lost an average of 3 kilos – just under half a stone – and trimmed 3cm of their waists in a matter of weeks.
To find this out, scientists scoured through research databases for relevant studies published up to the end of 2021 that compared the effect of water aerobics to other types of exercise in adults who were overweight or obese.
Someone is considered overweight if they have a body mass index of 25 and over, while 30 and above is in the obese range.
The study team focused on 10 clinical trials that followed 286 participants in total, aged between 20 and 70 and living in in Malaysia, Brazil, India, the US, and the Netherlands.
People were randomly assigned different types of exercise, including aerobics, zumba, yoga, and jogging, for six to 12 weeks at a time.
The workout sessions happened two or three times as week and lasted an hour.
Researchers’ analysis showed that water aerobics were effective at reducing people’s body weight and waist circumference.
But it didn’t appear to have much of an effect on factors such as BMI, body fat percentage, people’s waist to hip ratio or hip circumference.
Water aerobics seemed to be particularly effective for overweight or obese women or people aged 45 and older.
For these groups, consistently exercising for more than 10 weeks was found to significantly reduce body weight by more than 3 kilos and waist circumference by nearly 3 cm.
While previous studies have suggested that water aerobics could help overweight older men shed weight, this wasn’t evident in this study – though researchers noted that this could due to the small number of men included in their analysis.
But the research did show that water aerobics could help shrink the waists of both men and women.
Researchers noted that some of the studies included in their analysis only included small numbers of participants – meaning it’s harder to generalise their findings.
In some cases, the studies only tracked participants for six weeks and researchers only looked at studies published in English.
They called for further studies on the subject, saying: "Future research should aim to address these limitations by conducting larger, well-designed randomised controlled trials with standardised methodologies and diverse populations.
How much exercise should you do and when?
There are guidelines issued by the NHS and the Government regarding how much exercise people should do each day.
People should be active daily, and avoid sitting for long periods.
The NHS recommends an adults – those aged 19 to 64 – should aim for 150 minutes of "moderate intensity activity" a week.
This works out to 21 minutes a day, or 30 minutes five days a week.
Or, they could do 75 minutes of vigorous activity per week, which could be less than 11 minutes per day or 25 minutes three days a week.
Adults should also aim to do strength exercises twice a week, at least.
Examples of moderate-intensity activities include brisk walking, water aerobics, riding a bike, dancing, doubles tennis, pushing a lawn mower, hiking or rollerblading.
Examples of vigorous activities include running, swimming, riding a bike fast or on hills, walking up the stairs, sports, like football, rugby, netball and hockey, skipping, aerobics, gymnastics or martial arts.
Things like lifting heavy weights, sprinting up hills, spin classes or circuit training are considered very vigorous.
What time should you exercise?
Getting exercise into your day, no matter what time is a good idea.
But you may want to be more selective depending on your goal.
A 2023 US study on 5,285 middle-aged adults showed exercising between 7 and 9 am was the best time if you’re looking to lose weight.
Researchers found that early-bird gym goers had a lower body mass index (BMI) and waist circumference than those working out later.
A 2022 study led by Prof Paul J Arciero, Skidmore College, New York, found that the optimal time of day to get your kit on might differ according to your gender.
Prof Arciero said women wanting to lose fat around their belly and hips would do better to hit the gym in the morning, but those seeking to gain upper body strength or simply improve their mood might see more results from evening exercise.
The results were the opposite for men.
If you struggle to get to sleep, it’s been found that exercise in the morning may help, but exercise in the evening may help you to stay asleep.
Exercise, generally, can improve sleep quality.
“Additionally, investigating the long-term effects of water aerobics and comparing its efficacy with other exercise modalities will provide valuable insights."
But researchers said their findings showed that water aerobics could be a helpful way for people to lose weight.
They wrote: “The moderate certainty of evidence for body weight and waist circumference supports the use of water aerobics as an effective intervention for reducing overall body weight and central obesity, which are critical factors in managing obesity-related health risks.
“In conclusion, water aerobics is an important form of exercise for overweight and obese people, offering significant benefits in improving body composition and overall health.”
Kenny Butler, health and wellbeing lead for the trade body ukactive, which represents gyms and leisure centres among others, said: “This study shows that pool exercises are particularly helpful for those living with obesity or joint injuries, and especially among women and older adults, where health inequalities are prevalent.
“Swimming pools in our leisure centres and gyms are safe, accessible places that are often closer to home than the hospital.
“These spaces provide an essential health service with plenty of effective options to choose from, including water aerobics, Zumba, yoga or jogging.”
He said encouraging people to exercise could “help reduce the demand on the NHS by keeping people off waiting lists”.
Previous research has shown that 150 minutes of exercise a week – which works out to 21 minutes across five days – is enough to help you lose weight and slash your risk of 19 diseases.
This is in line with NHS exercise guidelines.
Meanwhile, personal trainer and fitness journalist Lucy Gornall shared her top five exercises for weight loss.
