A single 75-minute session of brisk interval walking performed just once a week can trim belly fat and boost cardiovascular fitness as effectively as spreading the same exercise across three separate days, according to new research from the University of Hong Kong.
The study, published yesterday in Nature Communications, involved 315 adults living with central obesity and ran over a four-month intervention period.
Researchers at HKUMed’s School of Public Health discovered that participants who consolidated their weekly interval training into one session achieved reductions in body fat percentage, total fat mass, and waist circumference that matched those seen in a group exercising three times weekly.
The findings offer a potentially significant shift in how clinicians might prescribe physical activity to time-poor patients.
Abdominal fat has strong links to cardiovascular disease
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Abdominal fat poses a particular threat to health because of its strong links to cardiovascular disease, metabolic conditions, and elevated mortality risk.
Obesity itself is a chronic condition characterised by harmful accumulation of body fat, yet exercise — one of the most effective tools for managing it — proves difficult for many sufferers to sustain over time.
Conventional guidance typically recommends interval training on three days each week.
For those juggling professional demands, family obligations, or limited access to fitness facilities, that frequency can feel unachievable.
Earlier studies have indicated that so-called “weekend warrior” exercise patterns, where most physical activity is compressed into one or two days, can still yield meaningful health gains.
Until now, however, scant evidence existed on whether interval training specifically retained its effectiveness when concentrated into a single weekly bout.
The HKUMed team conducted their randomised trial between September 2021 and September 2024, recruiting Chinese adults aged 18 and above who were overweight with central obesity.
Participants were divided into three cohorts: one performing all 75 minutes of interval training in a single weekly session, another splitting the same total across three sessions, and a control group attending fortnightly health education classes lasting two and a half hours each.
Body composition was assessed using dual-energy X-ray absorptiometry at baseline, at 16 weeks following the intervention, and again at 32 weeks for follow-up purposes.
After 16 weeks, both exercise cohorts demonstrated comparable improvements.
Each group reduced total body fat mass, body fat percentage, and waist measurement, while also showing enhanced cardiorespiratory fitness relative to the control group.
Professor Parco Siu Ming-fai, who heads the Division of Kinesiology at HKUMed’s School of Public Health, stressed the real-world significance of the results.
“While thrice-weekly interval training remains a commonly recommended approach for the therapeutic management of excess adiposity, our findings show that once-weekly interval training offers similar benefits and represents a practical exercise strategy,” said Professor Siu.
Once-weekly interval training offers a practical exercise strategy for anyone short on time
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“For many adults with central obesity who struggle to balance work, study, family and other commitments, time constraints are a primary barrier to exercising multiple days per week.”
He urged a rethink of conventional prescriptions. “Instead of relying solely on high-frequency exercise prescriptions, once-weekly interval training can be considered a feasible and effective alternative,” Professor Siu added.
