Once-a-Week Interval Walking Cuts Belly Fat as Well as Three Sessions, Study Finds
For busy modern adults, "lack of time" is often the top reason for skipping exercise. A new study brings good news: packing a week's worth of exercise into a single day may be just as effective for fat loss as spreading it across multiple sessions.
Researchers at the School of Public Health, LKS Faculty of Medicine, University of Hong Kong, conducted a randomized controlled trial involving 315 overweight adults with abdominal obesity. Participants were divided into three groups: a once-a-week exercise group, a three-times-a-week exercise group, and a control group receiving only health education. Both exercise groups completed a total of 75 minutes per week of high-intensity interval walking, alternating brisk walking with recovery walking. The once-a-week group performed three 25-minute sets in a single day, with 15-30 minutes of rest between sets.
Key Findings: Packing It In Works About as Well
After 16 weeks, body composition analysis showed that body fat mass fell by 2.6% in the once-a-week group and 3.5% in the three-times-a-week group — a difference that was not statistically significant. Compared with the control group, body fat declined by an average of 0.8 kg and 1.0 kg respectively. Reductions in waist circumference and improvements in cardiorespiratory fitness were similar in both groups.
"A lack of time is one of the biggest reasons adults fail to keep exercising," said Professor Parco Siu, who led the study. He added that once-a-week interval exercise can be a realistic and effective option. The findings are especially meaningful for office workers, students, and parents who find it hard to exercise several times on weekdays.
Important Caveats
This study does not suggest that exercising just once a week is sufficient. Both groups completed the same weekly total of 75 minutes — the comparison was about how the same amount of exercise was divided, not the number of sessions. Participants were limited to Chinese adults who rarely exercised, so the findings may not apply directly to other populations. Since visceral fat was not measured directly, it cannot be concluded that once-a-week exercise reduced visceral fat.
During 32 weeks of follow-up, the reduction in waist circumference was maintained, but the significant difference in overall body fat mass and body weight disappeared. The researchers explained that sustained physical activity is needed to maintain the effect.
Other Exercises to Improve Abdominal Obesity
- Strength training: Raises basal metabolic rate and helps reduce overall body fat. Since "spot reduction" is not possible, combining full-body strength training is effective.
- Low-impact aerobic exercise: Activities like swimming and cycling place less strain on joints and suit different fitness levels.
Managing waist circumference is as important as managing body weight. Abdominal obesity is directly linked to visceral fat accumulation and is a risk factor for diabetes, hypertension, dyslipidemia, and cardiovascular disease. Regularly monitoring waist circumference and weight is a key step toward better health. The Xiaoshu Health App can sync with Apple Health to track relevant metrics and help you manage your health data.