When Maria Chan, a 45-year-old office worker in Hong Kong, tried to stick to the standard advice of exercising three times a week, life kept getting in the way. "I kept skipping sessions because of overtime and family duties," she said. But a new study suggests Maria might not need to stress so much about hitting the gym that often.
Researchers at the University of Hong Kong found that just one brisk interval walking session per week helped adults with belly fat — also called central obesity — lose body fat and boost heart health, nearly matching the results of people who worked out three times weekly.
The study, published in the journal Nature Communications, involved 315 Chinese adults aged 18 and older. All had central obesity, which means excess fat stored around the abdomen. This type of fat is particularly concerning because it raises the risk of heart disease, diabetes, and early death.
Participants were split into three groups. One group completed interval walking once per week. Another did the same total amount — 75 minutes weekly — but split across three sessions. The third group just attended health education classes and did not exercise. The researchers tracked body fat using detailed scans at the start, after 16 weeks, and again four months later.
The results surprised even the scientists. Adults who exercised just once a week reduced their total body fat, body fat percentage, and waist measurements nearly as much as those who exercised three times. Both exercise groups also improved their cardiorespiratory fitness — a key measure of heart and lung health.
Professor Parco Siu Ming-fai, who led the study, said the findings could open doors for people who feel exercise is out of reach. "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 explained. "Once-weekly interval training can be considered a feasible and effective alternative."
Interval walking, in this case, meant alternating between faster, more challenging bursts and slower, recovery-paced walking. This style of training has grown popular because it delivers strong results in less time compared to steady, moderate exercise.
The researchers conducted the randomized trial from September 2021 to September 2024 in Hong Kong. They used dual-energy X-ray absorptiometry — a highly precise scan — to measure changes in body composition. This attention to detail helped them confidently compare outcomes across groups.
Dr. Leung Chit-kay and Joshua Bernal served as co-first authors on the paper, contributing alongside Professor Siu's team at the School of Public Health.
Health experts have long worried that demanding exercise schedules push away the people who need help most. Roughly one in eight adults worldwide lives with obesity, and staying active is one of the most recommended strategies for managing it. Yet adherence rates remain low.
The study suggests that "weekend warrior" approaches — cramming weekly exercise into fewer sessions — may be more realistic without sacrificing benefits. For busy parents, shift workers, or anyone perpetually short on time, squeezing in a single 75-minute interval walk might be enough to start seeing real changes.
Of course, researchers caution that exercising more often may offer additional advantages not captured in this study. But for those who have tried and failed to keep up with multiple weekly workouts, one session is a start worth celebrating.