Adults who condensed all 75 weekly minutes of high-intensity interval training into a single session lost about as much body fat over 16 weeks as adults who split the same minutes across three sessions. Both groups beat a control group that attended health education classes instead.
The randomized trial, published in Nature Communications on January 10, enrolled 315 inactive Chinese adults in Hong Kong with overweight and central obesity. It matters mainly for one reason: the most common barrier to exercise is time, and this trial tested whether frequency or total volume does the work.
