Effects of breaking up prolonged sitting with light-intensity walking on postprandial glucose and lipid responses in sedentary adult men.

Prolonged sitting impairs postprandial metabolic regulation, but the optimal frequency and duration of light-intensity walking breaks remain unclear. This study compared two walking-break protocols on postprandial glucose metabolism, lipid responses, and substrate oxidation in sedentary adult men. Sixteen sedentary adult men (age: 37.44 ± 6.42 years; BMI: 28.82 ± 3.30 kg/m²) completed three 300-min conditions in random order, separated by ≥7 days: 4-min walking after 50-min sitting intervals (50SW), 2-min walking at 30-min intervals (30SW), and uninterrupted sitting (SIT). Walking was performed at 40-50% of age-predicted HRmax. Blood samples were collected before and 1-5 h after standardized test drink ingestion. Compared with SIT, glucose tAUC was reduced by 7.8% in 50SW and 6.4% in 30SW (p = .002), and insulin tAUC was reduced by 20.1% and 18.2%, respectively (p < .001). Triglyceride and most lipid responses did not differ significantly, whereas both walking conditions increased fat oxidation and decreased carbohydrate oxidation. No significant differences were observed between 50SW and 30SW. These findings suggest that less frequent walking breaks may provide comparable acute metabolic benefits and greater occupational feasibility.