CC BY 4.0Henson, JosephEdwardson, Charlotte L.Celis-Morales, Carlos A.Davies, Melanie J.Dunstan, David W.Esliger, Dale W.Gill, Jason M. R.Kazi, AadilKhunti, KamleshKing, JamesMcCarthy, MatthewSattar, NaveedStensel, David J.Velayudhan, LathaZaccardi, FrancescoYates, Thomas2025-10-172025-10-1720202021-05-050195-913110.1249/MSS.0000000000002249https://hdl.handle.net/20.500.14802/22441Purpose To identify predictors of favorable changes to postprandial insulin and glucose levels in response to interrupting prolonged sitting time with standing or light-intensity physical activity. Methods Data were combined from four similarly designed randomized acute cross-over trials (n = 129; body mass index [BMI] range, 19.6–44.6 kg·m−2; South Asian = 31.0%; dysglycemia = 27.1%). Treatments included: prolonged sitting (6.5 h) or prolonged sitting broken-up with either standing or light-intensity physical activity (5 min every 30 min). Time-averaged postprandial responses for insulin and glucose were calculated for each treatment (mean ± 95% confidence interval). Mutually adjusted interaction terms were used to examine whether anthropometric (BMI), demographic (age, sex, ethnicity [white European vs South Asian]) and a cardiometabolic variable (Homeostatic Model Assessment of Insulin Resistance)-modified responses. Results Postprandial insulin and glucose were reduced when individuals interrupted prolonged sitting with bouts of light physical activity, but not with standing. Reductions in time-averaged postprandial insulin were more pronounced if individuals were South Asian compared with white European (−18.9 mU·L−1 [−23.5%] vs −8.2 mU·L−1 [−9.3%]), female compared with male (−15.0 mU·L−1 [−21.2%] vs −12.1 mU·L−1 [−17.6%]) or had a BMI ≥27.2 kg·m−2 (−20.9 mU·L−1 [−22.9%] vs −8.7 mU·L−1 [−18.2%]). Similarly, being female (−0.4 mmol·L−1 [−0.6 mmol·L−1, −0.2 mmol·L−1], −6.8% vs –0.1 mmol·L−1 [−0.3 mmol·L−1, 1 mmol·L−1], −1.7%) or having a BMI ≥27.2 kg·m−2 (−0.4 mmol·L−1 [−0.6 mmol·L−1, −0.2 mmol·L−1], −6.7% vs –0.2 mmol·L−1 [−0.4 mmol·L−1, 0.0 mmol·L−1], −3.4%) modified the postprandial glucose response. No significant interactions were found for Homeostatic Model Assessment of Insulin Resistance or age. Conclusions Being female, South Asian, or having a higher BMI, all predicted greater reductions in postprandial insulin, whereas being female and having a higher BMI predicted greater reductions in postprandial glucose when sitting was interrupted with light physical activity. These results could help to guide personalized interventions in high-risk participants for whom breaking prolonged sitting time with light activity may yield the greatest therapeutic potential.postprandialphysical activitysedentary behaviorrisk factorsinsulinglucoseJournal article2-s2.0-85085233736Published as ‘gold’ (paid) open accessOpenPUB0201081291NHMRC/1078360