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Background: Active interruptions to sitting time are beneficial for glycemic control in adults with type 2 diabetes. With recent movements towards less prescriptive physical activity and sedentary behaviour guidelines, it is relevant to determine whether the frequency of interruptions to sitting time is important for health. The optimal frequency of active interruptions to sitting time is yet to be examined when total activity time is standardized. Purpose: To examine whether the frequency of interruptions to sitting time involving simple resistance activities (SRAs), compared to uninterrupted sitting, differentially affected 22 h glycemic control in adults with medication-controlled type 2 diabetes (T2D). Methods: Twenty-four participants (13 men; mean��SD age 62��8 years) completed three 8 h laboratory conditions: SIT: uninterrupted sitting; SRA3: sitting interrupted with 3 min of SRAs every 30 min; and, SRA6: sitting interrupted with 6 min of SRAs every 60 min. Flash glucose monitors assessed glycemic control over a 22 h period. Results: No differences were observed between conditions for overall 22 h glycemic control as measured by AUCtotal, mean glucose and time in hyperglycemia. During the 3.5 h post-lunch period, mean glucose was significantly lower during SRA6 (10.1 mmol.L-1, 95%CI 9.2, 11.0) compared to SIT (11.1 mmol.L-1, 95%CI 10.2, 12.0; P = 0.006). Post-lunch iAUCnet was significantly lower during SRA6 (6.2 mmol.h.L-1, 95%CI 3.3, 9.1) compared to SIT (9.9 mmol.h.L-1, 95%CI 7.0, 12.9; P = 0.003). Time in hyperglycemia was significantly lower post-lunch during SRA6 (1.5 h, 95%CI 1.0, 1.9, P = 0.001) compared to SIT (2.2 h, 95%CI 1.7, 2.6). Nocturnal mean glucose was significantly lower following the SRA3 condition (7.6 mmol.L-1, 95%CI 7.1, 8.1) compared to SIT (8.1 mmol.L-1, 95%CI 7.6, 8.7, P = 0.024). Conclusions: With standardized total activity time, less-frequent active interruptions to sitting may acutely improve glycemic control; while more-frequent interruptions may be beneficial for nocturnal glucose in those with medication-controlled T2D. Funding: This research was supported by a Heart Foundation Vanguard Grant (Award no. 101449), a NHMRC Centre of Research Excellence grant #1057608, and the Victorian Government OIS scheme., The Health & Fitness Journal of Canada, Vol. 14 No. 3 (2021): Proceedings from the 8th International Society for Physical Activity and Health Congress

OBJECTIVE: This study aimed to examine the effects on postprandial glucose and insulin responses of interrupting sitting time with brief bouts of simple resistance activities (SRAs) in adults with overweight or obesity. METHODS: Participants (n = 19) were recruited for a randomized crossover trial involving the following two 6-hour conditions: (1) uninterrupted sitting or (2) sitting with 3-minute bouts of SRAs (half-squats, calf raises, gluteal contractions, and knee raises) every 30 minutes (total duration = 27 minutes). Incremental areas under the curve (iAUC) for glucose, insulin, and insulin:glucose ratio were analyzed as prespecified secondary outcomes using mixed-effects log-linear regression adjusted for sex, BMI, treatment order, and preprandial values. Results are reported as multiplicative change (exponentiated coefficient [EC] with 95% CI) relative to the control condition. RESULTS: Glucose iAUC during the SRA condition was not significantly different from the prolonged sitting condition (EC = 0.92; 95% CI: 0.73-1.16; P = 0.43). However, SRAs lowered the postprandial insulin response by 26% (EC = 0.74; 95% CI: 0.64-0.85; P < 0.001), and there was a 23% lowering of the iAUC for insulin:glucose (EC = 0.77; 95% CI: 0.67-0.89; P < 0.001). CONCLUSIONS: In adults with overweight or obesity, frequent interruptions to sitting time with SRAs lowered postprandial insulin responses and insulin:glucose. These findings may have implications for mitigating cardiometabolic risk in adults with overweight or obesity who engage in prolonged periods of sitting.

Additional file 2. TIDieR checklist. Completed TIDieR checklist.

Additional file 4: Table 2. Participant concomitant medications.

Additional file 1. CONSORT Checklist. Completed CONSORT checklist.

Additional file 3: Table S1. Full inclusion and exclusion criteria.