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Objective: This study examined acute effects of interrupting prolonged sitting with short activity breaks on postprandial glucose/insulin responses and estimations of insulin sensitivity in adults with type 1 diabetes (T1D). Method: In a randomized crossover trial, eight adults (age = 46 ± 14 years [mean ± SD], body mass index [BMI] = 27.2 ± 3.8 kg/m2) receiving continuous subcutaneous insulin infusion (CSII) therapy completed two 6-h conditions as follows: uninterrupted sitting (SIT) and sitting interrupted with 3-min bouts of simple resistance activities (SRAs) every 30 min. Basal and bolus insulin were standardized across conditions except in cases of hypoglycemia. Postprandial responses were assessed using incremental area-under-the-curve (iAUC) and total AUC (tAUC) from half-hourly venous sampling. Meal-based insulin sensitivity determined from glucose sensor and insulin pump (SiSP) was assessed from flash continuous glucose monitor and insulin pump data. Outcomes were analyzed using mixed models adjusted for sex, BMI, treatment order, and preprandial values. Results: Glucose iAUC did not differ by condition (SIT: 19.8 ± 3.0 [estimated marginal means ± standard error] vs. SRA: 14.4 ± 3.0 mmol.6 h.L−1; P = 0.086). Despite CSII being standardized between conditions, insulin iAUC was higher in SRA compared to SIT (137.1 ± 22.7 vs. 170.9 ± 22.7 mU.6 h.L−1; P < 0.001). This resulted in a lower glucose response relative to the change in plasma insulin in SRA (tAUCglu/tAUCins: 0.32 ± 0.02 vs. 0.40 ± 0.02 mmol.mU−1; P = 0.03). SiSP was also higher at dinner following the SRA condition, with no between-condition differences at breakfast or lunch. Conclusion: Regularly interrupting prolonged sitting in T1D may increase plasma insulin and improve insulin sensitivity when meals and CSII are standardized. Future studies should explore underlying mechanistic determinants and the applicability of findings to those on multiple daily injections. Trial Registration: Australian and New Zealand Clinical Trial Registry Identifier-ACTRN12618000126213 (www.anzctr.org.au). [ABSTRACT FROM AUTHOR]

Objective: To determine whether interrupting sitting with brief bouts of simple resistance activities (SRAs) at different frequencies improves postprandial glucose, insulin, and triglycerides in adults with medication-controlled type 2 diabetes (T2D).Research Design and Methods: Participants (n = 23, 10 of whom were female, with mean ± SD age 62 ± 8 years and BMI 32.7 ± 3.5 kg · m-2) completed a three-armed randomized crossover trial (6- to 14-day washout): sitting uninterrupted for 7 h (SIT), sitting with 3-min SRAs (half squats, calf raises, gluteal contractions, and knee raises) every 30 min (SRA3), and sitting with 6-min SRAs every 60 min (SRA6). Net incremental areas under the curve (iAUCnet) for glucose, insulin, and triglycerides were compared between conditions.Results: Glucose and insulin 7-h iAUCnet were attenuated significantly during SRA6 (glucose 17.0 mmol · h · L-1, 95% CI 12.5, 21.4; insulin 1,229 pmol · h · L-1, 95% CI 982, 1,538) in comparison with SIT (glucose 21.4 mmol · h · L-1, 95% CI 16.9, 25.8; insulin 1,411 pmol · h · L-1, 95% CI 1,128, 1,767; P < 0.05) and in comparison with SRA3 (for glucose only) (22.1 mmol · h · L-1, 95% CI 17.7, 26.6; P = 0.01) No significant differences in glucose or insulin iAUCnet were observed in comparison of SRA3 and SIT. There was no statistically significant effect of condition on triglyceride iAUCnet.Conclusions: In adults with medication-controlled T2D, interrupting prolonged sitting with 6-min SRAs every 60 min reduced postprandial glucose and insulin responses. Other frequencies of interruptions and potential longer-term benefits require examination to clarify clinical relevance. [ABSTRACT FROM AUTHOR]

Background: Postprandial glucose, insulin, and triglyceride metabolism is impaired by prolonged sitting, but enhanced by exercise. The aim of this study was to assess the effects of a continuous exercise bout with and without intermittent active interruptions to prolonged sitting on postprandial glucose, insulin, and triglycerides. Methods: Sedentary adults who were overweight to obese (n = 67; mean age 67 yr SD ± 7; BMI 31.2 kg∙m− 2 SD ± 4.1), completed three conditions: SIT: uninterrupted sitting (8-h, control); EX+SIT: sitting (1-h), moderate-intensity walking (30-min), uninterrupted sitting (6.5-h); EX+BR: sitting (1-h), moderate-intensity walking (30- min), sitting interrupted every 30-min with 3-min of light-intensity walking (6.5 h). Participants consumed standardized breakfast and lunch meals and blood was sampled at 13 time-points. Results: When compared to SIT, EX+SIT increased total area under the curve (tAUC) for glucose by 2% [0.1–4.1%] and EX+BR by 3% [0.6–4.7%] (all p < 0.05). Compared to SIT, EX+SIT reduced insulin and insulin:glucose ratio tAUC by 18% [11–22%] and 21% [8–33%], respectively; and EX+BR reduced values by 25% [19–31%] and 28% [15–38%], respectively (all p < 0.001 vs SIT, all p < 0.05 EX+SIT-vs-EX+BR). Compared to SIT, EX+BR reduced triglyceride tAUC by 6% [1–10%] (p = 0.01 vs SIT), and compared to EX+SIT, EX+BR reduced this value by 5% [0.1–8.8%] (p = 0.047 vs EX+SIT). The magnitude of reduction in insulin tAUC from SIT-to-EX+BR was greater in those with increased basal insulin resistance. No reduction in triglyceride tAUC from SIT-to-EX+BR was apparent in those with high fasting triglycerides. Conclusions: Additional reductions in postprandial insulin-glucose dynamics and triglycerides may be achieved by combining exercise with breaks in sitting. Relative to uninterrupted sitting, this strategy may reduce postprandial insulin more in those with high basal insulin resistance, but those with high fasting triglycerides may be resistant to such intervention-induced reductions in triglycerides. Trial registration: Australia New Zealand Clinical Trials Registry (ACTRN12614000737639). [ABSTRACT FROM AUTHOR]

Background: Sedentary behaviour is associated with impaired cognition, whereas exercise can acutely improve cognition.Objective: We compared the effects of a morning bout of moderate-intensity exercise, with and without subsequent light-intensity walking breaks from sitting, on cognition in older adults.Methods: Sedentary overweight/obese older adults with normal cognitive function (n=67, 67±7 years, 31.2±4.1 kg/m2) completed three conditions (6-day washout): SIT (sitting): uninterrupted sitting (8 hours, control); EX+SIT (exercise + sitting): sitting (1 hour), moderate-intensity walking (30 min), uninterrupted sitting (6.5 hours); and EX+BR (exercise + breaks): sitting (1 hour), moderate-intensity walking (30 min), sitting interrupted every 30 min with 3 min of light-intensity walking (6.5 hours). Cognitive testing (Cogstate) was completed at four time points assessing psychomotor function, attention, executive function, visual learning and working memory. Serum brain-derived neurotrophic growth factor (BDNF) was assessed at six time points. The 8-hour net area under the curve (AUC) was calculated for each outcome.Results: Working memory net AUC z-score·hour (95% CI) was improved in EX+BR with a z-score of +28 (-26 to +81), relative to SIT, -25 (-79 to +29, p=0.04 vs EX+BR). Executive function net AUC was improved in EX+SIT, -8 (- 71 to +55), relative to SIT, -80 (-142 to -17, p=0.03 vs EX+SIT). Serum BDNF net AUC ng/mL·hour (95% CI) was increased in both EX+SIT, +171 (-449 to +791, p=0.03 vs SIT), and EX+BR, +139 (-481 to +759, p=0.045 vs SIT), relative to SIT, -227 (-851 to +396).Conclusion: A morning bout of moderate-intensity exercise improves serum BDNF and working memory or executive function in older adults, depending on whether or not subsequent sitting is also interrupted with intermittent light-intensity walking.Trial Registration Number: ACTRN12614000737639. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Objective: To determine whether interrupting prolonged sitting with brief bouts of light-intensity walking (LW) or simple resistance activities (SRA) improves postprandial cardiometabolic risk markers in adults with type 2 diabetes (T2D).Research Design and Methods: In a randomized crossover trial, 24 inactive overweight/obese adults with T2D (14 men 62 ± 6 years old) underwent the following 8-h conditions on three separate days (with 6-14 days washout): uninterrupted sitting (control) (SIT), sitting plus 3-min bouts of LW (3.2 km · h(-1)) every 30 min, and sitting plus 3-min bouts of SRA (half-squats, calf raises, gluteal contractions, and knee raises) every 30 min. Standardized meals were consumed during each condition. Incremental areas under the curve (iAUCs) for glucose, insulin, C-peptide, and triglycerides were compared between conditions.Results: Compared with SIT, both activity-break conditions significantly attenuated iAUCs for glucose (SIT mean 24.2 mmol · h · L(-1) [95% CI 20.4-28.0] vs. LW 14.8 [11.0-18.6] and SRA 14.7 [10.9-18.5]), insulin (SIT 3,293 pmol · h · L(-1) [2,887-3,700] vs. LW 2,104 [1,696-2,511] and SRA 2,066 [1,660-2,473]), and C-peptide (SIT 15,641 pmol · h · L(-1) [14,353-16,929] vs. LW 11,504 [10,209-12,799] and SRA 11,012 [9,723-12,301]) (all P < 0.001). The iAUC for triglycerides was significantly attenuated for SRA (P < 0.001) but not for LW (SIT 4.8 mmol · h · L(-1) [3.6-6.0] vs. LW 4.0 [2.8-5.1] and SRA 2.9 [1.7-4.1]).Conclusions: Interrupting prolonged sitting with brief bouts of LW or SRA attenuates acute postprandial glucose, insulin, C-peptide, and triglyceride responses in adults with T2D. With poor adherence to structured exercise, this approach is potentially beneficial and practical. [ABSTRACT FROM AUTHOR]

Fatigue is a prevalent, costly and disabling clinical complaint among those with type 2 diabetes. In a randomized crossover trial, prolonged uninterrupted sitting increased fatigue by 29% relative to days when sitting was regularly interrupted by brief activity-breaks. This may have implications for diabetes-related quality of life, occupational productivity and self-care. [ABSTRACT FROM AUTHOR]