Abstract

Background and aims: Interrupting prolonged periods of sitting with short, frequent light-intensity walking improves 24-hour glucose control Diabetologia in people with and at risk of Type 2 Diabetes. However, it is unknown whether and how such an intervention influences 24-hour glucose control, including risk of hypoglycaemia, in people with Type 1 Diabetes (T1D). Therefore, we evaluated the effect of short, frequent bouts of light-intensity walking on 24-hour glycaemia in people with T1D. Materials and methods: In a randomised crossover design, ten inactive adults with T1D (6 men; mean±SD: 30±34.7 years) completed two morning (~08:00am) laboratory visits in a fasted state, each separated by at least 1-week. On both visits, participants consumed a standardised carbohydrate-based meal with their usual insulin dose determined by the carbohydrate-counting method; the meal and insulin dose were identical on each visit. After consuming the meal, participants underwent two experimental conditions: (1) uninterrupted sitting (SIT); or (2) sitting interrupted with 5-minute bouts of light-intensity walking every 30- minutes for 4-hours (SIT-Less). Interstitial glucose responses were measured using continuous glucose monitoring (CGM) during the 4- hour laboratory visit for a further 20-hours under free-living conditions. Results: Compare to SIT, whole-day glycaemia was significantly lower following SIT-Less; 24-hour interstitial glucose Area Under the Curve was -14%[1.2%] under SIT-Less (p=0.023), accompanied by a significantly smaller average change in interstitial glucose from baseline (SIT: Δ1.5±2.5 vs. SIT-Less Δ-0.01±1.6 mmol/L, p=0.001), and lower average interstitial glucose peak (SIT:Δ7.7±3.0 vs. SIT-Less Δ3.9±1.4 mmol/L, p=0.002). Furthermore, with SIT-Less, Time in Range (TIR; 3.9-10 mmol/L), was significantly greater (TIR: SIT 991.5±286.86 vs. SIT-Less 1240.5±173.5 minutes, p=0.030), while time spent in hyperglycaemia was significantly lower (SIT 413.5±266.8 vs. SIT-Less 162±163.6 minutes, p=0.020). However, time spent in hypoglycaemia was similar between conditions (SIT 35±68.68 vs. SIT-Less 37.5±62.19 minutes, p=0.933). Glycaemic variability was lower with SIT-Less (CV%: SIT 29.4±7.6 vs. SIT-Less 22.1±7.5 %, p=0.021). Conclusion: Interrupting sitting time, with brief light-intensity walking activity, significantly improves whole-day glucose control in people with T1D. These preliminary findings suggest that interrupted sitting may serve as an effective and practical means of normalising daily glucose levels in people with T1D by increasing time in range and reducing glycaemic variability, without increasing the risk of hypoglycaemia.