Abstract

Background and aims: We have previously shown that interrupting prolonged periods of sitting with short, frequent light-intensity walking activity improves postprandial glucose levels in people with and at risk of Type 2 Diabetes. However, no research has investigated whether and how such an intervention affects postprandial glucose control, including the risk of hypoglycaemia, in people with Type 1 Diabetes (T1D). Therefore, we assessed the impact of short, frequent bouts of light-intensity walking on acute postprandial 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 fasted morning-time (~08:00am) laboratory visits each separated by a minimum of a 1-week washout. On each occasion participants consumed a standardised carbohydrate-based meal with their usual insulin dose determined by the carbohydrate-counting method; the meal and insulin dose was identical on each occasion. Following consumption of the meal, participants underwent two experimental conditions each lasting 4-hours: (1) uninterrupted sitting (SIT); or (2) sitting interrupted with 5-minute bouts of self-paced light-intensity walking every 30-minutes for a total of 4-hours (SIT-Less). Interstitial glucose responses were measured across the 4-hour postprandial period using continuous glucose monitoring (CGM).

Results: Postprandial glucose concentrations increased with SIT whereas this rise was tempered with SIT-Less (SIT: Δ2.7±2.6 vs. SIT-Less Δ0.4±1.2 mmol/L p=.043). With SIT-Less, Time in Range (3.9-10 mmol/L) was significantly increased (SIT 114±114 vs. SIT-Less 288±36 minutes p=.008), time spent in hyperglycaemia was significantly reduced (SIT 94±86 vs. SIT-Less 9.5±24 minutes, p=.043), and glucose peak was significantly lower (SIT: Δ5.8±4.1 vs. SIT-Less 2.0±1.4 mmol/L p=.047). There were no episodes of hypoglycaemia in either condition.

Conclusion: Interrupting sitting time, with brief regular bouts of light-intensity walking activity, significantly improves acute postprandial glycaemia in people with T1D without increasing the risk of acute hypoglycaemia. With low adherence to structured exercise and the ubiquity of sedentary behaviours, these preliminary findings suggest that interrupted sitting has the potential to be a safe, beneficial and practical means for improving postprandial glycaemia in people with T1D.