Interrupting sitting time as a means to improve glucose metabolism in T2DM
Breaking sitting with light activities vs structured exercise: a randomised crossover study demonstrating benefits for glycaemic control and insulin sensitivity in type 2 diabetes.Literature - Duvivier BM, Schaper NC, Hesselink MK et al., - Diabetologia. 2016. doi:10.1007/s00125-016-4161-7
- Substitution of time spent sitting by ambulatory time reduced 24h glucose levels in the Sit Less regimen as compared with Sitting (mean [SEM]: 7.35 [0.19] vs. 7.69 [0.23] mmol/L, P=0.014). No significant difference was seen between the Sit Less and Exercise regimens (Exercise: 7.29 [0.24} mmol/L, P=0.741).
- iAUC provides a summary measure of the increase above fasting glucose level during the subsequent 24 h observation period. iAUC reduced significantly from 1974  min*mmol/L in the Sitting regimen to1263  min*mmol/L in the Sit Less regimen (P=0.002). Structured exercise reduced 24h glucose excursion to 1383  min*mmol/L), but this did not significantly differ from the Sitting regimen (p=0.069).
- Duration of hyperglycaemia over a 24 h time span was almost halved, from 211  min/day in the Sitting regimen, to 118  min/day in the Sit Less regimen (p=0.002). The Exercise regimen showed intermediate results with 152  min/day.
- Fasting insulin levels did not differ between the Exercise (102  pmol/L) and Sitting regimen ((108  pmol/L, p=0.117), but Sit Less showed significantly lower ((95  pmol/L) levels than Sitting. Likewise, Sit Less resulted in lower HOMA2-IR values than Sitting (1.89 [0.26] vs. 2.16 [0.26], P=0.001), and vs. Exercise (2.06 [0.28], P=0.015).
- An 0.5 MET x h/day difference was estimated between Exercise and Sit Less regimens. Energy intake did not differ significantly between the three regimens.
These data show that the Sit Less regimen improved insulin sensitivity, mean 24 h glucose levels, 24h glucose excursions, duration of hyperglycaemia and fasting triacylglycerol levels. In this study, the general effect of the Sit Less regimen on glucose homeostasis tended to be a little more potent than the effect of structured exercise. Insulin sensitivity was more improved after the Sit Less regimen than after the Exercise regimen. In this respect is it interesting to note that during the Exercise regimen participants spent most of the day sitting. It is thus proposed that the duration of non-sitting activities may be more important than the intensity of these activities.
The volume of light-intensity activities in this study was relatively high as compared with what is generally observed in T2DM patients, thus future studies may establish what activity regimen might be more feasible.