Breaking sitting with light activities vs structured exercise: a randomised crossover study demonstrating benefits for glycaemic control and insulin sensitivity in type 2 diabetes

Aims/hypothesis We aimed to examine the effects of breaking sitting with standing and light-intensity walking vs an energy-matched bout of structured exercise on 24 h glucose levels and insulin resistance in patients with type 2 diabetes. Methods In a randomised crossover study, 19 patients with type 2 diabetes (13 men/6 women, 63 +/- 9 years old) who were not using insulin each followed three regimens under free-living conditions, each lasting 4 days: (1) Sitting: 4415 steps/day with 14 h sitting/day; (2) Exercise: 4823 steps/day with 1.1 h/day of sitting replaced by moderate- to vigorous-intensity cycling (at an intensity of 5.9 metabolic equivalents [METs]); and (3) Sit Less: 17,502 steps/day with 4.7 h/day of sitting replaced by standing and light-intensity walking (an additional 2.5 h and 2.2 h, respectively, compared with the hours spent doing these activities in the Sitting regimen). Blocked randomisation was performed using a block size of six regimen orders using sealed, non-translucent envelopes. Individuals who assessed the outcomes were blinded to group assignment. Meals were standardised during each intervention. Physical activity and glucose levels were assessed for 24 h/day by accelerometry (activPAL) and a glucose monitor (iPro2), respectively. The incremental AUC (iAUC) for 24 h glucose (primary outcome) and insulin resistance (HOMA2-IR) were assessed on days 4 and 5, respectively. Results The iAUC for 24 h glucose (mean +/- SEM) was significantly lower during the Sit Less intervention than in Sitting (1263 +/- 189 min x mmol/l vs 1974 +/- 324 min x mmol/ l; p = 0.002), and was similar between Sit Less and Exercise (Exercise: 1383 +/- 194 min x mmol/ l; p= 0.499). Exercise failed to improve HOMA2-IR compared with Sitting (2.06 +/- 0.28 vs 2.16 +/- 0.26; p=0.177). In contrast, Sit Less (1.89 +/- 0.26) significantly reduced HOMA2-IR compared with Exercise (p= 0.015) as well as Sitting (p = 0.001). Conclusions/interpretation Breaking sitting with standing and light-intensity walking effectively improved 24 h glucose levels and improved insulin sensitivity in individuals with type 2 diabetes to a greater extent than structured exercise. Thus, our results suggest that breaking sitting with standing and light-intensity walking may be an alternative to structured exercise to promote glycaemic control in patients type 2 diabetes.