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

Abstract

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 × mmol/l vs 1974 ± 324 min × mmol/l; p = 0.002), and was similar between Sit Less and Exercise (Exercise: 1383 ± 194 min × 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.

Trial registration: Clinicaltrials.gov NCT02371239 FUNDING: : The study was supported by a Kootstra grant from Maastricht University Medical Centre+, and the Dutch Heart Foundation. Financial support was also provided by Novo Nordisk BV, and Medtronic and Roche made the equipment available for continuous glucose monitoring.

Keywords: Glycaemic control; Insulin sensitivity; Light-intensity physical activity; Lipid metabolism; Sedentary behaviour; Sedentary breaks; Standing; Type 2 diabetes; Walking.

Conflict of interest statement

Data availability statement

The datasets generated and/or analysed during the current study are available from the corresponding author on reasonable request.

Duality of interest

The authors declare that there is no duality of interest associated with this manuscript.

Contribution statement

BMFMD, HHCMS, NCS, AK, and MKCH conceived and designed the experiments. BMFMD, LvK and NS performed the experiments and enrolled patients. BMFMD and BW analysed the data. BMFMD wrote the first draft of the manuscript. BMFMD, HHCMS, NCS, AK, MKCH, LvK, NS and BW contributed to the writing of the manuscript. BMFMD, LvK and NS undertook data collection. All authors approved the final version of the manuscript. BMFMD and HCCMS are the guarantors of this work and take responsibility for the integrity of the data and the accuracy of the analysis.

Figures

Fig. 1

Study design. Each participant followed three activity regimens under free-living conditions, each lasting 4 days: (1) Sitting: 14 h sitting/day; (2) Exercise: 1.1 h/day of sitting replaced by moderate- to vigorous-intensity cycling; and (3) Sit Less: 4.7 h/day of sitting replaced by standing (2.5 h) and light-intensity walking (2.2 h), relative to time spent doing these activities in the Sitting regimen

Fig. 2

Mean 24 h glucose profiles during the last day of each activity regimen (n = 19 individuals). Solid line, Sitting regimen; dashed line, Sit Less regimen; dotted line, Exercise regimen

Fig. 3

(a) Twenty-four hour glucose iAUC during the last day of each activity regimen, (b) insulin resistance expressed as HOMA2-IR on the morning after each activity regimen, (c) duration of hyperglycaemia, and (d) maximal reduction in glucose level at 30 min during the last day of each activity regimen. Data are estimated means ± SEM (n = 19 individuals). *p ≤ 0.05, **p < 0.01 vs Sitting regimen; †, p ≤ 0.05 vs Exercise regimen