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TOPLINE: 

Breaking up long sitting periods with short, frequent bouts of light-intensity walks may reduce the increased levels of postprandial vascular inflammatory biomarkers seen in people with type 1 diabetes (T1D). 

METHODOLOGY: 

• A sedentary lifestyle, prevalent in patients with T1D, increases the risk for cardiovascular complications, but it is unclear whether reversing sedentary behavior modulates the thromboinflammatory milieu.
• The SIT-LESS study, a randomized crossover trial, included 32 people (mean age, 27.9 years; 17 women) with T1D who were on a stable insulin regimen and were classified as "inactive" by international guidelines on physical activity (< 150 minutes of moderate to vigorous physical activity per week).
• The participants completed two 7-hour laboratory visits separated by a gap of ≥ 7 days and either remained seated for the entire period in a reclining chair or interrupted sitting every 30 minutes by self-paced, of 3-minute light walks beginning 1 hour after each meal.
• Meals, insulin regimen, and step counts were recorded 48 hours before and after the first laboratory visit, and plasma levels of interleukin (IL)–1 beta, tumor necrosis factor (TNF) alpha, plasminogen activator inhibitor (PAI)–1, and fibrinogen were measured at baseline, 3.5 hours, and 7 hours.
• Insulin resistance status was determined using the estimated glucose disposal rate of < 8 mg/kg/min.

TAKEAWAY: 

• Prolonged sitting led to postprandial increase in TNF-alpha, IL-1 beta, PAI-1, and fibrinogen levels over time. In contrast, hourly 3-minute walks decreased these elevations, with all biomarker levels lower at 7 hours than at baseline (P < .001 for all).
• Over 7 hours, in people with prolonged sitting, TNF-alpha, IL-1 beta, PAI-1, and fibrinogen levels increased by 49%, 67%, 49%, and 62%, respectively; in people who undertook short walking breaks, the same markers dropped by 22%, 9%, 42%, and 44% (P < .001 for all).
• Individuals with high insulin resistance had a greater average reduction in PAI-1 levels (mean difference, -1.50 vs -0.38 pg/mL; P < .001) and fibrinogen level (mean difference, -3.78 vs -1.31 g/L; P < .001) than did those with low insulin resistance.

IN PRACTICE:

"Interrupting prolonged sitting with short, frequent bouts of light-intensity walking activity attenuates the deleterious rise in postprandial vascular-inflammatory parameters associated with prolonged sitting," the authors concluded. 

SOURCE: 

The study, led by Nawaz Z. Safdar, MBChB, Leeds Institute of Cardiovascular and Metabolic Medicine, Faculty of Medicine, University of Leeds, Leeds, United Kingdom, was published online in Diabetes, Obesity and Metabolism.

LIMITATIONS: 

This was a single-center study that excluded participants with overt complications. Whether the study was sufficiently powered to detect changes in the inflammatory marker levels is unclear. Moreover, the study could not provide insights on mechanisms supporting the findings owing to the short observational window.

DISCLOSURES: 

The study was supported by Diabetes UK. The authors declared no conflicts of interest.