Post-exercise glycemic control in type 1 diabetes is associated with residual ꞵ-cell function
To investigate the impact of residual ꞵ-cell function on continuous glucose monitor (CGM) outcomes following acute exercise in people with Type 1 diabetes.
Research Design and Methods
Thirty participants with type 1 diabetes for ≥3 years were recruited. Firstly, participants wore a blinded CGM for 7 days of free-living data capture. Secondly, a 3 hour mixed meal test, assessed stimulated C-peptide and glucagon. Peak C-peptide was used to allocate participants into undetectable (Cpepund <3 pmol/L), low (Cpeplow 3–200 pmol/L) or high C-peptide groups (Cpephigh >200 pmol/L). Finally, participants completed 45 minutes of incline treadmill walking at 60%VO2peak followed by a further 48 hours’ CGM capture.
CGM parameters were comparable across groups during the free-living observation week. In the 12 (12hr) and 24 hours (24hr) post-exercise periods the Cpephigh group had significantly greater amount of time spent with glucose 3.9-10 mmol/L (12hr: 73.5±27.6%, 24hr: 76.3±19.2%) compared to Cpeplow (12hr: 43.6±26.1%, p=0.027, 24hr: 52.3±25.0%, p=0.067) or Cpepund (40.6±17.0%, p=0.010, 24hr: 51.3±22.3%, p=0.041). Time spent in hyperglycemia (12hr and 24hr glucose >10 and >13.9 mmol/L, p<0.05) and glycemic variability (12hr and 24hr SD, p<0.01) were significantly lower in the Cpephigh group compared to Cpepund and Cpeplow. Change in CGM outcomes from pre to 24hr post-exercise was divergent: Cpepund and Cpeplow experienced worsening (glucose 3.9-10 mmol/L: -9.1% and -16.2% respectively), with Cpephigh experiencing improvement (+12.1%)(p=0.017).
Residual ꞵ-cell function may partially explain the inter-individual variation in the acute glycemic benefits of exercise in individuals with type 1 diabetes. Quantifying C-peptide could aid in providing personalized and targeted support for exercising patients.