Background: Aerobic exercise typically decreases blood glucose levels in individuals with type 1 diabetes. It is currently unknown if glucose responses to exercise and recovery differ between patients on multiple daily insulin injections (MDI) and continuous subcutaneous insulin infusion (CSII).
Subjects and methods: Nineteen (16 male, three female) physically active individuals with type 1 diabetes took part in this observational study. Interstitial glucose levels (blinded) were compared during 45 min of standardized aerobic exercise (cycling or running at 60% peak aerobic capacity) and during 6 h of postexercise recovery between individuals using MDI (n=9) and CSII (n=10) therapy.
Results: Both MDI and CSII groups had similar reductions in glucose levels during exercise, but responses in early and late recovery differed (group × time interaction, P<0.01). Participants using MDI had greater increases in glucose throughout recovery compared with individuals with CSII. Two-thirds of the MDI patients experienced late-onset post-exercise hyperglycemia (blood glucose >12 mmol/L) compared with only 1/10(th) of the CSII patients (P<0.01).
Conclusions: Among individuals performing regular moderate-to-heavy intensity aerobic exercise, use of CSII helped to limit post-exercise hyperglycemia compared with MDI therapy and is not associated with increased risk for post-exercise late-onset hypoglycemia.