We have previously shown that low insulin coupled with euglycemia or mild hyperglycemia appear to be the most favorable milieu for type 1 diabetes (T1D) during exercise. However, the contributions of insulin-dependent (IDGU) and insulin independent (IIGU) effects of exercise on glucose utilization are unknown. To do so, we studied 6 T1D (age 29±3 years, BMI 28.3±2.0 kg/m2, VO2 max 28.7±2.9 ml/kg/min, mean±SE) and 6 ND (age=28.2±4.2 year, BMI=23.6 ±1.0 kg/m2, VO2 max 36.6±2.9 ml/kg/min) subjects with a glucose clamp, during, before and after a 60 min exercise session at 65% VO2max, on three visits: euglycemia-low insulin (V1); euglycemia-high insulin (V2) and hyperglycemia-low insulin (V3) in random order. Glucose turnover was measured with the isotope dilution technique using [6,6-2H2]glucose. We modified the minimal model to measure the IDGU and IIGU components of glucose utilization (Figure 1, upper panel). Results demonstrate that while IDGU was similar in both groups (data not shown), IIGU (expressed as percent change from baseline) during exercise was significantly lower in T1D than ND subjects, though the trend across the visits were similar (Figure 1, lower panel). Further studies are necessary to determine the cause for this abnormality in T1D to optimize glucose control.

D. Romeres: None. M. Schiavon: None. A. Basu: Research Support; Spouse/Partner; AstraZeneca. C. Cobelli: None. R. Basu: Other Relationship; Self; AstraZeneca. C. Dalla Man: None.


National Institutes of Health (R01090541)

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