337-OR: Hyperglycemia Lowers Lactate Clearance during Exercise in Type 1 Diabetes

To determine the role of hyperglycemia on lactate metabolism during exercise in type 1 diabetes (T1D), we studied 7 T1D participants during two visits (EuLoI; euglycemia, low insulin; HyLoI: hyperglycemia, low insulin) in random order. 7 nondiabetic (ND) subjects were studied on one occasion (EuLoI). Lactate turnover was measured using [1-13C] lactate before, during and after 60 min of exercise at 65% VO2 max. While lactate clearance was lower (p=0.031) during exercise at HyLoI than EuLoI in T1D, it was not different between T1D and ND subjects at EuLoI (p=0.707). In contrast, rate of lactate appearance during exercise was not different between EuLoI vs. HyLoI in T1D (p=0.129), demonstrating that higher plasma lactate concentration during exercise in HyLoI (p<0.001) was due to reduced lactate clearance in T1D. The results from this pilot study indicates that hyperglycemia modulates lactate metabolism during exercise by lowering lactate clearance in T1D individuals. This novel observation implies that exercise during hyperglycemia can lead to higher circulating lactate concentrations thus increasing the likelihood of reaching the lactate threshold sooner, in type 1 diabetes. Disclosure D.Romeres: None. Y.Yadav: None. F.Ruchi: None. R.Carter: None. C.Cobelli: None. R.Basu: Consultant; Sparrow Pharmaceuticals Inc, Research Support; Abbott Diabetes, AstraZeneca. A.Basu: None. Funding National Institutes of Health (DK29953 to R.B.), (DK85516 to A.B.)