Hyperglycemia can occur when individuals with type 1 diabetes (T1D) perform high intensity interval training (HIIT). However, the reproducibility of the glycemic response to a HIIT session has not been definitively tested. Seventeen patients with T1D, all using insulin glargine 300 U/mL (Toujeo®) as basal insulin, were asked to perform four separate in clinic HIIT sessions in an overnight fasted state. HIIT consisted of two bouts of cycling at 90% peak power, separated by a series of ‘CrossFit’-type activities, spanned over a 25 min period (∼75-95% of maximal heart rate). Plasma glucose (YSI) was measured pre-exercise (-10 min) and at 5- and 15-min into the HIIT session, as well as at 5- and 15-min in recovery. A total of 64 HIIT sessions were compiled. Pre-exercise blood glucose levels were similar among the four HIIT visits (8.8 ± 1.0 mmol/L, mean SD), as were the rise in glucose levels in response to HIIT (+3.9 ± 1.6; +3.8 ± 1.8; +3.9 ± 2.3; +3.9 ± 1.5 mmol/L, in visits 1-4, respectively). In almost all occasions (63 of 64 sessions), HIIT produced a rise in glycemia, but the inter-individual responses did vary, ranging from -0.3 to +9.0 mmol/L. The change in glucose during HIIT was not influenced by the baseline glucose concentration and was predictable within an individual based on the measured response in visit 1 (composite correlation with post-exercise glucose rise among the four visits was 0.56 [0.33-0.79, 95% CI]). Following HIIT, there appears to be a consistent increase from the pre-exercise glucose concentration in patients living with T1D and the degree of response is moderately reproducible within a given patient. Individualized insulin correction strategies, which take into account the rise in glucose observed and the patient’s sensitivity to insulin, may be helpful in restoring glucose control after HIIT in patients living with T1D.


M. Riddell: Speaker's Bureau; Self; Medtronic. Consultant; Self; Eli Lilly and Company, JAEB Center For Health Research, Xeris Pharmaceuticals, Inc.. Research Support; Self; Insulet Corporation. Speaker's Bureau; Self; Insulet Corporation. Advisory Panel; Self; Sanofi. Speaker's Bureau; Self; Ascensia Diabetes Care. Stock/Shareholder; Self; Zucara Theraputics. Other Relationship; Self; JDRF. R. Pooni: None. R.E. Brown: None. L. Yavelberg: None. Z. Li: None. C. Kollman: Research Support; Self; JDRF, Bigfoot Biomedical, Dexcom, Inc., Tandem Diabetes Care, Inc., Medtronic MiniMed, Inc., Helmsley Charitable Trust. R. Aronson: Other Relationship; Self; Novo Nordisk Inc., Janssen Pharmaceuticals, Inc., Sanofi, AstraZeneca. Research Support; Self; Eli Lilly and Company, Becton, Dickinson and Company, Merck & Co., Inc., Senseonics, Boehringer Ingelheim Pharmaceuticals, Inc..

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