Aim: This observational study examined in-ride interstitial glucose data and nutritional intake in a UCI-accredited professional cycling team with type 1 diabetes (T1D) over a nine-day training camp.
Methods: Sixteen male professional road cyclists with T1D (age 27±4 years, T1D duration 11±5 years, BMI 21.6±1.5 kg·min-2, HbA1c 6.8±0.6 %, O2max 71.3±3.9 ml·kg·min-1) on multiple daily injections performed eight rides over nine days lasting between 2 and 6 h, traversing 56 to 182 km/day. Cycle glycemic information (G6, Dexcom) was collected, stratified into glycemic time in ranges; hypoglycemia (Level 1: 54-70, Level 2: <54 mg/dL), euglycemia (71-180 mg/dL) and hyperglycemia (Level 1: 181-299, Level 2: >299 mg/dL) and analyzed for time spent (%) within each range. Nutritional intake during each ride was determined and reported as median (range).
Results: Average percentage time spent in euglycemia during cycling was 78±6% (daily range 70-86%). Hypoglycemia during cycling was 3±4% (range 0-11%, Level 1), and 1±2% (range 0-2%, Level 2). No hypoglycemic event required assistance. Percentage time spent in hyperglycemia during cycling was 17±7% (range 8-27%, Level 1), and 1±2 % (range 0-5%, Level 2). The contribution of carbohydrates, fat and protein to total in-ride energy intake was 83.8±15.4, 12.6±8.1 and 1.2±0.6 %, respectively. Macronutrient intake was dependent on cycle duration with greater carbohydrate intake rate on longer rides (2-hour cycle: 20 (4-82) g/h vs. 6-hour cycle: 51 (17-86) g/h).
Conclusions: Professional cyclists with T1D maintained a large proportion of time in a euglycemic range during intense cycling sessions over a nine-day training period. The low occurrence of in-ride hypoglycemia, mostly at Level 1, suggests a protective role for consumption of carbohydrate-rich foods to maintain glycaemia, especially during longer rides. However, time spent in Level 1 hyperglycemia during cycling was notable and should be monitored.
O. McCarthy: None. O. Moser: Research Support; Self; Abbott, Dexcom, Inc., Novo Nordisk A/S. M.L. Eckstein: Research Support; Self; Novo Nordisk A/S. S.N. Scott: None. M. Riddell: Advisory Panel; Self; Xeris Pharmaceuticals, Inc. Consultant; Self; Lilly Diabetes. Research Support; Self; Dexcom, Inc., Insulet Corporation, Novo Nordisk Inc., Sanofi. Speaker’s Bureau; Self; Medtronic MiniMed, Inc., OmniPod. Stock/Shareholder; Self; Zucara Therapeutics Inc. M. Fisher: Advisory Panel; Self; AstraZeneca, Boehringer Ingelheim International GmbH, Mylan, NAPP Pharmaceuticals Limited, Novo Nordisk A/S. Speaker’s Bureau; Self; Eli Lilly and Company, Sanofi. F.Y. Fontana: None. K. Skroce: None. L. Festa: None. P.H. Lagrou: None. P. Southerland: Other Relationship; Self; Novo Nordisk Inc. C.A. Hayes: Other Relationship; Self; Novo Nordisk A/S. M.P. Christiansen: Research Support; Self; Abbott, Biolinq, Dexcom, Inc., Eli Lilly and Company, Janssen Pharmaceuticals, Inc., Medtronic MiniMed, Inc., Novo Nordisk A/S, Sanofi-Aventis, Xeris Pharmaceuticals, Inc. B.W. Bode: Consultant; Self; ADOCIA, Lexicon Pharmaceuticals, Inc., Novo Nordisk Inc. Research Support; Self; Becton, Dickinson and Company, Dexcom, Inc., Diasome Pharmaceuticals, Inc., Eli Lilly and Company, Eyenuk Inc., Insulet Corporation, National Institutes of Health, Novo Nordisk Inc., Sanofi Research & Development, Senseonics, Xeris Pharmaceuticals, Inc. Speaker’s Bureau; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Janssen Pharmaceuticals, Inc., Novo Nordisk Inc., Sanofi US, Senseonics. Stock/Shareholder; Self; AgaMatrix, Glytec, LLC. C. Stettler: None. R.M. Bracken: None.