Poster Presentation Australian Diabetes Society and the Australian Diabetes Educators Association Annual Scientific Meeting 2017

POSTER DISCUSSION: Current recommended carbohydrate intake prior to moderate intensity exercise with or without repeated sprints does not result in unphysiological glycaemic excursions in type 1 diabetes (#310)

Wayne Soon 1 2 3 , Kym Guelfi 2 , Liz Davis 1 3 4 , Paul Fournier 2 3 , Tim Jones 1 3 4
  1. School of Paediatrics and Child Health, The University of Western Australia, Perth, Western Australia, Australia
  2. School of Human Sciences, The University of Western Australia, Perth, Western Australia, Australia
  3. Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia
  4. Department of Endocrinology and Diabetes, Princess Margaret Hospital for Children, Perth, Western Australia, Australia

Introduction: Intermittent high-intensity exercise (IHE) is known to result in a lesser fall in blood glucose level (BGL) compared to continuous moderate intensity exercise (MOD) in individuals with type 1 diabetes mellitus (T1DM) under hyperinsulinaemic conditions. It is still unclear, however, whether moderate carbohydrate (CHO) intake prior to exercise performed in a basal insulinaemic state causes excessive hyperglycaemia during and after IHE. For this reason, our aim was to test the hypothesis that CHO intake prior to IHE and MOD causes an unphysiological rise in BGL in response to IHE, but not MOD.

 

Methods: After a familiarisation session during which VO2peak was determined, eight (5 females, 3 males) T1DM participants (age 14-35y, HbA1c 7.7±0.3%) in an overnight fasted and basal insulinaemic state completed on separate days the following 4 exercise sessions in a randomised counterbalanced order: MOD alone; MOD with prior CHO intake as per the 2016 ADA guidelines; IHE (MOD interspersed with a 4-s sprint every two minutes); IHE with prior CHO intake. At time intervals before, during and two hours after exercise, blood samples were taken to measure glucose and lactate levels. 

 

Results: In response to CHO intake, BGL increased by 1.8±0.6 (±SEM, p<0.02) and 2.3±0.3 mmol/L (±SEM, p<0.00) compared to pre-exercise levels during IHE and MOD, respectively, and remained above pre-exercise levels during the two-hour recovery period, with no differences between exercise modalities (p>0.05). Without CHO intake, average BGL did not fall below pre-exercise levels during and after either mode of exercise, but decreased below pre-exercise levels in some participants.

 

Conclusion: Under basal insulin conditions, moderate intensity exercise with or without repeated sprints does not result in a significant fall in blood glucose level.  ADA-recommended carbohydrate intake results in a moderate, but not unphysiological increase in blood glucose level during and early after both exercise modalities.