Effects of Sport-Specific, Intermittent High-Intensity Exercise on Post-Exercise Heart Rate Variability and Glycemia in Young Athletes with Type 1 Diabetes

Type 1 diabetes (T1D) is associated with hypoglycemia and premature autonomic disturbance (using heart rate variability [HRV]) - both which have been implicated in sudden death. This study examined the effect of a single bout of intermittent high-intensity exercise (IHE) on nocturnal HRV in ten hockey players with T1D and ten teammates without T1D. HRV and BG were analyzed from 12am-6am following hockey activity and low activity days. Hockey-type IHE on a cycle ergometer decreased BG by -1.9 ± 2.8 mmol/L, while an actual hockey game increased BG by 1.0 ± 3.2 mmol/L. One participant experienced nocturnal hypoglycemia after a hockey game (lasting 230 min). A significantly better nocturnal HRV profile (QTc, SDNN, pNN50, RMSSD) was observed following the low activity day compared to the days where IHE took place (p<0.05). There was no difference in HRV between T1D and non-T1D participants. This study documented the unique ability of a hockey game to increase BG in youth with T1D. Furthermore, given that decreased HRV is commonly noted in youth with T1D, this study suggests that the onset of autonomic hindrances can be delayed in highly-active individuals.