Many patients with type 1 diabetes (T1D), avoid exercise due to the potentially large drop in blood glucose that is associated with moderate intensity continuous exercise and the associated risk of hypoglycaemia. Recent work from our laboratory suggests that, unlike moderate intensity exercise, high intensity interval training (HIIT) does not reduce blood glucose during exercise in people with T1D. Although this data provides promising evidence, more information is required on HIIT’s effects on daily glycaemic control. Therefore, the aim of this study was to determine the effects of HIIT on inter-day glycaemic control in people with T1D compared to moderate intensity continuous training (MICT) and no exercise at all. This study was provided with NHS research ethics before commencing. Participant’s with type 1 diabetes (Mean ± SD, n=2, Age 21.5 ± 0.7 years, Height 1.69 ± 0.01 metres, Weight 83.8 ± 3.6 kg, BMI 29.4 ± 1.6 kg/m2, T1D duration 12.3 ± 2.5 years) completed a randomised crossover study consisting of three 2-week interventions; 1) HIIT, 2) MICT and 3) a control intervention with no structured exercise training (CON). During the HIIT (6x1min intervals at >80% max heart rate) and MICT (30min at 60-70% max heart rate) interventions, six training sessions were completed. Throughout the 2-week intervention, glycaemic control was measured using an Abbot freestyle flash glucose monitor. Insulin dose, carbohydrate consumption and physical activity were also monitored throughout the intervention. During the 24-hour period after exercise, there were no significant differences (P > 0.05) in the mean number of hypoglycaemic episodes (HIIT 1.7, MICT 2.2) and the average time spent in level 1 (L1) and 2 (L2) hypoglycaemia (L1: HIIT 8.9%, MICT 7.2%; L2: HIIT 4.8%, MICT 2.1%) between the exercise interventions. Glycaemic variability, measured as standard deviation (SD) and coefficient of variation (CV) (SD: HIIT 3.7, MICT 3.4; CV: HIIT 42.9, MICT 41.7) was also not significantly different between interventions (P > 0.05). This is the first study to use the American Diabetes Association guidelines to assess glycaemic control following exercise in people with T1D. It is also the first study to measure carbohydrate consumption, insulin dose, and physical activity to provide a robust assessment of factors affecting glycaemic control in people with T1D. As such, this study has the potential to inform future guidelines on exercise for people with T1D. Due to the small sample size at this time-point, an overall conclusion cannot be determined for these results, however from the data collected; glycaemic control is similar across all interventions.