AimsExercise is an important practice for control in type 1 diabetes (T1D). This study aims to assess de association between exercise and glycemic management in people with T1D and to identify the main barriers to exercise in T1D.MethodsWe evaluated 95 people with T1D treated with insulin pump therapy. Participants answered a questionnaire about 1) exercise habits, 2) usual adjustments in insulin and food intake with exercise and 3) main barriers to exercise.Continuous glucose monitoring (CGM) was used to evaluate time in range (TIR), time below range (TBR) and time above range (TAR) during the last 60 days before the evaluation. CGM data during, before (2 h before) and after (24 h after) the last bout of exercise was also evaluated.ResultsThe mean age was 30.1 ± 12.1 years, and 51.6% were women. Participants that reported practicing exercise (55.8%) had a higher TIR (59.6 ± 16.3 vs. 48.7 ± 15.7,p= 0.012) and a lower TAR (32.6 ± 15.8 vs. 45.4 ± 17.7,p= 0.006). Comparing with the 60 days CGM data, the TBR was lower in the 2 h before exercise (− 1.8 ± 3.8,p= 0.0454) and TAR was lower during (− 16.9 ± 33.6,p= 0.0320) and in the 24 h after (− 8.7 ± 17.2,p= 0.032) the last bout of exercise. The absence of adjustments on insulin and food intake was associated with higher TBR after the exercise (13.44 ± 3.5,p< 0.05). Eating before the exercise and turning off the pump during the exercise were associated with lower TBR after exercise (food booster: − 7.56 ± 3.49,p< 0.05; turning off insulin pump − 8.87 ± 3.52,p< 0.05). The main barriers reported for exercise practicing were fear of hypoglycemia, lack of free time and work schedule.ConclusionExercise was associated with better glycemic management in people with T1D. Addressing common barriers may allow a higher adherence to exercise in T1D.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00592-023-02070-7.