More Time in Glucose Range during Exercise Days than Sedentary Days in Adults Living with Type 1 Diabetes

Michael C. Riddell, Zoey Li, Roy W. Beck, Robin L. Gal, Peter G. Jacobs, Jessica R. Castle, Melanie B. Gillingham, Mark Clements, Susana R. Patton, Eyal Dassau, Francis J. Doyle, Corby K. Martin, Peter Calhoun, Michael R. Rickels

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Objective: This study analysis was designed to examine the 24-h effects of exercise on glycemic control as measured by continuous glucose monitoring (CGM). Methods: Individuals with type 1 diabetes (ages: 15-68 years; hemoglobin A1c: 7.5% ± 1.5% [mean ± standard deviation (SD)]) were randomly assigned to complete twice-weekly aerobic, high-intensity interval, or resistance-based exercise sessions in addition to their personal exercise sessions for a period of 4 weeks. Exercise was tracked with wearables and glucose concentrations assessed using CGM. An exercise day was defined as a 24-h period after the end of exercise, while a sedentary day was defined as any 24-h period with no recorded exercise ≥10 min long. Sedentary days start at least 24 h after the end of exercise. Results: Mean glucose was lower (150 ± 45 vs. 166 ± 49 mg/dL, P = 0.01), % time in range [70-180 mg/dL] higher (62% ± 23% vs. 56% ± 25%, P = 0.03), % time >180 mg/dL lower (28% ± 23% vs. 37% ± 26%, P = 0.01), and % time <70 mg/dL higher (9.3% ± 11.0% vs. 7.1% ± 9.1%, P = 0.04) on exercise days compared with sedentary days. Glucose variability and % time <54 mg/dL did not differ significantly between exercise and sedentary days. No significant differences in glucose control by exercise type were observed. Conclusion: Participants had lower 24-h mean glucose levels and a greater time in range on exercise days compared with sedentary days, with mode of exercise affecting glycemia similarly. In summary, this study offers data supporting frequency of exercise as a method of facilitating glucose control but does not suggest an effect for mode of exercise.

Original languageEnglish (US)
Pages (from-to)376-383
Number of pages8
JournalDiabetes Technology and Therapeutics
Issue number5
StatePublished - May 2021


  • Continuous glucose monitoring
  • Exercise
  • Time in range
  • Type 1 diabetes
  • hyperglycemia
  • hypoglycemia
  • physical activity

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology
  • Medical Laboratory Technology


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