Impact of 2-Month Exercise Training on Glycemic Metrics on Days with and without Exercise in Adults with Type 1...

Implementing exercise programs in individuals with type 1 diabetes may precipitate glycemic fluctuations. A better understanding of these fluctuations is essential for developing appropriate glucose management strategies. We aimed to assess glycemic excursions and their progression during a 2-month training program, comparing fluctuations around exercise sessions with those of non-exercising days.

Nineteen (13 female) adults with type 1 diabetes participated in two to three supervised 90-min combined (aerobic/strength) exercise sessions per week, over 2 months. Glycemic excursions (continuous glucose monitoring) were measured during specific periods (24-h, nocturnal; periods before, during, after exercise sessions) and compared between exercise and non-exercise days (linear mixed models, logistic regressions).

Nights following exercise sessions showed a reduced risk of hyperglycemia (>10.0 mmol·L -1 ) versus non-exercise nights. This difference diminished over the weeks of training, alongside a progressive increase in the risk of time >16.7 mmol·L -1 during the early and late recovery phases of exercise. Overall, regardless of exercise session occurrence, the risk of spending time < 70 or 54 mg/dL increased as the training program progressed.

Initially, acute exercise sessions reduced nocturnal hyperglycemia without increasing hypoglycemia. However, over time, the risk of nocturnal hypoglycemia increased, highlighting the need for vigilant glycemic supervision, particularly at night, even on non-exercise days.