Predictors of Exercise Performance in Type 1 Diabetes: The Role of Hypoglycaemia Fear, Glycaemic Control, and Vascular Health: A Retrospective Cross‐Sectional Study

AIM: Cardiorespiratory fitness is often impaired in individuals with type 1 diabetes. While physiological determinants have been studied, psychological barriers such as fear of hypoglycaemia remain underexplored. We hypothesised that glycaemic factors including HbA1c, diabetes duration, the presence of microvascular complications, and fear of hypoglycaemia, would predict lower exercise performance. METHODS: This retrospective cross-sectional single-centre study included adults with type 1 diabetes who participated in a multidisciplinary rehabilitation program at the University Medical Centre Groningen. Outcomes were oxygen uptake, power output and heart rate at ventilatory thresholds and peak exercise. Predictors included age, sex, BMI, smoking history, diabetes duration, HbA1c, microvascular complications and fear of hypoglycaemia. Analyses comprised group comparisons and stepwise linear regression. RESULTS: (β = -0.089), as well as power output and heart rate. Greater fear of hypoglycaemia predicted lower power output at second threshold (β = -21.95) and peak exercise (β = -28.97). Microvascular complications were linked to reduced heart rate at ventilatory thresholds, with stronger effects for multiple complications. CONCLUSION: Fear of hypoglycaemia, HbA1c and microvascular complications are key determinants of reduced cardiopulmonary exercise performance in type 1 diabetes, highlighting the need for integrated physiological and psychological interventions.