To evaluate exercise-related glucose and counterregulatory responses (CRR) in adults with type 1 diabetes with impaired awareness of hypoglycemia (IAH) using hybrid closed-loop (HCL) insulin delivery to maintain glucose homeostasis.Twelve participants undertook 45-min high-intensity intermittent exercise (HIIE) and moderate-intensity exercise (MIE) in random order. The primary outcome was continuous glucose monitoring (CGM) time in range (70-180 mg/dL) for 24-h post-exercise commencement.CGM time in range was similar for HIIE and MIE (median 79.5% [interquartile range 73.2, 87.6] vs. 76.1% [70.3, 83.9], = 0.37), and time with levels <54mg/dL post-exercise commencement was 0%. HIIE induced greater increases in cortisol ( = 0.002), noradrenaline ( = 0.005), and lactate ( = 0.002), with no differences in adrenaline, dopamine, growth hormone, or glucagon responses.PIAH adults using HCL undertaking HIIE and MIE exhibit heterogeneity in CRR. Novel findings were a preserved cortisol response and variable catecholamine responses to HIIE.