Adults with type 1 diabetes and cardiovascular autonomic neuropathy (CAN) showed altered responses to graded physical exercise. Results were presented at the European Association for the Study of Diabetes Conference 2025.

The study included 48 participants, with 24 adults with CAN and 24 matched controls without CAN. Participants performed a graded maximal exercise test while continuous cardiopulmonary monitoring recorded oxygen uptake and other performance metrics. Plasma adrenaline, noradrenaline, glucose, and lactate were measured every three minutes and at peak workload.

Participants with CAN had significantly lower peak oxygen uptake (19.6 vs 27.5 mL/kg/min) and reductions in other exercise performance and cardiopulmonary variables. Peak catecholamine concentrations and changes from rest to peak were also markedly lower in those with CAN (adrenaline Δ+0.13 vs Δ+0.32 ng/mL; noradrenaline Δ+1.33 vs Δ+2.33 ng/mL). Plasma glucose concentrations were similar between groups and remained stable throughout exercise.

The study concluded that autonomic neuropathy affects exercise capacity and sympathoadrenal responses but not glucose dynamics. These findings underscore the importance of assessing CAN for personalized training plans.