The importance of physical activity in the management of diabetes is well established. The effect of programmed exercise and measurable skeletal activities on diabetes has been variously studied. Chorea induces an increase in spontaneous movement. Its occurrence in a teenager with type 1 diabetes provides new insights into our knowledge of metabolic outcomes. In our patient, the reduction in daily insulin demand was linked to choreic movement: a 67% decrease in insulin supply was needed to avoid episodes of hypoglycaemia; moreover, improved metabolism (measured as glycated haemoglobin) was obtained. Since no dietary changes were made and clinical events (including fever, drugs, weight loss, voluntary physical activity, psychological opposition or refusal of treatment) interfering with metabolic control of diabetes occurred, it appeared that only increased physical movements due to chorea reduced the patient's insulin requirement. As spontaneous movements declined with healing, metabolic control was lost, requiring an increase in insulin dosage to restore it. This article sheds additional light on our current understanding of hypoglycaemia and the variability of exogenous insulin demand in childhood and adolescent diabetes, when there are spontaneous movements and play. This finding highlights the importance of movement in type 1 diabetes.