Hypoglycaemia is associated with increased cardiovascular and all-cause mortality in both subjects with and without coronary artery disease (CAD) [1]. Our group recently demonstrated that insulin-induced hypoglycaemia (IIH) is associated with a 14% reduction of myocardial blood flow reserve (MBFR) compared to baseline, in both healthy subjects and those with type 1 diabetes mellitus (T1DM) [2]. Cardiac troponin is a sensitive marker of myocardial injury and higher levels have been linked to adverse outcomes in patients with ACS [3]. A new ultrasensitive cardiac troponin I (us-cTnI) has been developed which has a limit of detection of at least one order of magnitude lower below that of current commercial assays. In comparison with current generation troponin assays, us-cTnI has been shown to be more sensitive in the detection of myocardial ischaemia. Furthermore, low but elevated levels of us-cTnI in patients presenting with suspected ACS, have been linked to adverse cardiovascular outcomes and death [4]. This study investigated whether 60 min duration of symptomatic IIH and reduction in MBFR, was associated with myocardial injury as determined by a change in serum levels of us-cTnI measured immediately following hypoglycaemia, in healthy and diabetic subjects without obstructive CAD.