Influence of Complications of Diabetes Mellitus on Exercise Tolerance of Patients with Heart Failure: Focusing on autonomic nervous activity and heart rate response during cardiopulmonary exercise tests

Purpose: The purpose of this study was to clarify the influence of complications of diabetes on the exercise tolerance of patients with heart failure. Methods: The subjects of this study were 69 patients (44 men; mean age: 62.2 ± 13.4 years) who were hospitalized and diagnosed with heart failure between November 2016 and November 2017. The subjects all took part in a cardiopulmonary exercise test. The patients' medical background, indexes obtained from lower-limb muscle strength and the cardiopulmonary exercise test, heart rate response indexes [Δ heart rate (ΔHR)], and autonomic nervous activities were measured, and these individual indexes were compared between the diabetic group and the non-diabetic group. Results: Compared with the non-diabetic group, the peak oxygen uptake (peak VO2) and ΔHR in the diabetic group were significantly lower (13.0 ± 2.2 vs. 14.9 ± 4.4 ml/kg/min and 27.2 ± 11.7 vs. 36.7 ± 14.7 bpm, respectively) (p