Impact of diabetes mellitus on functional exercise capacity and pulmonary functions in patients with diabetes and healthy persons

BACKGROUND: Chronic diabetic complications may afflict all organ tissues, including those of the respiratory system. The six-minute walk test (6MWT) is an alternative and widely used method of assessing functional capacity and is simple to perform. However, to our knowledge, the impact of diabetes mellitus on 6MWT performance has not been investigated previously. This research aimed to compare the functional exercise capacity and pulmonary functions in patients with diabetes and in healthy persons. METHODS: The study included 131 participants: 64 patients with type 1 and 2 diabetes mellitus (DM) and 67 healthy participants (CG). All of the participants were nonsmoking and did not have pulmonary disorders that affected the pulmonary function tests or 6MWT. Metabolic parameters and biochemical markers of inflammation were assessed. Full lung function tests and a 6MWT were performed. RESULTS: In the DM group, the walking distance was 109 m shorter than that in the CG (P < 0.001). Moreover, compared to the CG, the DM group showed lower values of forced expiratory volume in one second (FEV1 (l) 3.6 vs. 2.8, P < 0.001) and total lung capacity (TLC (l) 6.6 vs. 5.6, P < 0.001), as well as a decrease in diffusion capacity (DLCO (mmol/min/kPa), 10.0 vs. 8.6, P < 0.001). CONCLUSIONS: The 6MWT is a valuable test that complements the assessment of daily physical capacity in patients with diabetes, irrespective of type. Pulmonary function and the capacity for physical exertion varied between patients with diabetes mellitus and the healthy participants in the CG.