ORIGINAL ARTICLE Respiratory muscle impairment in dialysis patients: can minimal dose of exercise limit the damage? A Preliminary study in a sample of patients enrolled in the EXCITE trial Luca Pomidori 1,7 • Nicola Lamberti 2 • Anna Maria Malagoni 1,8 • Fabio Manfredini 2 • Enrico Pozzato 1,7 • Michele Felisatti 1,7 • Luigi Catizone 3 • Antonio Barilla ` 3 • Alessandro Zuccala ` 4 • Giovanni Tripepi 5 • Francesca Mallamaci 5,6 • Carmine Zoccali 6 • Annalisa Cogo 1,2 Received: 22 March 2016 / Accepted: 5 June 2016 Ó Italian Society of Nephrology 2016 Abstract Aim Skeletal muscle atrophy and dysfunction with asso- ciated weakness may involve the respiratory muscles of dialysis patients. We evaluated the effect of moderate-in- tensity exercise on lung function and respiratory muscle strength. Methods Fifty-nine patients (25 F, aged 65 ± 13 years) from two centers participating in the multicenter random- ized clinical trial EXerCise Introduction To Enhance Per- formance in Dialysis (EXCITE) were studied. Subjects were randomized into a prescribed exercise group (E), wherein subjects performed two 10-min walking sessions every second day at an intensity below the self-selected speed, or a control group (C) with usual care. Physical performance was assessed by the 6-min walk test (6MWT). Patient lung function and respiratory muscle strength were evaluated by spirometry and maximal inspiratory pressure (MIP), respectively. Results Forty-two patients (14 F) completed the study. At baseline, the groups did not differ in any parameters. In total, 7 patients (4 in E; 3 in C) showed an obstructive pattern. The pulmonary function parameters were signifi- cantly correlated with 6MWT but not with any biochemical measurements. Group E safely performed the exercise program. At follow-up, the spirometry parameters did not change in either group. A deterioration of MIP (-7 %; p = 0.008) was observed in group C, but not in group E (?3.3 %, p = ns). In E, an increase of 6MWT was also found (?12 vs. 0 % in C; p = 0.038). Conclusion In dialysis patients, a minimal dose of struc- tured exercise improved physical capacity and maintained a stable respiratory muscle function, in contrast to the control group where it worsened. Keywords Chronic kidney disease Á Dialysis Á Exercise Á Respiratory function tests Á Muscle weakness Introduction Atrophy and increased non-contractile tissue are features of the muscles of patients on hemodialysis (HD), and they are associated with poor physical performance [1]. A number of factors, including malnutrition, uremic toxins, acidosis, vitamin D deficiency, altered potassium meta- bolism, insulin resistance and hypercalcemia, are responsible for structural muscle changes and inefficient contractility [2–4]. These factors combine with the & Luca Pomidori pmdlcu@unife.it 1 Biomedical Sport Studies Centre, University of Ferrara, Ferrara, Italy 2 Department of Biomedical and Surgical Specialties Sciences, Section of Sport Sciences, University of Ferrara, Ferrara, Italy 3 Nephrology Dialysis Unit, Hospital University of Ferrara, Ferrara, Italy 4 Nephrology Dialysis Unit, Civil Hospital of Imola, Imola, Italy 5 CNR-IFC, Clinical Epidemiology and Physiopathology of Renal Diseases and Hypertension of Reggio Calabria, Reggio Calabria, Italy 6 Nephrology and Renal Transplantation Division, Ospedali Riuniti, Reggio Calabria, Italy 7 Present Address: Esercizio Vita ONLUS, Via Don Giovanni Calabria 13, 44124 Ferrara, Italy 8 Present Address: Unit of Translational Surgery, Hospital University of Ferrara, Ferrara, Italy 123 J Nephrol DOI 10.1007/s40620-016-0325-2