title: Medicinal clays improve the endurance of loaded inspiratory muscles in COPD: a randomized clinical trial of nonpharmacological treatment.
abstract: BACKGROUND
  Inspiratory resistive breathing (IRB) challenges affect respiratory muscle endurance in healthy individuals, which is considered to be an interleukin 6 (IL-6)-dependent mechanism. Whether nonpharmacological thermal therapies promote the endurance of loaded inspiratory muscles in chronic obstructive pulmonary disease (COPD) is unclear. The objectives of this study were to compare the effects of two thermal interventions on endurance time (ET) and plasma IL-6 concentration following an IRB challenge.
  
  
  METHODS
  This study was a randomized, parallel-group, unblinded clinical trial in a single-center setting. Forty-two patients (aged 42-76 years) suffering from mild to severe COPD participated in this study. Both groups completed 12 sessions of the mud bath therapy (MBT) (n=22) or leisure thermal activity (LTA) (n=19) in a thermal spa center in Italy. Pre- and postintervention spirometry, maximum inspiratory pressure, and plasma mediators were obtained and ET and endurance oxygen expenditure (VO2Endur) were measured following IRB challenge at 40% of maximum inspiratory pressure.
  
  
  RESULTS
  There was no difference in ΔIL-6 between the intervention groups. But, IRB challenge increased cytokine IL-6 plasma levels systematically. The effect size was small. A statistically significant treatment by IRB challenge effect existed in ET, which significantly increased in the MBT group (P=0.003). In analysis of covariance treatment by IRB challenge analysis with LnVO2Endur as the dependent variable, ΔIL-6 after intervention predicted LnVO2Endur in the MBT group, but not in the LTA group. Adverse events occurred in two individuals in the MBT group, but they were mainly transient. One patient in the LTA group dropped out.
  
  
  CONCLUSIONS
  MBT model improves ET upon a moderate IRB challenge, indicating the occurrence of a training effect. The LnVO2Endur/ΔIL-6 suggests a physiologic adaptive mechanism in respiratory muscles of COPD patients allocated to treatment. Both thermal interventions are safe.
authors.affiliation: Department of Pneumology, Scientific Institute of Montescano, Salvatore Maugeri Foundation, Istituto Di Ricovero e Cura a Carattere Scientifico, Montescano (Pavia).
authors.forename: Simonetta
authors.initials: S
authors.lastname: Baldi
authors.affiliation: Department of Biomedical Engineering, Scientific Institute of Montescano, Salvatore Maugeri Foundation, Istituto Di Ricovero e Cura a Carattere Scientifico, Montescano (Pavia), AbanoTerme, Padua, Italy.
authors.forename: Gian Domenico
authors.initials: GD
authors.lastname: Pinna
authors.affiliation: Department of Pneumology, Scientific Institute of Montescano, Salvatore Maugeri Foundation, Istituto Di Ricovero e Cura a Carattere Scientifico, Montescano (Pavia).
authors.forename: Claudio
authors.initials: C
authors.lastname: Bruschi
authors.affiliation: Center of Thermal Studies Pietro d'Abano, AbanoTerme, Padua, Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Caldara
authors.affiliation: Department of Biomedical Engineering, Scientific Institute of Montescano, Salvatore Maugeri Foundation, Istituto Di Ricovero e Cura a Carattere Scientifico, Montescano (Pavia), AbanoTerme, Padua, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Maestri
authors.affiliation: Department of Pneumology, Scientific Institute of Montescano, Salvatore Maugeri Foundation, Istituto Di Ricovero e Cura a Carattere Scientifico, Montescano (Pavia).
authors.forename: Elena
authors.initials: E
authors.lastname: Dacosto
authors.affiliation: Department of Pneumology, Scientific Institute of Montescano, Salvatore Maugeri Foundation, Istituto Di Ricovero e Cura a Carattere Scientifico, Montescano (Pavia).
authors.forename: Antonella
authors.initials: A
authors.lastname: Rezzani
authors.affiliation: Department of Pneumology, Scientific Institute of Montescano, Salvatore Maugeri Foundation, Istituto Di Ricovero e Cura a Carattere Scientifico, Montescano (Pavia).
authors.forename: Ermanno
authors.initials: E
authors.lastname: Popovich
authors.affiliation: Department of Pneumology, Scientific Institute of Montescano, Salvatore Maugeri Foundation, Istituto Di Ricovero e Cura a Carattere Scientifico, Montescano (Pavia).
authors.forename: Ezio
authors.initials: E
authors.lastname: Bellinzona
authors.affiliation: Department of Pneumology, Scientific Institute of Montescano, Salvatore Maugeri Foundation, Istituto Di Ricovero e Cura a Carattere Scientifico, Montescano (Pavia).
authors.forename: Paola
authors.initials: P
authors.lastname: Crotti
authors.affiliation: Department of Pneumology, Scientific Institute of Montescano, Salvatore Maugeri Foundation, Istituto Di Ricovero e Cura a Carattere Scientifico, Montescano (Pavia).
authors.forename: Silvia
authors.initials: S
authors.lastname: Montemartini
authors.affiliation: Department of Pneumology, Scientific Institute of Montescano, Salvatore Maugeri Foundation, Istituto Di Ricovero e Cura a Carattere Scientifico, Montescano (Pavia).
authors.forename: Claudio
authors.initials: C
authors.lastname: Fracchia
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D005260:Female; D006801:Humans; D001239:Inhalation; D015850:Interleukin-6 / Q000097:blood; D007558:Italy; D008297:Male; D008875:Middle Aged; D009094:Mud Therapy; D053580:Muscle Strength; D010807:Physical Endurance; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood / Q000175:diagnosis / Q000503:physiopathology / Q000534:rehabilitation*; D020127:Recovery of Function; D012132:Respiratory Muscles / Q000503:physiopathology*; D012720:Severity of Illness Index; D013147:Spirometry; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; C508600:IL6 protein, human; D015850:Interleukin-6
keywords: balneotherapy; cytokine IL-6; hydrotherapy; inspiratory resistive breathing; pulmonary rehabilitation