title: Mouth breathing and forward head posture: effects on respiratory biomechanics and exercise capacity in children.
abstract: OBJECTIVE
  To evaluate submaximal exercise tolerance and respiratory muscle strength in relation to forward head posture (FHP) and respiratory mode in children, comparing mouth-breathing (MB) children with nasal-breathing (NB) children.
  
  
  METHODS
  This was a controlled, analytical cross-sectional study involving children in the 8-12 year age bracket with a clinical otorhinolaryngology diagnosis of MB, recruited between October of 2010 and January of 2011 from the Mouth Breather Clinic at the State University of Campinas Hospital de Clínicas, located in the city of Campinas, Brazil. The exclusion criteria were obesity, asthma, chronic respiratory diseases, heart disease, and neurological or orthopedic disorders. All of the participants underwent postural assessment and the six-minute walk test (6MWT), together with determination of MIP and MEP.
  
  
  RESULTS
  Of the 92 children in the study, 30 presented with MB and 62 presented with NB. In the MB group, the differences between those with moderate or severe FHP and those with normal head posture, in terms of the mean MIP, MEP and six-minute walk distance (6MWD), were not significant (p = 0.079, p = 0.622, and p = 0.957, respectively). In the NB group, the mean values of MIP and MEP were higher in the children with moderate FHP than in those with normal head posture (p = 0.003 and p = 0.004, respectively). The mean MIP, MEP, and 6MWD were lower in the MB group than in the NB group. Values of MIP and MEP were highest in the children with moderate FHP.
  
  
  CONCLUSIONS
  Respiratory biomechanics and exercise capacity were negatively affected by MB. The presence of moderate FHP acted as a compensatory mechanism in order to improve respiratory muscle function.
authors: State University at Campinas – Campinas, Brazil. re_okuro@yahoo.com.br
authors: Renata Tiemi
authors: RT
authors: Okuro
authors: André Moreno
authors: AM
authors: Morcillo
authors: Maria Ângela Gonçalves Oliveira
authors: MÂ
authors: Ribeiro
authors: Eulália
authors: E
authors: Sakano
authors: Patrícia Blau Margosian
authors: PB
authors: Conti
authors: José Dirceu
authors: JD
authors: Ribeiro
mesh_terms: D001945:Breathing Exercises; D016022:Case-Control Studies; D002648:Child; D003430:Cross-Sectional Studies; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D006257:Head; D006801:Humans; D008297:Male; D009058:Mouth Breathing / Q000503:physiopathology*; D011187:Posture / Q000502:physiology*; D012129:Respiratory Function Tests; D015656:Respiratory Mechanics / Q000502:physiology*; D012132:Respiratory Muscles / Q000503:physiopathology; D012720:Severity of Illness Index