title: Hypocapnia and its relation to fear of falling.
abstract: OBJECTIVE
  To determine if hypocapnia occurs in patients with fear of falling and to explore potential causes of hypocapnia.
  
  
  METHODS
  Observational study in patients who fall with and without fear of falling.
  
  
  METHODS
  Rehabilitation wards of an elderly care unit.
  
  
  METHODS
  Consecutive fallers with (n = 20) and without (n = 10) fear of falling.
  
  
  METHODS
  End-tidal CO2 (PETCO2) and respiratory rate (RR) responses were measured during sustained isometric muscle contraction (SIMC) (40% of maximum voluntary contraction of quadriceps for 2 min) and during a 5-meter walk. Falls efficacy scale (FES) and Hospital anxiety and depression scale (HAD).
  
  
  RESULTS
  Patients with fear of falling had significantly higher FES and HAD scores (p < .01). During SIMC, baseline and nadir PETCO2 levels were significantly lower in patients with a fear of falling (p < .01). During the 5-meter walk, PETCO2 was lower at baseline, at nadir, and at the end of the walk in the fear of falling group than in controls (p < .01). RR was higher at nadir and end of the walk in the fear of falling group than in controls (p < .02).
  
  
  CONCLUSIONS
  Hypocapnia may occur in patients with a fear of falling during SIMC and walking. Anxiety seems to be the main cause, but muscle weakness may contribute. Breathing or relaxation techniques and reconditioning may have a role in treating fear of falling in the rehabilitation setting.
authors.affiliation: Geriatric Medicine, Clinical Division 1, University of Manchester, UK.
authors.forename: J E
authors.initials: JE
authors.lastname: Clague
authors.forename: P J
authors.initials: PJ
authors.lastname: Petrie
authors.forename: M A
authors.initials: MA
authors.lastname: Horan
mesh_terms: D000058:Accidental Falls; D000368:Aged; D000369:Aged, 80 and over; D001007:Anxiety / Q000150:complications* / Q000175:diagnosis / Q000523:psychology; D005239:Fear / Q000523:psychology*; D005260:Female; D006801:Humans; D016857:Hypocapnia / Q000175:diagnosis* / Q000209:etiology* / Q000523:psychology; D007537:Isometric Contraction; D008297:Male; D011659:Pulmonary Gas Exchange; D012119:Respiration; D016138:Walking