title: Daily mood, shortness of breath, and lung function in asthma: concurrent and prospective associations.
abstract: OBJECTIVE
  Previous asthma diary studies have yielded equivocal findings on concurrent associations between lung function and mood, and prospective associations have rarely been explored. We therefore examined concurrent and prospective associations between daily mood, shortness of breath, and lung function, and studied between-individual variability and stability of concurrent associations across different times of the day.
  
  
  METHODS
  Twenty asthma patients and 20 healthy controls recorded their positive and negative mood, shortness of breath, physical activity, peak expiratory flow (PEF) and forced expiratory volume in the first second (FEV(1)) using an electronic pocket spirometer with diary functions three times per day for about 21 days.
  
  
  RESULTS
  For both groups, PEF showed positive concurrent associations with ratings of various mood states, whereas FEV(1) was only associated with positive mood. Both indices correlated negatively with shortness of breath. Within-individual concurrent associations varied significantly in both groups and their stability varied across time of the day, with overall higher stability for associations with shortness of breath in asthma and PEF for both groups. Prospectively, higher shortness of breath consistently predicted lower lung function later during the day and on the subsequent day.
  
  
  CONCLUSIONS
  The relationship between normal mood variations and lung function is highly variable across individuals and times of the day, limiting the predictive value of average group associations. Shortness of breath is predictive of future lung function decline in asthma. Future longitudinal research should focus on extreme emotional states, effort-independent measures of lung function, and additional indicators of asthma control.
authors.affiliation: Department of Psychology, Southern Methodist University, Dallas, TX 75205, USA. tritz@smu.edu
authors.forename: Thomas
authors.initials: T
authors.lastname: Ritz
authors.forename: David
authors.initials: D
authors.lastname: Rosenfield
authors.forename: Steve
authors.initials: S
authors.lastname: Dewilde
authors.forename: Andrew
authors.initials: A
authors.lastname: Steptoe
mesh_terms: D000328:Adult; D000339:Affect; D001249:Asthma / Q000503:physiopathology* / Q000523:psychology*; D004417:Dyspnea / Q000503:physiopathology* / Q000523:psychology*; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D010366:Peak Expiratory Flow Rate; D012044:Regression Analysis