title: Biorhythm theory does not predict admission for acute myocardial infarction.
abstract: OBJECTIVE
  Temporal variations in the incidence of acute myocardial infarction (AMI) have been described. However, AMI occurrence and biorhythm theory, which proposes the existence of three endogenous independent infradian cycles and AMI occurrence, has not been well studied. The purpose of this study is to determine whether specific days in the biorhythm cycles are related to AMI incidence.
  
  
  METHODS
  Patients (40-85 years old) admitted for AMI at the Sherbrooke University Hospital Center, 1993-2008 were subjects of this study. Potential vulnerable days and performance days of the biorhythm cycles were calculated using birth and admission dates from the warehouse database. Observed AMI frequencies were compared to those expected using χ² tests.
  
  
  RESULTS
  There were 11,395 admissions for AMI. No relation was noted between single, double, or triple critical or noncritical days and AMI (χ² = 3.78; p > 0.05). Observed and expected AMI frequencies for maximal and minimal performance days were similar (χ² = 15.06; p > 0.05).
  
  
  CONCLUSIONS
  We found no evidence for a possible relationship between the date of AMI and critical maximum and minimum performance days of an individual's physical, emotional, or intellectual biorhythm cycles. We conclude that biorhythm theory does not predict admission for AMI.
authors.affiliation: Department of Medicine, University of Sherbrooke, Sherbrooke, Quebec, Canada.
authors.forename: Sébastien X
authors.initials: SX
authors.lastname: Joncas
authors.forename: Nathalie
authors.initials: N
authors.lastname: Carrier
authors.forename: Michel
authors.initials: M
authors.lastname: Nguyen
authors.forename: Paul
authors.initials: P
authors.lastname: Farand
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006760:Hospitalization; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D009203:Myocardial Infarction / Q000503:physiopathology*; D010507:Periodicity