title: Predicting sickness during a 2-week soccer camp at 3600 m (ISA3600).
abstract: OBJECTIVE
  To examine the time course of changes in wellness and health status markers before and after episodes of sickness in young soccer players during a high-altitude training camp (La Paz, 3600 m).
  
  
  METHODS
  Wellness and fatigue were assessed daily on awakening using specifically-designed questionnaires and resting measures of heart rate and heart rate variability. The rating of perceived exertion and heart rate responses to a submaximal run (9 km/h) were also collected during each training session. Players who missed the morning screening for at least two consecutive days were considered as sick.
  
  
  RESULTS
  Four players met the inclusion criteria. With the exception of submaximal exercise heart rate, which showed an almost certain and large increase before the day of sickness (4%; 90% confidence interval 3 to 6), there was no clear change in any of the other psychometric or physiological variables. There was a very likely moderate increase (79%, 22 to 64) in self-reported training load the day before the heart rate increase in sick players (4 of the 4 players, 100%). In contrast, training load was likely and slightly decreased (-24%, -78 to -11) in players who also showed an increased heart rate but remained healthy.
  
  
  CONCLUSIONS
  A >4% increased heart rate during submaximal exercise in response to a moderate increase in perceived training load the previous day may be an indicator of sickness the next day. All other variables, that is, resting heart rate, heart rate variability and psychometric questionnaires may be less powerful at predicting sickness.
authors.affiliation: ASPIRE Academy for Sports Excellence, , Doha, Qatar.
authors.forename: Martin
authors.initials: M
authors.lastname: Buchheit
authors.forename: Ben M
authors.initials: BM
authors.lastname: Simpson
authors.forename: Walter F
authors.initials: WF
authors.lastname: Schmidt
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Aughey
authors.forename: Rudy
authors.initials: R
authors.lastname: Soria
authors.forename: Robert A
authors.initials: RA
authors.lastname: Hunt
authors.forename: Laura A
authors.initials: LA
authors.lastname: Garvican-Lewis
authors.forename: David B
authors.initials: DB
authors.lastname: Pyne
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Gore
authors.forename: Pitre C
authors.initials: PC
authors.lastname: Bourdon
mesh_terms: D000208:Acute Disease / Q000628:therapy*; D000293:Adolescent; D000531:Altitude; D001315:Australia / Q000208:ethnology; D001838:Bolivia / Q000208:ethnology; D042241:Early Diagnosis; D015444:Exercise / Q000502:physiology; D005221:Fatigue / Q000175:diagnosis / Q000208:ethnology; D006304:Health Status; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D011594:Psychometrics; D012916:Soccer / Q000502:physiology*
keywords: Altitude; Cardiology prevention; Fatigue; Physiology; Soccer