title: Seasonal variations of haematological parameters in athletes.
abstract: The influence of training and competition workloads is crucial for evaluation of longitudinal haematological data in athletes. There are only a few papers on the variation of haematological parameters during long-lasting periods and, especially, during an entire competitive season. We summarized that some haematological parameters can be influenced by long-term training and competition periods. Haemoglobin (Hb) and haematocrit (Ht) are decreased during the more intense periods of training, throughout the season. In different sport disciplines, the decline of Hb ranges from 3 to 8% during the competition season, while the range of reticulocytes (Ret%) varies from 5 to 21%. Reticulocytes are also decreased after long periods of training and competitions, but their variation is not necessarily associated with that of Hb. The qualitative variations (trend of modifications) of haematological parameters are roughly independent of the sport discipline, but quantitatively (amount of modifications) dependent on sport discipline. The modifications are more evident in cycling, running, swimming than they are in football and rugby. The variations of haematological parameters within the same sport discipline are qualitatively concordant and quantitatively different among separate but consecutive competitive seasons. These findings are described in aerobic and team sports sportsmen. The definition of reliable reference ranges in sportsmen would only be possible by following the best laboratory practices. For antidoping purposes more studies investigating haematological modifications during the season are advisable.
authors.affiliation: IRCCS Galeazzi and School of Medicine, University of Milan, Milan, Italy. giuseppe.banfi1@unimi.it
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Banfi
authors.forename: Carsten
authors.initials: C
authors.lastname: Lundby
authors.forename: Paul
authors.initials: P
authors.lastname: Robach
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Lippi
mesh_terms: D056352:Athletes; D006400:Hematocrit; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D017701:Reticulocyte Count; D012156:Reticulocytes / Q000378:metabolism*; D012420:Running / Q000502:physiology; D012621:Seasons; D013177:Sports / Q000502:physiology*
chemical_list: D006454:Hemoglobins