title: Changes in blood values in elite cyclist.
abstract: In 2006, a couple of professional cycling teams initiated their own testing programs. The objective of this study is to describe fluctuations in commonly measured blood parameters among top-level riders. From December 12th 2006 to November 30th 2007, a total of 374 blood samples and 287 urine samples were obtained from 28 elite, male cyclists. Blood was analyzed for hematocrit (Hct), hemoglobin concentration ([Hb]) and % reticulocytes. Seventy-six percent of all samples were collected out-of-competition (OOC). From December 2006 to September 2007, the average Hct and [Hb] decreased by 4.3 percent point and 1.3 g/dL, respectively. After the end of the competitive season, the values increased back to baseline levels. During the Tour de France, the [Hb] decreased by 11.5 %, with individual decreases ranging from 7.0 to 20.6 %. Hct and [Hb] values were lower in-competition (40.9 % and 14.1 g/dL) compared to OOC (43.2 % and 15.0 g/dL) and pre-competition (43.5 % and 14.9 g/dL). Our results suggest that when interpreting blood sample results in an anti-doping context, the sample timing (OOC, pre- or in-competition) and time of year should be kept in mind.
authors.affiliation: Anesthesiology, Bispebjerg Hospital, Copenhagen NV, Denmark. jakobmoerkeberg@hotmail.com
authors.forename: J S
authors.initials: JS
authors.lastname: Mørkeberg
authors.forename: B
authors.initials: B
authors.lastname: Belhage
authors.forename: R
authors.initials: R
authors.lastname: Damsgaard
mesh_terms: D000328:Adult; D001642:Bicycling / Q000502:physiology*; D003163:Competitive Behavior; D004300:Doping in Sports; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D006400:Hematocrit; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D008297:Male; D012156:Reticulocytes; D055815:Young Adult
chemical_list: D006454:Hemoglobins