The scientists had previously examined the iron metabolism in 20 elite rowing athletes and 10 professional soccer players at the end of a competitive season, after recuperation and during pre-season training and found:
At the end of season, 27% of all athletes had absolute ID [iron deficiency] and 70% showed functional ID. Absolute iron depletion was not generally restored after recuperation and observed at all time points in 14% of the athletes. Although athletes with initially low ferritin levels showed a slight increase during recuperation (p < 0.09), these increases remained within borderline levels. Furthermore, 10% showed borderline haemoglobin levels, suggestive of mild anaemia, as defined by the World Health Organisation.While I would not suggest supplementing with iron without due reason, this study should remind you to have your levels checked, at least once a year in order to intervene before you actually feel the negative effects of low iron and anemia.