In a real-life setting, the loss of approximately 6% body mass within 5 days induced hypohydration, which became evident by the decreases in body water and plasma volume. The reduction in tHbmass was a surprising observation that needs further investigation.
The aim of the study was to test the hypothesis that iron supplementation in well-trained non-iron-depleted athletes leads to an enhanced increase of total body hemoglobin (TBH) during training at moderate altitude. Therefore, the members of the national German boxing team were randomly assigned to treatment with ferrous-glycine-sulfate (1335 mg equivalent to 200mg elementary iron daily) or with placebo during 18 days of endurance training at moderate altitude (1800 m). Before and after altitude training TBH was determined by CO-rebreathing, measures of exercise performance were determined with an incremental treadmill test. Before, during and after the stay at moderate altitude erythropoietin (Epo), reticulocytes (Retics) and parameters of iron metabolism were measured in venous blood. The results show that TBH did not change significantly in the placebo-group and even slightly, but significantly decreased in the iron-treated group. However, there was a significant increase of Epo and Retics in both groups during training at moderate altitude whereas parameters of iron metabolism remained unchanged. VO2max did not change either. To test whether a training-induced hemolysis, an increased urinary iron excretion or gastrointestinal blood loss could explain the unexpected drop of TBH we tested most of the boxers again during a similar training camp at low altitude (400-1000 m) to obtain measures of hemolysis, urinary iron excretion and occult hemoglobin loss with the stools. Although there were signs of an increased erythrocyte turnover no iron loss could be observed. We conclude that 18 days of endurance training at an altitude of 1800 m does not lead to an increase of TBH in non-iron-depleted athletes with and without iron supplementation.
The data demonstrated that prolonged exercise is necessary for exercise-induced activation of coagulation resulting in thrombin and fibrin formation and suggested that endothelial cell activation possibly due to mechanical factors associated with running might play a role.
Dietary intake, vitamin status and oxidative stress were evaluated in 17 elite male boxers. Ten of them frequently reduced body weight rapidly before competitions (Weight Loss Group) and 7 did not practice rapid weight loss (Control Group). Food record checklists, blood samples for determination of vitamin status and plasma glutathione levels were obtained during a week of weight maintenance, a pre-competition week and a post-competition week. The average dietary intakes in both groups were 33 ± 8 kcal·kg(-1), 3.7 ± 1.1 g·kg(-1) carbohydrates, 1.5 ± 0.4 g·kg(-1) protein, 1.2 ± 0.4 g·kg(-1) fat and 2.2 ± 1.0 L water per day (excluding pre-competition week in Weight Loss Group). Energy (18 ± 7 kcal·kg(-1)), carbohydrate (2.2 ± 0.8 g·kg(-1)), protein (0.8 ± 0.4 g·kg(-1)), fat (0.6 ± 0.3 g·kg(-1)) and water (1.6 ± 0.6 L) consumption (P-values <0.001) and intakes of most vitamins (P-values < 0.05) were significantly reduced during the pre-competition week in the Weight Loss Group. In both groups, the intakes of vitamins A, E and folate were below recommended values throughout the three periods; however, blood vitamin and plasma glutathione levels did not change significantly. Our findings indicate a low-caloric and low-carbohydrate diet in elite boxers, regardless of participating in rapid weight loss or not. Apparently, the pre-competitional malnutitrition in the Weight Loss Group did not induce alterations in the vitamin and glutathione status.
BACKGROUND AND PURPOSE:The evidence for traumatic brain injury in amateur boxers is controversial. Hypothetically, sudden acceleration of the head due to the impact of the blow during the boxing fight might result in diffuse axonal injury or contusion. We wanted to determine whether cerebral microhemorrhages occur more often in amateur boxers than in nonboxers.
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