Variations in oxidative stress markers in elite basketball players at the beginning and end of a season

Abstract

The aim of the present study was to examine the changes occuring in the redox status in male basketball players at the beginning and end of a highly competitive season. For this purpose, the redox status of 14 professional athletes of a European basketball club was examined at 2 different time points, at the beginning (phase 1) and at the end of the season (phase 2). The redox status was assessed in blood using conventional oxidative stress markers, such as thiobarbituric acid reactive substances (TBARS), protein carbonyls (CARB) and the total antioxidant capacity (TAC) in plasma, as well as glutathione (GSH) levels and catalase (CAT) activity in erythrocytes. Moreover, a new static oxidation-reduction potential marker (sORP) was assessed in plasma. Our results revealed that sORP was significantly increased by 9.6% and GSH levels were significantly decreased by 35.0% at phase 2 compared to phase 1, indicating the induction of oxidative stress due to excessive exercise. Moreover, TAC was significantly increased by 12.9% at phase 2 compared to phase 1, indicating the activation of adaptive responses for counteracting oxidative stress. The CARB and TBARS levels were not significantly altered between the 2 phases, although there was a significant correlation (r=0.798) between the sORP and CARB levels. Furthermore, the variations in these markers between athletes were examined. We found that 3 markers exhibited a similar response between athletes, that is, sORP was increased in all 14 athletes, TAC was increased in 13 and the GSH levels were decreased in 14. However, the other 3 markers (i.e., TBARS, CARB and CAT) exhibited marked variations between the athletes, suggesting that the optimal approach with which to counteract (e.g., antioxidant supplementation) the observed increase in oxidative stress is the individualized examination of the redox status of athletes using a series of markers. This would allow the identification of athletes affected by severe oxidative stress and inflammation, and would thus indicate when necessary intervention measures are required to improve their health and performance.

Keywords: basketball; glutathione; oxidation-reduction potential; oxidative stress.

Figure 1.

Values (means ± standard error of the mean) of the oxidative stress marker, static oxidation-reduction potential (sORP), in the plasma of basketball players at the beginning (phase 1) and end of season (phase 2). *P<0.05, significantly different compared with phase 1.

Figure 2.

Values (means ± standard error of the mean) of oxidative stress markers in plasma of basketball players at the beginning (phase 1) and end of season (phase 2). (A) Protein carbonyl (CARB) levels, (B) thiobarbituric acid reactive substances (TBARS) levels, (C) total antioxidant capacity (TAC). *P<0.05, significantly different compared with phase 1.

Figure 3.

Values (means ± standard error of the mean) of oxidative stress markers in erythrocytes of basketball players at the beginning (phase 1) and end of season (phase 2). (A) Glutathione (GSH) levels, (B) catalase (CAT) activity. *P<0.05, significantly different compared with phase 1.

Figure 4.

Percentage changes in oxidative stress biomarkers of each individual at the end of season (phase 2) compared to the beginning of season (phase 1). (A) Static oxidation-reduction potential (sORP) (in plasma), (B) total antioxidant capacity (TAC) (in plasma), (C) protein carbonyl (CARB) (in plasma), (D) thiobarbituric acid reactive substances (TBARS) (in plasma), (E) glutathione (GSH) (in erythrocytes) and (F) catalase (CAT) activity (in erythrocytes). Each bar represents the percentage difference in the level of each marker between phase 2 and phase 1.

Figure 5.

Correlation of percentage change [i.e., change between the beginning (phase 1) and end of season (phase 2)] between static oxidation-reduction potential (sORP) and protein carbonyl (CARB).