Does Ramadan fasting affect the diurnal variations in metabolic responses and total antioxidant capacity during exercise in young soccer players?

Abstract

The aim of this study was to investigate the effects of Ramadan fasting and time-of-day on biochemical responses to an intermittent exercise [Yo–Yo test level 1, (YYIRT)]. Twenty male soccer players (17.52 ± 0.2 years, 177.4 ± 2.9 cm) completed the YYIRT at 0700 and 1700 hours on three occasions: 1 week before Ramadan (BR), the second week of Ramadan (SWRR2), and the fourth week of Ramadan (ERR4). The total distance covered during the YYIRT (TD) was recorded. Moreover, blood samples were obtained before and after the YYIRT for biochemical measurements. TD was higher BR than during Ramadan in the evening (P < 0.05), but not in the morning. However, there was no significant difference between BR and Ramadan in the morning. While post-exercise values of blood lactate (Lac), glucose (GLC), and markers of muscle injury were greater higher in the evening, resting total antioxidant status (TAS) and uric acid (UA) levels were higher in the morning as compared with the evening BR. These diurnal variations were hidden during Ramadan due to a significant decrease in Lac (P < 0.01), GLC (P < 0.05) and cellular damage (P < 0.05) and an increase in TAS and UA (P < 0.05) values in the evening. No significant difference in biochemical responses was observed in the morning during SWRR2 and ERR4 as compared with BR. In summary, the present study indicates that YYIRT performance was affected by Ramadan fasting only in the evening in young soccer players. The modified diurnal pattern of biochemical responses could explain this performance decrement.