Conducting an Acute Intense Interval Exercise Session During the Ramadan Fasting Month: What Is the Optimal Time of the Day?

Abstract

This study examines the effects of Ramadan fasting on performance during an intense exercise session performed at three different times of the day, i.e., 08:00, 18:00, and 21:00 h. The purpose was to determine the optimal time of the day to perform an acute high-intensity interval exercise during the Ramadan fasting month. After familiarization, nine trained athletes performed six 30-s Wingate anaerobic test (WAnT) cycle bouts followed by a time-to-exhaustion (T_exh) cycle on six separate randomized and counterbalanced occasions. The three time-of-day nonfasting (control, CON) exercise sessions were performed before the Ramadan month, and the three corresponding time-of-day Ramadan fasting (RAM) exercise sessions were performed during the Ramadan month. Note that the 21:00 h session during Ramadan month was conducted in the nonfasted state after the breaking of the day's fast. Total work (TW) completed during the six WAnT bouts was significantly lower during RAM compared to CON for the 08:00 and 18:00 h (p < .017; effect size [d] = .55 [small] and .39 [small], respectively) sessions, but not for the 21:00 h (p = .03, d = .18 [trivial]) session. The T_exh cycle duration was significantly shorter during RAM than CON in the 18:00 (p < .017, d = .93 [moderate]) session, but not in the 08:00 (p = .03, d = .57 [small]) and 21:00 h (p = .96, d = .02 [trivial]) sessions. In conclusion, Ramadan fasting had a small to moderate, negative impact on quality of performance during an acute high-intensity exercise session, particularly during the period of the daytime fast. The optimal time to conduct an acute high-intensity exercise session during the Ramadan fasting month is in the evening, after the breaking of the day's fast. (Author correspondence: [email protected])

Keywords:

• Aerobic
• Anaerobic
• Circadian rhythm
• Exercise
• Ramadan fasting
• Time-of-day
• Time-to-exhaustion
• Wingate test

ACKNOWLEDGMENTS

The authors gratefully acknowledge the participation and cooperation of the athletes and coaches of the Singapore Silat Federation. Part of this study was presented at the 1st International Consensus Meeting on Ramadan and Football, at Aspetar in Doha, Qatar, 25–26 November 2011.

Declaration of Interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.