We aimed to investigate the effects of a 25-min nap opportunity on physical performance during the 5-m shuttle run test (5mSRT), feelings (i.e., evaluated by the feeling scale), attention (i.e., evaluated by the digit cancellation test) and the perception of fatigue (i.e., recorded by the rating of perceived exertion (RPE)) during Ramadan observance. Twelve physically active men (age: 21.1 ± 3.2 yrs, height: 1.76 ± 0.05 m, body-mass: 71.2 ± 9.3 kg) voluntarily participated in five test sessions: 15 days before Ramadan (BR), the first 10 days of Ramadan (FR), the last 10 days of Ramadan (ER), 10 days after Ramadan (10AR) and 20 days after Ramadan (20AR). During each test session, participants performed the digit cancellation test, a 5-min standard warm-up, the 5mSRT (6 × 30-s with 35-s intervals-between) and the rating of perceived exertion (RPE) after no-nap (N0) and 25-min nap opportunity (N25) conditions. Participants also completed the Pittsburgh Sleep Quality Index (PSQI) during each period. The total distance covered during the 5mSRT did not differ significantly before, during or after Ramadan, but was significantly greater after N25 compared to N0 at 10AR (687.5 ± 23.0 m vs. 725.6 ± 41.1 m; p = 0.018) and 20AR (698.3 ± 19.8 m vs. 742.6 ± 58.3 m; p = 0.003). The attention scores were higher after N25 in comparison with N0 at 10AR (p = 0.04) and 20AR (p = 0.02). RPE scores were not significantly different between N25 and N0 conditions. Feelings scores were higher after N25 compared to N0 during both FR (p = 0.007) and 20AR (p = 0.04). A significant deterioration of sleep quality was recorded during Ramadan (i.e., PSQI scores were significantly higher during and after compared to BR (p < 0.0005)). A 25-min nap opportunity was beneficial for physical and cognitive performance after Ramadan observance; however, any effect is insufficient to show significant beneficial impacts during Ramadan.
Keywords: exercise; fasting; fatigue; nap; sleep.