Improved Physical Performance and Decreased Muscular and Oxidative Damage With Postlunch Napping After Partial Sleep Deprivation in Athletes

Abstract

Purpose: To investigate the effects of napping after partial sleep deprivation (PSD) on reaction time, mood, and biochemical response to repeated-sprint exercise in athletes. Methods: Nine male judokas performed 4 test sessions in a counterbalanced and randomized order. Participants accomplished 1 control session after a normal sleep night (NSN) and 3 after PSD with (1) no nap, (2) ∼20-min nap (N20), and (3) ∼90-min nap (N90) opportunities. Test sessions included the running-based anaerobic sprint test, reaction time, Hooper index, and Epworth Sleepiness Scale. Muscle-damage biomarkers and antioxidant status were evaluated before and after exercise. Results: PSD decreased maximum (P < .001, d = 1.12), mean (P < .001, d = 1.33), and minimum (P < .001, d = 1.15) powers compared with NSN. However, N20 and N90 enhanced maximum power compared with PSD (P < .05, d = 0.54; P < .001, d = 1.06, respectively). Minimum power and mean power increased only after N90 (P < .001, d = 1.63; P < .001, d = 1.16, respectively). Epworth Sleepiness Scale increased after PSD (P < .001, d = 0.86) and decreased after N20 (P < .001, d = 1.36) and N90 (P < .001, d = 2.07). N20 reduced multiple-choice reaction time (P < .001, d = 0.61). Despite performance decrement, PSD increased postexercise aspartate aminotransferase (P < .001, d = 4.16) and decreased glutathione peroxidase (P < .001, d = 4.02) compared with NSN. However, the highest performances after N90 were accompanied with lesser aspartate aminotransferase (P < .001, d = 1.74) and higher glutathione peroxidase (P < .001, d = 0.86) compared with PSD. Conclusions: Napping could be preventive against performance degradation caused by sleep loss. A short nap opportunity could be more beneficial when the subsequent effort is brief and requires frequent decision making. However, a longer nap opportunity could be preventive against muscle and oxidative damage, even for higher performances.

A 90 min Daytime Nap Opportunity Is Better Than 40 min for Cognitive and Physical Performance

“…For example, following a normal night sleep, it has been shown that (i) a 25-min nap opportunity enhanced performance during the 5mSRT [12], (ii) a 25-min, 35-min and 45-min nap opportunity increased physical performance during the 5mSRT [13], (iii) a 35-min and 45-min nap opportunity enhanced 5 jump performance [11], and (iv) a 45-min [11] and 90-min [10] nap improved attention estimated by the digit cancelation test (DCT). After partial sleep deprivation, 30-min of napping improved sprint performance and alertness [14,16], and 20-min and 90-min of napping enhanced repeated sprint performance [15,17].…”

“…More than 1 h was allowed for participants to overcome any sleep inertia that might have occurred after napping. In fact, 30 min has been shown as sufficient to overcome sleep inertia [15][16][17].…”

“…After partial sleep deprivation, 30-min of napping improved sprint performance and alertness and decreased sleepiness [16] and 20-min and 90-min of napping enhanced repeated sprint performance [15,17]. While recommending athletes to add a nap during the day appears reasonable, there is little empirical evidence as to what nap duration is best for improving physical and cognitive performance.…”

“…While recommending athletes to add a nap during the day appears reasonable, there is little empirical evidence as to what nap duration is best for improving physical and cognitive performance. Hammouda et al [15] and Romdhani et al [17] reported that a 90-min nap increased repeated-sprint performance more than a 20-min nap in partially sleep-deprived athletes. After a normal night's sleep, Boukhris et al [13] demonstrated that a 45-min nap opportunity was the best duration, i.e., compared to a 25-min and a 35-min nap, for enhancing performance and reducing fatigue during the 5-m shuttle run test (5mSRT).…”

“…Additionally, a comparison between these two nap opportunities durations (i.e., 40-min vs. 90-min) was examined in the current study. These two durations (i.e., 40-min vs. 90-min) of nap opportunities were chosen in the present study because, based on previous studies, the longest nap duration was 90-min in the studies of Hammouda et al [15] and Romdhani et al [17]; whereas the longest ones in the study of Boukhris et al [13] and Hsouna et al [11] were only 45-min. We hypothesized that both nap durations would prove beneficial and a greater improvement in attention, physical performance, PRS, and reduction in sleepiness, DOMS, and RPE would be observed after a 90-min nap (N90), compared to a 40-min nap (N40) and no-nap (N0) condition.…”