“Post-lunch sleepiness belongs to biological rhythms. Athletes take a nap to counteract afternoon circadian nadir, in prevision of disturbed sleep. This study examined the effects of brief post-lunch nap on vigilance in young and healthy athletes.”

“The P300 components, physiological and cognitive performances were assessed either after nap or rest, following a night of normal sleep or simulated jet lag condition (5-h advance-Jet Lag Condition).”
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“Napping positively impacts on cognitive processing, especially when subjects are on normal sleep schedules. A nap should be planned for athletes whose performance requires speedy and accurate decisions.”
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E.P.H.Bourdin
Effects of a 20-Min Nap Post Normal and Jet Lag Conditions on P300 Components in Athletes
International Journal Of Sports Medicine — Volume 39 #7 — July 2018 — page 508