Author(s): WADA, T., ITO, K.1, YAMAMOTO, N.2, TAGAKI, S.1, KASHIWAGI, Y.3, HIRANO, T.4, NISHINO, S.5, Institution: KOKUSHIKAN UNIVERSITY, Country: JAPAN, Abstract-ID: 1334

INTRODUCTION:
Daytime naps are widely used by competitive swimmers to maintain performance during multi-race competitions. However, the influence of the nap sleep environment on sleep quality and post-nap performance has not been sufficiently investigated. This study examined the effects of different nap sleep environments—a yoga mat and a high-resilience mattress (airweave, with high rebound and high heat-exchange capability)—on sleep architecture and subsequent cognitive and physical performance in collegiate swimmers.
METHODS:
Twelve male collegiate swimmers (18–20 years) participated in a crossover design. Following morning training sessions, participants completed a 30-min nap on either a yoga mat or a high-resilience mattress on separate days. Sleep stages during naps were assessed using portable electroencephalography (EEG). Post-nap performance was evaluated using a Psychomotor Vigilance Test (PVT) for reaction time and a Wingate Anaerobic Test for power output. Comparisons were made between pre- and post-nap measurements and between sleep conditions.
RESULTS:
EEG analysis showed that naps on the high-resilience mattress resulted in a greater proportion of N3 (slow-wave sleep) and wakefulness, whereas naps on the yoga mat were characterized by a higher proportion of N1 sleep. Both conditions demonstrated a reduction in PVT error rates after the nap; however, improvements in reaction time were limited. In contrast, Wingate test results indicated higher peak and mean power values following naps on the high-resilience mattress compared with the yoga mat condition.
CONCLUSION:
The findings suggest that the nap sleep environment influences nap sleep architecture and post-nap performance. A high-resilience mattress may be more beneficial when post-nap performance requires high power output, whereas lighter sleep environments may suffice for tasks emphasizing alertness. Selecting nap environments according to performance demands may enhance competitive conditioning strategies in swimmers.