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Douglas Potter and Denis Keeling

The effects of exercise and circadian rhythms on memory function were explored in a group of shift workers (mean age 32 yrs). A variant of the Auditory-Verbal Learning Test was used to test memory for word lists at 9:30 a.m. and 12:30, 3:30, and 6:30 p.m. in a repeated-measures design. Without exercise there was clear evidence of a circadian rhythm in memory performance, with peak performance occurring at 12:30 and poorest performance at 3:30. A brisk 10-min walk followed by a 15- to 30-min recovery period resulted in significant improvement in memory recall at all time periods except 12:30. The results of the AVLT task suggest an improvement in both working memory and long-term memory performance. Rhythmic changes in serotonin, epinephrine, norepinephrine, and acetylcholine levels all affect cortical arousal and cognitive function. Exercise may have resulted in altered levels of these neurotransmitters, increased glucose, oxygen, or nutrient levels, or from temporary changes in growth hormone or brain-derived neurotropic factor levels resulting in increased synaptogenesis and neurogenesis. The physiological basis of this temporary improvement in memory remains to be determined, but this simple behavioral intervention may have widespread application in improving memory function in all sections of the population including children and the elderly.

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David P. Looney, Mark J. Buller, Andrei V. Gribok, Jayme L. Leger, Adam W. Potter, William V. Rumpler, William J. Tharion, Alexander P. Welles, Karl E. Friedl and Reed W. Hoyt

) such as solely heart rate ( Buller et al., 2013 ). While the majority of estimation methods for CT have focused on stressed environments during exercise conditions, resting CT modeling is particularly valuable for research and clinical purposes including circadian rhythm monitoring. Circadian rhythm

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W. Christopher Winter, William R. Hammond, Noah H. Green, Zhiyong Zhang and Donald L. Bliwise

Purpose:

The effect of travel on athletic performance has been investigated in previous studies. The purpose of this study was to investigate this effect on game outcome over 10 Major League Baseball (MLB) seasons.

Methods:

Using the convention that for every time zone crossed, synchronization requires 1 d, teams were assigned a daily number indicating the number of days away from circadian resynchronization. With these values, wins and losses for all games could be analyzed based on circadian values.

Results:

19,079 of the 24,121 games (79.1%) were played between teams at an equal circadian time. The remaining 5,042 games consisted of teams playing at different circadian times. The team with the circadian advantage won 2,620 games (52.0%, P = .005), a winning percentage that exceeded chance but was a smaller effect than home field advantage (53.7%, P < .0001). When teams held a 1-h circadian advantage, winning percentage was 51.7% (1,903–1,781). Winning percentage with a 2-h advantage was 51.8% (620–578) but increased to 60.6% (97–63) with a 3-h advantage (3-h advantage > 2-hadvantage = 1-h advantage, P = .036). Direction of advantage showed teams traveling from Western time zones to Eastern time zones were more likely to win (winning percentage = .530) than teams traveling from Eastern time zones to Western time zones (winning percentage = .509) with a winning odds 1.14 (P = .027).

Conclusion:

These results suggest that in the same way home field advantage influences likelihood of success, so too does the magnitude and direction of circadian advantage. Teams with greater circadian advantage were more likely to win.

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Hugh H.K. Fullagar, Rob Duffield, Sabrina Skorski, Aaron J. Coutts, Ross Julian and Tim Meyer

While the effects of sleep loss on performance have previously been reviewed, the effects of disturbed sleep on recovery after exercise are less reported. Specifically, the interaction between sleep and physiological and psychological recovery in team-sport athletes is not well understood. Accordingly, the aim of the current review was to examine the current evidence on the potential role sleep may play in postexercise recovery, with a tailored focus on professional team-sport athletes. Recent studies show that team-sport athletes are at high risk of poor sleep during and after competition. Although limited published data are available, these athletes also appear particularly susceptible to reductions in both sleep quality and sleep duration after night competition and periods of heavy training. However, studies examining the relationship between sleep and recovery in such situations are lacking. Indeed, further observational sleep studies in team-sport athletes are required to confirm these concerns. Naps, sleep extension, and sleep-hygiene practices appear advantageous to performance; however, future proof-of-concept studies are now required to determine the efficacy of these interventions on postexercise recovery. Moreover, more research is required to understand how sleep interacts with numerous recovery responses in team-sport environments. This is pertinent given the regularity with which these teams encounter challenging scenarios during the course of a season. Therefore, this review examines the factors that compromise sleep during a season and after competition and discusses strategies that may help improve sleep in team-sport athletes.

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Chris Brogden, Kelly Marrin, Richard Page and Matt Greig

of movement screening is fundamental to the subsequent design of prehabilitation and injury management strategies. Circadian rhythm is a term used to describe variations in many human physiological variables 8 and factors influencing athletic performance, relative to time of day. 9 , 10 It has been

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Tzai-Li Li and Michael Gleeson

This study compared immunoendocrine responses to a single bout of prolonged cycling at different times of day and to a 2nd bout of cycling at the same intensity on the same day. In a counterbalanced design, 8 men participated in 3 experimental trials separated by at least 4 d. In the afternoon exercise-only trial, subjects cycled for 2 h at 60% VO2max starting at 14:00. In the other 2 trials, subjects performed either 2 bouts of cycling at 60% VO2max for 2 h (starting at 09:00 and 14:00) or a separate resting trial. The single bout of prolonged exercise performed in the afternoon induced a larger neutrophilia and monocy-tosis than the identical bout of morning exercise, possibly the result of reduced carbohydrate availability and the circadian rhythm in cortisol levels. The 2nd prolonged exercise bout caused greater immunoendocrine responses but lower plasma glucose levels and neutrophil function compared with the 1st bout.

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. Schneider * 3 2005 27 1 111 116 10.1123/jsep.27.1.111 Research Effects of Moderate Exercise and Circadian Rhythms on Human Memory Douglas Potter 1 Denis Keeling 2 3 2005 27 1 117 125 10.1123/jsep.27.1.117 The Digest The Digest David Lavallee Mark Beauchamp Melissa Day Didier Delignieres

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Lara A. Carlson, Kaylee M. Pobocik, Michael A. Lawrence, Daniel A. Brazeau and Alexander J. Koch

Melatonin’s response to exercise in athletes is important to understand to implement best training practices for promoting sleep. Melatonin (N-acetyl-5-methoxytryptamine) is known to influence the sleep–wake cycle, 8 and its secretion by the pinealocytes influences the circadian rhythm. 8 – 10 Melatonin

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://www.sbm.org/meetings/ for more information. May 28 to June 1, 2019, Orlando, FL, USA The 66th annual meeting of the American College of Sports Medicine (ACSM) will be held in conjunction with the 10th World Congress on Exercise is Medicine and the World Congress on the Basic Science of Exercise, Circadian Rhythms and Sleep

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Francisco J. Amaro-Gahete, Lucas Jurado-Fasoli, Alejandro R. Triviño, Guillermo Sanchez-Delgado, Alejandro De-la-O, Jørn W. Helge and Jonatan R. Ruiz

. 2015 ; 45 : 37 – 56 . doi:10.1007/s40279-014-0246-y 10.1007/s40279-014-0246-y 25164465 7. Drust B , Waterhouse J , Atkinson G , Edwards B , Reilly T . Circadian rhythms in sports performance—an update . Chronobiol Int . 2005 ; 22 : 21 – 44 . PubMed ID: 15865319 doi:10.1081/CBI