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Sports 2018, 6(2), 42;

The Effects of Sleep Extension on Sleep, Performance, Immunity and Physical Stress in Rugby Players

Faculty of Sport and Recreation, Auckland University of Technology, Auckland 0627, New Zealand
Nutrition Department, Singapore Sport Institute, Singapore 397630, Singapore
Physiology Department, Australian Institute of Sport, Canberra 2617, Australia
Sports Research Institute New Zealand, Auckland University of Technology, Auckland 0627, New Zealand
Faculty of Health, Sport and Human Performance, University of Waikato, Hamilton 3240, New Zealand
Author to whom correspondence should be addressed.
Received: 25 March 2018 / Revised: 1 May 2018 / Accepted: 1 May 2018 / Published: 10 May 2018
(This article belongs to the Special Issue Fatigue and Recovery in Football)
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(1) Background: The purpose of the present study was to examine the efficacy of sleep extension in professional rugby players. The aims were to: (i) characterise sleep quantity in elite rugby players and determine changes in immune function and stress hormone secretion during a pre-season training programme; (ii) evaluate the efficacy of a sleep extension intervention in improving sleep, markers of physical stress, immune function and performance. (2) Methods: Twenty five highly trained athletes from a professional rugby team (age (mean ± SD) 25 ± 2.7 years; height 1.87 ± 0.07 m; weight 105 ± 12.1 kg) participated in a six week pre-post control-trial intervention study. Variables of sleep, immune function, sympathetic nervous activity, physiological stress and reaction times were measured. (3) Results: Sleep extension resulted in a moderate improvement in sleep quality scores ([mean; ± 90% confidence limits] −24.8%; ± 54.1%) and small to moderate increases in total sleep time (6.3%; ± 6.3%) and time in bed (7.3%; ± 3.6%). In addition, a small decrease in cortisol (−18.7%; ± 26.4%) and mean reaction times (−4.3%; ± 3.1%) was observed following the intervention, compared to the control. (4) Conclusions: Professional rugby players are at risk of poor sleep during pre-season training, with concomitant rises in physical stress. Implementing a sleep extension programme among professional athletes is recommended to improve sleep, with beneficial changes in stress hormone expression and reaction time performance. View Full-Text
Keywords: sleep extension; collision sports; physical stress; recovery; performance sleep extension; collision sports; physical stress; recovery; performance
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Swinbourne, R.; Miller, J.; Smart, D.; Dulson, D.K.; Gill, N. The Effects of Sleep Extension on Sleep, Performance, Immunity and Physical Stress in Rugby Players. Sports 2018, 6, 42.

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