Northumbria University has developed Northumbria Research Link (NRL) to enable users to access the University's research output. Copyright © and moral rights for items on NRL are retained by the individual author(s) and/or other copyright owners. Single copies of full items can be reproduced, displayed or performed, and given to third parties in any format or medium for personal research or study, educational, or not-for-profit purposes without prior permission or charge, provided the authors, title and full bibliographic details are given, as well as a hyperlink and/or URL to the original metadata page. The content must not be changed in any way. Full items must not be sold commercially in any format or medium without formal permission of the copyright holder. The full policy is available online: http://nrl.northumbria.ac.uk/policies.html This document may differ from the final, published version of the research and has been made available online in accordance with publisher policies. To read and/or cite from the published version of the research, please visit the publisher's website (a subscription may be required.) A systematic meta-regression analysis of the effects of acute hypoxia on the performance of 17 central executive and non-executive tasks, and the effects of the moderating variables, arterial 18 partial pressure of oxygen (PaO2) and hypobaric versus normobaric hypoxia, was undertaken. 19Studies were included if they were performed on healthy humans; within-subject design was 20 used; data were reported giving the PaO2 or that allowed the PaO2 to be estimated (e.g. arterial 21 oxygen saturation and/or altitude); and the duration of being in a hypoxic state prior to cognitive 22 testing was ≤ 6 days. Twenty-two experiments met the criteria for inclusion and demonstrated a 23 moderate, negative mean effect size (g = -.49, 95% CI -0.64 to -0.34, p < .001). There were no 24 significant differences between central executive and non-executive, perception/attention and 25 short-term memory, tasks. Low (35-60 mmHg) PaO2 was the key predictor of cognitive 26 performance (R 2 = .45, p < .001) and this was independent of whether the exposure was in 27 hypobaric hypoxic or normobaric hypoxic conditions. 28

HH competition encourages participants to increase their performance. This occurs primarily via an increased anaerobic energy yield, which seems to be centrally mediated, and is consistent with the concept of a physiologic reserve.

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We examined the effect of short-term heat acclimation with permissive dehydration (STHADe) on heat acclimation (HA) and cycling performance in a temperate environment.

What is the topic of this review? This is the first review to look across the broad field of 'cold water immersion' and to determine the threats and benefits associated with it as both a hazard and a treatment. What advances does it highlight? The level of evidence supporting each of the areas reviewed is assessed. Like other environmental constituents, such as pressure, heat and oxygen, cold water can be either good or bad, threat or treatment, depending on circumstance. Given the current increase in the popularly of open cold water swimming, it is timely to review the various human responses to cold water immersion (CWI) and consider the strength of the claims made for the effects of CWI. As a consequence, in this review we look at the history of CWI and examine CWI as a precursor to drowning, cardiac arrest and hypothermia. We also assess its role in prolonged survival underwater, extending exercise time in the heat and treating hyperthermic casualties. More recent uses, such as in the prevention of inflammation and treatment of inflammation-related conditions, are also considered. It is concluded that the evidence base for the different claims made for CWI are varied, and although in most instances there seems to be a credible rationale for the benefits or otherwise of CWI, in some instances the supporting data remain at the level of anecdotal speculation. Clear directions and requirements for future research are indicated by this review.

Background: Dehydration appears prevalent, costly and associated with adverse outcomes. We sought to generate consensus on such key issues and elucidate need for further scientific enquiry. Materials and Methods: A modified Delphi process combined expert opinion and evidence appraisal. 12 relevant experts addressed dehydration's definition, objective markers and impact on physiology and outcome. Results: Fifteen consensus statements and seven research recommendations were generated. Key findings, evidenced in detail, were that there is no universally-accepted definition for dehydration; hydration assessment is complex and requires combining physiological and laboratory variables; 'dehydration' and 'hypovolaemia' are incorrectly used interchangeably; abnormal hydration status includes relative and/or absolute abnormalities in body water and serum/plasma osmolality (pOsm); raised pOsm usually indicates dehydration; direct measurement of pOsm is the gold standard for determining dehydration; pOsm >300 and ≤280 mOsm/kg classifies a person as hyper or hypo-osmolar; outside extremes, signs of adult dehydration are subtle and unreliable; dehydration is common in hospitals and care homes and associated with poorer outcomes. Discussion: Dehydration poses risk to public health. Dehydration is under-recognised and poorly managed in hospital and community-based care. Further research is required to improve assessment and management of dehydration and the authors have made recommendations to focus academic endeavours.

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