title: Markers of physiological stress during exercise under conditions of normoxia, normobaric hypoxia, hypobaric hypoxia, and genuine high altitude.
abstract: OBJECTIVE
  To investigate whether there is a differential response at rest and following exercise to conditions of genuine high altitude (GHA), normobaric hypoxia (NH), hypobaric hypoxia (HH), and normobaric normoxia (NN).
  
  
  METHODS
  Markers of sympathoadrenal and adrenocortical function [plasma normetanephrine (PNORMET), metanephrine (PMET), cortisol], myocardial injury [highly sensitive cardiac troponin T (hscTnT)], and function [N-terminal brain natriuretic peptide (NT-proBNP)] were evaluated at rest and with exercise under NN, at 3375 m in the Alps (GHA) and at equivalent simulated altitude under NH and HH. Participants cycled for 2 h [15-min warm-up, 105 min at 55% Wmax (maximal workload)] with venous blood samples taken prior (T0), immediately following (T120) and 2-h post-exercise (T240).
  
  
  RESULTS
  Exercise in the three hypoxic environments produced a similar pattern of response with the only difference between environments being in relation to PNORMET. Exercise in NN only induced a rise in PNORMET and PMET.
  
  
  CONCLUSIONS
  Biochemical markers that reflect sympathoadrenal, adrenocortical, and myocardial responses to physiological stress demonstrate significant differences in the response to exercise under conditions of normoxia versus hypoxia, while NH and HH appear to induce broadly similar responses to GHA and may, therefore, be reasonable surrogates.
authors.affiliation: Royal Centre for Defence Medicine, Birmingham, UK. DoctorDRWoods@aol.com.|Research Institute, for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK. DoctorDRWoods@aol.com.|University of Newcastle, Newcastle upon Tyne, UK. DoctorDRWoods@aol.com.|Northumbria and Newcastle NHS Trusts, Wansbeck General and Royal Victoria Infirmary, Newcastle, UK. DoctorDRWoods@aol.com.
authors.forename: David Richard
authors.initials: DR
authors.lastname: Woods
authors.affiliation: Research Institute, for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK.
authors.forename: John Paul
authors.initials: JP
authors.lastname: O'Hara
authors.affiliation: Research Institute, for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK.|Department of Cardiology, Poole Hospital NHS Foundation Trust, Poole, UK.|Department of Postgraduate Medical Education, Bournemouth University, Poole, UK.
authors.forename: Christopher John
authors.initials: CJ
authors.lastname: Boos
authors.affiliation: RAF Centre of Aviation Medicine, RAF Henlow, Bedfordshire, SG16 6DN, UK.
authors.forename: Peter David
authors.initials: PD
authors.lastname: Hodkinson
authors.affiliation: Research Institute, for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK.
authors.forename: Costas
authors.initials: C
authors.lastname: Tsakirides
authors.affiliation: Royal Centre for Defence Medicine, Birmingham, UK.|Imperial College London, London, UK.|Charing Cross Hospital, London, UK.
authors.forename: Neil Edward
authors.initials: NE
authors.lastname: Hill
authors.affiliation: Pathology, Poole Hospital NHS Foundation Trust, Poole, UK.
authors.forename: Darren
authors.initials: D
authors.lastname: Jose
authors.affiliation: Pathology, Poole Hospital NHS Foundation Trust, Poole, UK.
authors.forename: Amanda
authors.initials: A
authors.lastname: Hawkins
authors.affiliation: Department of Biochemistry, Freeman Hospital, Freeman Road, Newcastle upon Tyne, UK.
authors.forename: Kelly
authors.initials: K
authors.lastname: Phillipson
authors.affiliation: Royal Centre for Defence Medicine, Birmingham, UK.
authors.forename: Antonia
authors.initials: A
authors.lastname: Hazlerigg
authors.affiliation: School of Social and Health Sciences, Leeds Trinity University, Leeds, UK.
authors.forename: Nicola
authors.initials: N
authors.lastname: Arjomandkhah
authors.affiliation: Research Institute, for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK.
authors.forename: Liam
authors.initials: L
authors.lastname: Gallagher
authors.affiliation: Royal Centre for Defence Medicine, Birmingham, UK.
authors.forename: David
authors.initials: D
authors.lastname: Holdsworth
authors.affiliation: Research Institute, for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK.
authors.forename: Mark
authors.initials: M
authors.lastname: Cooke
authors.affiliation: RAF Centre of Aviation Medicine, RAF Henlow, Bedfordshire, SG16 6DN, UK.
authors.forename: Nicholas Donald Charles
authors.initials: NDC
authors.lastname: Green
authors.affiliation: Royal Centre for Defence Medicine, Birmingham, UK.|Research Institute, for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK.|James Cook University Hospital, Middlesbrough, TS4 3BW, UK.
authors.forename: Adrian
authors.initials: A
authors.lastname: Mellor
mesh_terms: D000328:Adult; D000532:Altitude Sickness / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D015444:Exercise; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D000860:Hypoxia / Q000097:blood*; D008297:Male; D008676:Metanephrine / Q000097:blood; D020097:Natriuretic Peptide, Brain / Q000097:blood; D013312:Stress, Physiological; D020107:Troponin T / Q000097:blood
chemical_list: D015415:Biomarkers; D020107:Troponin T; D020097:Natriuretic Peptide, Brain; D008676:Metanephrine; D006854:Hydrocortisone
keywords: Adrenal; Cardiac; Exercise; High altitude; Hypobaric hypoxia; NT-proBNP; Normobaric hypoxia