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Table 6 Additional physiological variables

From: The physiological effects of hypobaric hypoxia versus normobaric hypoxia: a systematic review of crossover trials

Outcome Author and year Duration of exposure (h:min) Hypobaric hypoxia result [mean (SD)] Normobaric hypoxia result [mean (SD)] Difference (HH − NH) P value Direction of difference NH compared to HH
Exhaled NO (PE NO)        
  Hemmingsson 2009 00:10 at each ascending altitude - - 33% mean reduction (at 5,000 m) 0.002 NH > HH
Faiss 2013 01:00 9.5 (5.0) 14.9 (9.2) −5.4 <0.01 NH > HH
Faiss 2013 08:00 8.8 (5.3) 14.1 (7.4) −5.3 <0.01 NH > HH
Faiss 2013 16:00 7.9 (4.5) 14.7 (8.6) −6.8 <0.01 NH > HH
Faiss 2013 24:00:00 8.9 (5.4) 15.7 (8.7) −5.8 <0.01 NH > HH
RQ        
  Self 2011 00:05 2.37 (0.53) 1.41 (0.15) 0.96 0.005 HH > NH
Forced vascular conductance        
  Miyagawa 2010 01:00-01:40 - - - >0.05 NS
Sweat rate        
  Miyagawa 2010 01:00-01:40 - - - >0.05 NS
Oesophageal temperature thresholds for increasing forearm skin vascular conductance        
  Miyagawa 2010 01:00-01:40 - - - >0.05 NS
Oesophageal temperature thresholds for increasing sweat rate        
  Miyagawa 2010 01:00-01:40 - - - >0.05 NS
Oesophageal temperature        
  Miyagawa 2010 01:05 36.63 36.61 0.02 >0.05 NS
Miyagawa 2010 01:10 37.12 37.11 0.01 >0.05 NS
Miyagawa 2010 01:40 37.95 37.96 −0.01 >0.05 NS
Skin temperature        
  Miyagawa 2010 01:05 33.37 33.47 −0.1 >0.05 NS
Miyagawa 2010 01:10 33.35 33.43 −0.08 >0.05 NS
Miyagawa 2010 01:40 34.44 34.59 −0.15 >0.05 NS
Urine vol (ml)        
  Loeppky 2005a 10:00 - - - 0.005 HH > NH
Tucker 1983b 02:20 including 00:15 buildd −1.6 0.1 −1.7 - NH > HH
Plasma volume        
  Miyagawa 2010 01:00-01:40 - - - >0.05 NS
Loeppky 2005 10:00 - - −6% 0.002** HH > NH
GFR        
  Loeppky 2005 10:00 - - - >0.05 NS
Plasma K+        
  Loeppky 2005 10:00 - - - 0.003 NH > HH
Plasma Na+        
  Loeppky 2005 10:00 - - - 0.006 NH > HH
Plasma renin activity (PRA)        
  Loeppky 2005a 10:00 - - - <0.05 HH > NH
Plasma aldosterone        
  Loeppky 2005a 10:00 - - - <0.001 NH > HH
Free water clearance (CH2O)        
  Loeppky 2005a 10:00 - - - <0.05 HH > NH
ACTH        
  Loeppky 2005a 10:00 - - - 0.18 NS
ADH        
  Loeppky 2005 10:00 - - - >0.05 NS
ANP        
  Loeppky 2005* 10:00 - - - 0.97 NS
Blood base excess        
  Loeppky 2005 10:00 - - - >0.05 NS
Urine Na+/K+        
  Loeppky 2005 10:00 - - - 0.7 NS
Catecholamines        
  Miyagawa 2010 01:00-01:40 - - - >0.05 NS
Loeppky 2005 10:00 - - - 0.43 NS
Haematocrit        
  Miyagawa 2010 01:00-01:40 - - - >0.05 NS
Tucker 1983b 02:20 including 00:15 buildd 0.7 0.7 0   NS
Haemoglobin concentration        
  Savourey 2007 00:10 buildd, 00:05 - - - >0.05 NS
Savourey 2007 00:10 buildd, 00:30 - - - >0.05 NS
Miyagawa 2010 01:00-01:40 - - - >0.05 NS
Plasma osmolarity (mOsm)        
  Miyagawa 2010 01:00-01:40 - - - >0.05 NS
Tucker 1983b 02:20 including 00:15 buildd −0.4 −1 0.6 - HH > NH
pH        
  Savourey 2003 00:10 buildd, 00:30 7.46 (SEM 0.03) 7.44 (SEM 0.02) 0.02 ≤0.05 Borderline HH > NH
Savourey 2007 00:10 buildd, 00:30 7.45 (0.04) 7.44 (0.04) 0.01 0.02 HH > NH
CAL subjects        
  Naughton 1995 00:52 - - −0.02 >0.05 NS
Control subjects        
  Naughton 1995 00:52 - - 0.01 >0.05 NS
Tucker 1983d 02:20 including 00:15 buildd 0.047 0.015 0.032 - HH > NH
Faiss 2013 24:00:00 - - - <0.01 NH > HH
Urine osmolarity (mOsm)        
  Tucker 1983c 02:20 including 00:15 buildb 15 0.1 14.9 - HH > NH
Lactate mmol/kgH2O        
  Miyagawa 2010 01:00-01:40 - - - >0.05 NS
Blood NO metabolites        
  Faiss 2013 01:00 31.6 (19.6) 27.7 (7.3) 3.9 <0.01 HH > NH
Faiss 2013 08:00 28.1 (18.9) 32.7 (9.7) −4.6 <0.01 NH > HH
Faiss 2013 16:00 24.2 (16.3) 30.2 (7.1) −6 <0.01 NH > HH
Faiss 2013 24:00 22.85 (16.2) 28.9 (6.9) −6.05 <0.01 NH > HH
GPX (% baseline)        
  Faiss 2013 01:00 114 (26) 111 (30) 3 >0.05 NS
Faiss 2013 08:00 85 (27) 123 (23) −37 >0.05 NS
Faiss 2013 16:00 105 (43) 107 (21) −2 >0.05 NS
Faiss 2013 24:00 103 (43) 107 (21) −4 >0.05 NS
MDA (% baseline)        
  Faiss 2013 01:00 117 (40) 92 (36) 25 >0.05 NS
Faiss 2013 08:00 103 (62) 111 (35) −8 >0.05 NS
Faiss 2013 16:00 111 (56) 116 (55) −5 >0.05 NS
Faiss 2013 24:00 108 (52) 97 (51) 11 >0.05 NS
Nitrotyrosine (% baseline)        
  Faiss 2013 01:00 86 (16) 105 (26) −19 >0.05 NS
Faiss 2013 08:00 77 (35) 75 (37) 2 >0.05 NS
Faiss 2013 16:00 91 (20) 98 (16) −7 >0.05 NS
Faiss 2013 24:00 75 (40) 87 (25) −12 >0.05 NS
Plasma advanced oxidation protein products        
  Faiss 2013 01:00 120% 13% 107% - NH > HH
Faiss 2013 24:00 260% 88% 172% - NH > HH
Superoxide dismutase Faiss 2013 24:00 - - 37% - NH > HH
  1. This table lists all the values of all other the measured physiological variables.
  2. NS insignificant, SEM Standard Error of the Mean.
  3. aMeasured 2 h after exposure.
  4. bDifference from controls.
  5. cSubjects were gradually exposed increasing levels of hypoxia over the stated time until the target hypoxic dose was reached.
  6. dWhen the subjects entered the chamber, the environmental conditions were that of normal sea level but then were gradually made more hypoxic over the specified amount of time until the target hypoxic dose was reached.
  7. *P value calculated including hypobaric normoxia.
  8. **P value calculated including hypobaric normoxia and after 3 h.