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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.
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Extreme Physiology & Medicine

ISSN: 2046-7648

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