MUSCLE PHYSIOLOGY IN HYPOXIA AEROBIC AND ANAEROBIC METABOLISM

34 Pages·2005·0.93 MB·English

MUSCLE PHYSIOLOGY IN
HYPOXIA
AEROBIC AND ANAEROBIC
METABOLISM
Paolo Cerretelli
Dipartimento di Scienze e Tecnologie
Biomediche Università di MIlano
Arica, April 2005
Barometric Pressure (P ) and P O as a
B A
2
function of altitude
800
700 P
B
600
500
) Eq.Zuntz
r
r
o
T
400
( Mt. Everest
B
P P =253 Torr
ICAO B
300
200
)
r
r
50 o
T
P O (
A 2 O2
37.6
0 A
P
0 2 4 6 8 10
Altitude (km)
Alveolar gas composition in acute hypoxia
and after acclimatization
40 Acute Hypoxia
A c c l i m a t i z e d S u b j e c t
30
)
r
r
o
T
(
2 20
O R
PCA 10 R= R= 0 0,=8, 51 8 . 8 8. R = 0,85 6.0 R = 0,85 4.000
8 5 2 0 m
5 0 0 0
0
m m
m
0
20 30 40 50 60 70 80 90 100
P O (Torr)
A
2
Alveolar and arterial blood gas pressures at
the summit of Mt. Everest (8850m)
Arterial
Barometric Alveolar
Altitude Inspired
pressure PO2
(m) PO2 PO2 PCO2 pH SaO2
(torr) (torr)
(torr)
8848 253 43 35 28 7.5 > 7.7 70
Sea
760 149 100 95 40 7.4 97
Level
Blood gas partial pressures and HbO
2
saturation as a function of altitude
100 100
80
) 80
r
r
o )
t
t a
(
s
2
O 60 PaO %
C PaCO2 60 (
a 2 2
P O
HbO
2 2 b
O H
40
a
P 40
20
20
0 1000 2000 3000 4000 5000 6000 7000 8000
Altitudine (m)
Arterial blood pH as a function of altitude
7.8
pHa
7,7
7,6
7,5
7,4
4 5 6 7 8 9
Altitude (km)
.
VO max as a function of altitude in acute
2
and chronic hypoxia in caucasian subjects
100
80
)
l
s
a

%
60
(

x
a
m
40
2
O
.
V
Chronic Hypoxia
20
Acute Hypoxia
0
0 1 2 3 4 5 6 7 8 9
Altitude (km)
.
VO max as a function of time before,
2
during and after exposure to 5050m
.
5
VO max (l·min-1)
2
4
3
2
1
0
1 1 2 3 2 3 4 5 6
L T T T L L L L L
S L L L S S S S S
A A A
.
% reduction of VO max as a function
2
of altitude
100 Operation Everest II
Tibetans 2nd generation
90
80
x
a 70
m
.O2 60
V
50
.
l
.
s
40
%
30
20
10
0 2 4 6 8 10
ALTITUDE (km)
.
ΔVO max (%) in different ethnic groups
2
at 5050 m
100 Sea level
92
Tibetans 2nd
)
% 80 83 Sherpas
74
( Skyrunners

x
a 60 60
Caucasians 31days
m
53
Caucasians 11days
2
O
. 40
V
Δ
20
0
0 1 2 3 4 5 6
Altitude (km)