Oxygen transport: air to muscle cell

被引:32
作者
Richardson, RS [1 ]
机构
[1] Univ Calif San Diego, Dept Med 0623, La Jolla, CA 92093 USA
关键词
hypoxia; myoglobin saturation; quadriceps; human; exercise;
D O I
10.1097/00005768-199801000-00008
中图分类号
G8 [体育];
学科分类号
04 ; 0403 ;
摘要
The series of drops in PO2 which comprise the oxygen cascade from the air to mammalian tissue can provide useful information about O-2 transport during exercise in both health and disease, but the complete cascade has been challenging to study in vivo. This paper reviews a series of in vivo human knee-extensor studies which focus on the determinants of maximal O-2 consumption ((V)over dot O-2max) in exercising muscle and concludes with a characterization of the complete O-2 cascade in maximally exercising human muscle. Specifically, three issues have been addressed: 1) determinants of O-2 extraction under conditions of very high muscle blood flow; 2) the role of O-2 diffusivity in determining the maximum O-2 flux rate ((V)over dot O-2max); and 3) myoglobin associated PO2 as a indicator of O-2 transport and cellular respiration rate. In summary, these investigations demonstrate that in humans O-2 extraction can be uncompromised despite high mass specific blood flows, perhaps in part because of an increased capillary density in exercise trained subjects. Exercise in hypoxia reduces (V)over dot O-2max, but as calculated diffusability of O-2 from blood to muscle is constant this suggests that a fixed O-2 diffusivity plays a key role in limiting maximal O-2 uptake. Supporting evidence of a substantial PO2 gradient from blood to myoglobin also suggests a resistance to the diffusion of O-2 between red cell and sarcolemma, which may be present even al submaximal exercise. Finally, the proportionate relationship between myoglobin associated PO2 and (V)over dot O-2max in conditions of normoxia and hypoxia additionally supports the hypothesis that maximal respiratory rate of muscle cells is limited by O-2 supply.
引用
收藏
页码:53 / 59
页数:7
相关论文
共 30 条
[1]   MAXIMAL PERFUSION OF SKELETAL-MUSCLE IN MAN [J].
ANDERSEN, P ;
SALTIN, B .
JOURNAL OF PHYSIOLOGY-LONDON, 1985, 366 (SEP) :233-249
[2]   CAPILLARY SUPPLY OF QUADRICEPS FEMORIS MUSCLE OF MAN - ADAPTIVE RESPONSE TO EXERCISE [J].
ANDERSEN, P ;
HENRIKSSON, J .
JOURNAL OF PHYSIOLOGY-LONDON, 1977, 270 (03) :677-&
[3]   DYNAMIC KNEE EXTENSION AS MODEL FOR STUDY OF ISOLATED EXERCISING MUSCLE IN HUMANS [J].
ANDERSEN, P ;
ADAMS, RP ;
SJOGAARD, G ;
THORBOE, A ;
SALTIN, B .
JOURNAL OF APPLIED PHYSIOLOGY, 1985, 59 (05) :1647-1653
[4]  
Bertinini I., 1986, NMR PARAMAGNETIC MOL
[5]   SEPARATE MEASURES OF ATP UTILIZATION AND RECOVERY IN HUMAN SKELETAL-MUSCLE [J].
BLEI, ML ;
CONLEY, KE ;
KUSHMERICK, MJ .
JOURNAL OF PHYSIOLOGY-LONDON, 1993, 465 :203-222
[6]   CAPILLARY SUPPLY OF SKELETAL-MUSCLE FIBERS IN UNTRAINED AND ENDURANCE-TRAINED MEN [J].
BRODAL, P ;
INGJER, F ;
HERMANSEN, L .
AMERICAN JOURNAL OF PHYSIOLOGY, 1977, 232 (06) :H705-H712
[7]  
FOLKOW B, 1968, Microvascular Research, V1, P1, DOI 10.1016/0026-2862(68)90002-2
[8]  
GAYESKI TEI, 1988, ADV EXP MED BIOL, V247, P591
[9]   LOCAL XENON 133 CLEARANCE FROM QUADRICEPS MUSCLE DURING EXERCISE IN MAN [J].
GRIMBY, G ;
HAGGENDA.E ;
SALTIN, B .
JOURNAL OF APPLIED PHYSIOLOGY, 1967, 22 (02) :305-&
[10]  
Groebe K., 1991, LUNG SCI FDN, P1489