PMID- 9707640
OWN - NLM
STAT- MEDLINE
DCOM- 19980917
LR  - 20190501
IS  - 0027-8424 (Print)
IS  - 1091-6490 (Electronic)
IS  - 0027-8424 (Linking)
VI  - 95
IP  - 17
DP  - 1998 Aug 18
TI  - Carbohydrate utilization during exercise after high-altitude acclimation: a new 
      perspective.
PG  - 10288-93
AB  - At high altitude (HA), carbohydrate (CHO) is thought to be the preferred fuel 
      because of its higher yield of ATP per mole of O2. We used indirect calorimetry 
      and D-[6-3H]glucose infusions to determine total CHO and circulatory glucose 
      utilization during exercise in HA-acclimated and sea level (SL) rats. We 
      hypothesized that the percent contribution of CHO to total metabolism (VO2) is 
      determined by exercise intensity relative to an aerobic maximum (% VO2max). HA 
      rats run under hypoxia (FIO2 = 0.12) showed a decrease in VO2max compared with SL 
      (67.55 +/- 1.26 vs. 89.30 +/- 1.23 ml kg-1 min-1). When exercised at 60% of their 
      respective VO2max, both groups showed the same relative use of CHO (38 +/- 3% and 
      38 +/- 5% of VO2, at the beginning of exercise, in HA and SL, respectively). In 
      both HA and SL, circulatory glucose accounted for approximately 20% of VO2, the 
      balance was provided by muscle glycogen (approximately 18% of VO2). After 20 min 
      at a higher intensity of 80% VO2max, 54 +/- 5% (HA) and 59 +/- 4% (SL) of VO2 was 
      accounted for by CHO. We conclude the following: (i) the relative contributions 
      of total CHO, circulatory glucose, and muscle glycogen do not increase after HA 
      acclimation because the O2-saving advantage of CHO is outweighed by limited CHO 
      stores; and (ii) relative exercise intensity is the major determinant of 
      metabolic fuel selection at HA, as well as at SL.
FAU - McClelland, G B
AU  - McClelland GB
AD  - Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 
      1Z4. mcleland@unixg.ubc.ca
FAU - Hochachka, P W
AU  - Hochachka PW
FAU - Weber, J M
AU  - Weber JM
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Proc Natl Acad Sci U S A
JT  - Proceedings of the National Academy of Sciences of the United States of America
JID - 7505876
RN  - 0 (Blood Glucose)
RN  - 0 (Dietary Sucrose)
RN  - 8L70Q75FXE (Adenosine Triphosphate)
RN  - 9005-79-2 (Glycogen)
RN  - IY9XDZ35W2 (Glucose)
RN  - S88TT14065 (Oxygen)
SB  - IM
MH  - Acclimatization/*physiology
MH  - Adenosine Triphosphate/metabolism
MH  - Aerobiosis
MH  - *Altitude
MH  - Animals
MH  - Blood Glucose/metabolism
MH  - Calorimetry, Indirect
MH  - Dietary Sucrose/*metabolism
MH  - Female
MH  - Glucose/*metabolism
MH  - Glycogen/metabolism
MH  - Hypoxia/metabolism
MH  - Kinetics
MH  - Muscle, Skeletal/metabolism
MH  - Oxygen/physiology
MH  - Physical Exertion/*physiology
MH  - Rats
MH  - Rats, Wistar
PMC - PMC21501
EDAT- 1998/08/26 00:00
MHDA- 1998/08/26 00:01
PMCR- 1999/02/18
CRDT- 1998/08/26 00:00
PHST- 1998/08/26 00:00 [pubmed]
PHST- 1998/08/26 00:01 [medline]
PHST- 1998/08/26 00:00 [entrez]
PHST- 1999/02/18 00:00 [pmc-release]
AID - 2164 [pii]
AID - 10.1073/pnas.95.17.10288 [doi]
PST - ppublish
SO  - Proc Natl Acad Sci U S A. 1998 Aug 18;95(17):10288-93. doi: 
      10.1073/pnas.95.17.10288.