Gokyo Khumbu/Ama Dablam Trek 2012: effects of physical training and high-altitude exposure on oxidative metabolism, muscle composition, and metabolic cost of walking in women.
OBJECTIVE
We investigated the effects of moderate-intensity training at low and high altitude on VO2 and QaO2 kinetics and on myosin heavy-chain expression (MyHC) in seven women (36.3 yy ± 7.1; 65.8 kg ± 11.7; 165 cm ± 8) who participated in two 12- to 14-day trekking expeditions at low (598 m) and high altitude (4132 m) separated by 4 months of recovery.


METHODS
Breath-by-breath VO2 and beat-by-beat QaO2 at the onset of moderate-intensity cycling exercise and energy cost of walking (Cw) were assessed before and after trekking. MyHC expression of vastus lateralis was evaluated before and after low-altitude and after high-altitude trekking; muscle fiber high-resolution respirography was performed at the beginning of the study and after high-altitude trekking.


RESULTS
Mean response time of VO2 kinetics was faster (P = 0.002 and P = 0.001) and oxygen deficit was smaller (P = 0.001 and P = 0.0004) after low- and high-altitude trekking, whereas ˙ QaO2 kinetics and Cw did not change. Percentages of slow and fast isoforms of MyHC and mitochondrial mass were not affected by low- and high-altitude training. After training altitude, muscle fiber ADP-stimulated mitochondrial respiration was decreased as compared with the control condition (P = 0.016), whereas leak respiration was increased (P = 0.031), leading to a significant increase in the respiratory control ratio (P = 0.016).


CONCLUSIONS
Although training did not significantly modify muscle phenotype, it induced beneficial adaptations of the oxygen transport-utilization systems witnessed by faster VO2 kinetics at exercise onset.
Department of Neurological and Movement Sciences, University of Verona, Verona, Italy.
E
E
Tam
Department of Neurological and Movement Sciences, University of Verona, Verona, Italy.
P
P
Bruseghini
Department of Neurological and Movement Sciences, University of Verona, Verona, Italy.
E
E
Calabria
Department of Neurological and Movement Sciences, University of Verona, Verona, Italy.
L
L
Dal Sacco
Department of Neurosciences, Imaging and Clinical Sciences, University of Chieti-Pescara, Chieti, Italy.
C
C
Doria
Department of Medical and Biological Sciences, University of Udine, Udine, Italy.
B
B
Grassi
Department of Neurosciences, Imaging and Clinical Sciences, University of Chieti-Pescara, Chieti, Italy.
T
T
Pietrangelo
Department of Neurological and Movement Sciences, University of Verona, Verona, Italy.
S
S
Pogliaghi
Department of Biomedical Sciences, University of Padua, Padua, Italy.
C
C
Reggiani
Department of Medical and Biological Sciences, University of Udine, Udine, Italy.
D
D
Salvadego
Department of Neurological and Movement Sciences, University of Verona, Verona, Italy.|CeRiSM, Rovereto, TN, Italy.
F
F
Schena
Department of Biomedical Sciences, University of Padua, Padua, Italy.
L
L
Toniolo
Department of Neurosciences, Imaging and Clinical Sciences, University of Chieti-Pescara, Chieti, Italy.
V
V
Verratti
CeRiSM, Rovereto, TN, Italy.|Department of Biomedical Sciences for Health, University of Milano, Milan, Italy.
G
G
Vernillo
Department of Neurological and Movement Sciences, University of Verona, Verona, Italy. carlo.capelli@univr.it.|CeRiSM, Rovereto, TN, Italy. carlo.capelli@univr.it.|Department of Physical Performances, Norwegian School of Sport Sciences, Sognsveien 220, 0806, Oslo, Norway. carlo.capelli@univr.it.
Carlo
http://orcid.org/0000-0002-3278-1337
C
Capelli
D000328:Adult; D000531:Altitude; D005260:Female; D006801:Humans; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*; D018995:Myosin Heavy Chains / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D010101:Oxygen Consumption / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology*; D052097:Quadriceps Muscle / Q000378:metabolism; D016138:Walking
D018995:Myosin Heavy Chains; D010100:Oxygen
Aerobic metabolism; Chronic hypoxia; Energy cost of walking; Exercise training; Women