The metabolic and ventilatory response to exercise in Tibetans born at low altitude.

Details

Serval ID
serval:BIB_764B3F92D214
Type
Article: article from journal or magazin.
Collection
Publications
Title
The metabolic and ventilatory response to exercise in Tibetans born at low altitude.
Journal
Respiration Physiology
Author(s)
Kayser B., Marconi C., Amatya T., Basnyat B., Colombini A., Broers B., Cerretelli P.
ISSN
0034-5687 (Print)
ISSN-L
0034-5687
Publication state
Published
Issued date
1994
Volume
98
Number
1
Pages
15-26
Language
english
Abstract
The exercise response of 20 Tibetans (T) born and living in Kathmandu, Nepal (1300 m) was compared to that of 21 age- and sex-matched local lowlanders. The subjects carried out an incremental exercise protocol on a bicycle ergometer (30 watt steps every 4 min) until exhaustion. The kinetics of readjustment of VO2 measured as half time (t-on) upon a 90 watt constant load exercise was also determined. Breath-by-breath gas exchange, heart rate (HR) and blood lactate concentration ([La]) were measured at rest, at the end of each load and during recovery. The slope of the straight line relating VO2 to work load was 10.8 ml.watt-1 in both groups which corresponds to a mechanical efficiency of 0.26 (assuming a RQ of 0.89 and an energy equivalent of 20.9 kJ.L-1 O2). At submaximal loads T were characterized by higher VE (P < 0.05), VE.VO2(-1) (P < 0.01) and VCO2 levels (P < 0.001) than N. The found higher VE in T, resulting from a lower tidal volume coupled to a higher respiratory frequency, led to higher PETO2 (P < 0.001) and SaO2 (P < 0.001) at all work levels. Absolute VO2max in the two investigated groups were 1977 +/- 72 (T) and 2095 +/- 80 (N) ml.min-1 (NS). Specific (i.e. per kg body weight) VO2max were identical (37.0 +/- 1.1 [T] vs. 36.7 +/- 1.1 ml.kg-1.min-1 [N]). [La]max were 11.4 +/- 0.4 (T) vs. 12.3 +/- 0.4 (N) mM (NS). [La] accumulation in blood as a function of workload and its rate of disappearance during recovery were similar. t-on at 90 watt was 30.7 +/- 2.4 sec in T and 28.9 +/- 2.3 sec in N (NS). The corresponding average contracted O2 deficit were 971 ml for T and 994 ml for N (NS). In conclusion, Tibetans born at low altitude do not seem to differ from lowlanders with regard to their metabolic response whereas their ventilatory response to exercise is greater.
Keywords
Adolescent, Adult, Aerobiosis/physiology, Altitude, Body Composition/physiology, Body Height/physiology, Body Weight/physiology, Exercise/physiology, Exercise Test, Female, Humans, Lactates/blood, Lactic Acid, Male, Metabolism/genetics, Metabolism/physiology, Nepal, Oxygen Consumption/physiology, Pulmonary Gas Exchange/physiology, Respiratory Mechanics/physiology, Tibet/ethnology
Pubmed
Web of science
Create date
19/09/2013 12:48
Last modification date
20/08/2019 15:33
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