Kinetics of VCO2 during increnental exercise.
- VernacularTitle:漸増運動負荷時のＶｃｏ２の動態
- Author:
TOKUO YANO
;
KATSUMI ASANO
;
TAKEO NOMURA
;
AKIRA MATSUZAKA
;
KOHJI HIRAKOBA
- Publication Type:Journal Article
- Keywords:
steady state excercise;
incremental exercise;
CO2store;
CO2excess
- From:Japanese Journal of Physical Fitness and Sports Medicine
1984;33(4):201-210
- CountryJapan
- Language:Japanese
-
Abstract:
The purpose of this study was to investigate the kinetics of Vco2during incremental exercise. The subjects were 7 males, age 21-28 years, exercised at two steady state work loads (540 kpm/min, 810 kpm/min) and incremental work load which was increased stepwise by every 1 min from 180 kpm/min to exhaustion. The Vo2and Vco2during steady state exercise (4 to 5 min) were determined by the Douglas bag method and arterialized blood samples were taken for lactate (LA) analysis and blood gas analysis. The Vo2, Vco2, and blood lactate were also determined throughout the incremental exercise. At exhaustion, mixed venous Pco2 (PVco2) was determined by the CO2rebreathing method.
1) The Vco2values at rest and during steady state exercise were linearly related to the Vo2values. When the regression line was compared with Vco2during the incremental exercise on the same Vo2, the Vco2during the incremental exercise below the anaerobic threshold showed lower values.
2) The total sum of the difference in Vco2between steady state and incremental exercise was defined as CO2store. The calculated CO2store and CO2store per body weight were significantly related to PVco2at exhaustion in incremental exercise, respectively (r=0.954, r=0.954) .
3) At work load below the anaerobic threshold, Vco2was linearly related to Vo2. If the Vco2above the anaerobic threshold is estimated from Vo2using the regression line obtained at work load below the anaerobic threshold, the estimated Vco2will be lower than the measured Vco2. The total sum of the difference in the Vco2was defined as CO2excess. The CO2excess and the CO2excess per body weight were significantly related to ΔLAmax (the difference between LA at 3rd min after exhastion and LA at exercise below the anaerobic threshold), respectively (r=0.870, r=0.930) .
4) HCO3-calculated from blood gases (pH and Pco2) was significantly related to LA (r=-0.902) . The increase of 1 mM/1 in LA was corresponding to the decrease of 0.843 mEq/l in HCO3-.
5) From these results, it appeared that the expired Vco2during the incremental exercise consisted of the stored Vco2, the exceeded Vco2, and the produced Vco2 (Vco2metabolically produced from Vo2) .
