Abstract
Introduction:
Incremental exercise test protocols combined with measurements of oxygen uptake (VO2) and carbon dioxide (VCO2) production are widely used for performance testing and indirect calorimetry. Depending on testing equipment, VO2 and VCO2 are often sampled or averaged over 0.5 min or up to 1.0 min periods.
The onset kinetics of the VO2 and VCO2 depends on exercise intensity (Ozyener et al. 2001, Bell et al. 1999). Therefore, depending on exercise intensity and sampling or averaging period, different VO2 results and a corresponding effect on VCO2 can be expected. We tested whether and how sampling or averaging of respiratory data over 0.5 min or 1.0 min affect assumptions and results of indirect calorimetry in an incremental exercise test.
Methods: 21 healthy male subjects (age: 26.3 ± 6.0 yrs, height: 179.4 ± 8.1 cm, body mass: 74.9 ± 12.5 kg) completed an incremental load cycling test to exhaustion at 50 rpm. Starting with 1 W.kg-1 body mass, power output was increased by 0.5 W.kg-1 body mass every two minutes.
Three intensity domains were investigated: light 20-39 %, moderate 40-59 %, and heavy 60-85 % (ACSM Guidelines, 2000). VO2 and VCO2 data were averaged for the last 0.5 and 1.0 min of every stage of the incremental exercise test. All data are presented as Mean ± SD and tested using a repeated measures ANOVA model with averaging period as within factor and exercise intensity domain as between factor, Tukey post hoc and paired t-test. Significance was set at p<0.05.
Results:
VO2 was higher when averaged for 0.5 than 1.0 min at heavy (p < 0.05) but not at light, or moderate intensity. VCO2 was higher when averaged for 0.5 than 1.0 min at all intensity domains (p < 0.05). Consequently carbohydrate combustion rate was also significantly higher for 0.5 than 1.0 min averaging at all intensities (p<0.05).
Conclusion:
Increasing the period of averaging from 0.5 to 1.0 min resulted in an underestimation of the metabolic rate at moderate and heavy exercise intensity in the magnitude of approx. 0.1 and 0.6 %, respectively, which may be practically irrelevant. However, the latter is combined with a significant underestimation of the reliance on carbohydrate combustion of approx. 9.2 % in the light, approx. 4.9 % in the moderate, and 3.8 % in the heavy intensity domain.
Incremental exercise test protocols combined with measurements of oxygen uptake (VO2) and carbon dioxide (VCO2) production are widely used for performance testing and indirect calorimetry. Depending on testing equipment, VO2 and VCO2 are often sampled or averaged over 0.5 min or up to 1.0 min periods.
The onset kinetics of the VO2 and VCO2 depends on exercise intensity (Ozyener et al. 2001, Bell et al. 1999). Therefore, depending on exercise intensity and sampling or averaging period, different VO2 results and a corresponding effect on VCO2 can be expected. We tested whether and how sampling or averaging of respiratory data over 0.5 min or 1.0 min affect assumptions and results of indirect calorimetry in an incremental exercise test.
Methods: 21 healthy male subjects (age: 26.3 ± 6.0 yrs, height: 179.4 ± 8.1 cm, body mass: 74.9 ± 12.5 kg) completed an incremental load cycling test to exhaustion at 50 rpm. Starting with 1 W.kg-1 body mass, power output was increased by 0.5 W.kg-1 body mass every two minutes.
Three intensity domains were investigated: light 20-39 %, moderate 40-59 %, and heavy 60-85 % (ACSM Guidelines, 2000). VO2 and VCO2 data were averaged for the last 0.5 and 1.0 min of every stage of the incremental exercise test. All data are presented as Mean ± SD and tested using a repeated measures ANOVA model with averaging period as within factor and exercise intensity domain as between factor, Tukey post hoc and paired t-test. Significance was set at p<0.05.
Results:
VO2 was higher when averaged for 0.5 than 1.0 min at heavy (p < 0.05) but not at light, or moderate intensity. VCO2 was higher when averaged for 0.5 than 1.0 min at all intensity domains (p < 0.05). Consequently carbohydrate combustion rate was also significantly higher for 0.5 than 1.0 min averaging at all intensities (p<0.05).
Conclusion:
Increasing the period of averaging from 0.5 to 1.0 min resulted in an underestimation of the metabolic rate at moderate and heavy exercise intensity in the magnitude of approx. 0.1 and 0.6 %, respectively, which may be practically irrelevant. However, the latter is combined with a significant underestimation of the reliance on carbohydrate combustion of approx. 9.2 % in the light, approx. 4.9 % in the moderate, and 3.8 % in the heavy intensity domain.
| Original language | English |
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| Pages | 213-214 |
| Number of pages | 2 |
| Publication status | Published - Jul 2006 |
| Event | 11th Annual Congress of the European College of Sport Science (ECSS), 5-8th July 2006, Lausanne, Switzerland. - Lausanne, Lausannes, Switzerland Duration: 5 Jul 2006 → 8 Jul 2006 |
Conference
| Conference | 11th Annual Congress of the European College of Sport Science (ECSS), 5-8th July 2006, Lausanne, Switzerland. |
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| Country/Territory | Switzerland |
| City | Lausannes |
| Period | 5/07/06 → 8/07/06 |