Respiratory compensation point during incremental exercise as related to hypoxic ventilatory chemosensitivity and lactate increase in man
| Autor: | Nariko Takano |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Adult
Male medicine.medical_specialty Physiology Physical Exertion Peripheral chemoreceptors Hypoxic ventilatory response Respiratory compensation Incremental exercise Hypercapnia Internal medicine medicine Humans Lactic Acid Hypoxia Acidosis Body surface area Carotid Body business.industry Pulmonary Gas Exchange General Medicine Carbon Dioxide Oxygen Endocrinology medicine.anatomical_structure Cardiology Linear Models Carotid body Acidosis Lactic Female medicine.symptom business Ventilatory threshold Pulmonary Ventilation |
| Zdroj: | The Japanese journal of physiology. 50(4) |
| ISSN: | 0021-521X |
| Popis: | The pulmonary ventilation-O2 uptake (VE-VO2) relationship during incremental exercise has two inflection points: one at a lower VO2, termed the ventilatory threshold (VT); and another at a higher VO2, the respiratory compensation point (RCP). The individuality of RCP was studied in relation to those of the chemosensitivities of the central and peripheral chemoreceptors, which were assessed by resting estimates of hypercapnic ventilatory response (HCVR) and hypoxic ventilatory response (HVR), respectively, and the rate of lactic acid increase during exercise, which was estimated as a slope difference (delta slope) between a lower slope of VCO2-VO2 relationship (VCO2:CO2 output) obtained at work rates below VT and a higher slope at work rates between VT and RCP. Twenty-two male and sixteen female subjects underwent a 1 min incremental exercise test until exhaustion, in which VT, RCP and delta slope were determined. All measures were normalized for body surface area. In the males, the individual difference in RCP was inversely correlated with those of HVR and delta slope (p < 0.05), and in the females, similar tendencies persisted, while the correlation did not reach statistically significant levels (0.05 < p < 0.1). There was no significant correlation between RCP and HCVR in either sex. A multiple linear regression analysis showed that 40 to 50% of the variance of RCP was accounted for by those of HVR and delta slope, both of which were related linearly and additively to RCP, this relation being manifested in the males but not in the females without consideration of the menstrual cycle. These results suggest that the individuality of RCP depends partly on the chemosensitivity of the carotid bodies and the rate of lactic acid increase during incremental exercise. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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