Exercise ventilation correlates positively with ventilatory chemoresponsiveness

Abstract

To determine the relationship of ventilatory responsiveness to hypoxia and hypercapnia to exercise hyperpnea, these responses and steady-state exercise ventilation (VE) were measured in 16 athletes during light (1/3 VO2 max) and heavy (2/3 VO2 max) exercise. Both the hypoxic and hypercapnic ventilatory responses correlated positively with VE per unit metabolic rate (VE/VCO2) at both exercise levels (P less than 0.05). The contribution of the hypoxic response to normoxic exercise VE was quantified by comparing VE in normoxia to VE during a brief (1 min) exposure to high O2 (PAO2 = 200 Torr). High O2 reduced normoxic exercise VE by a mean of 20% at either exercise intensity. Among individuals this reduction was directly dependent upon the intensity of the hypoxic response, and ranged from 7 to 42% of normoxic VE. After the variable reduction of normoxic VE by hyperoxia, all correlations of ventilatory response with exercise VE were lost except for the correlation of hypercapnic response with heavy exercise VE/VCO2. These findings indicate that the extent of VE in light or heavy exercise is modified by the strength of the hypoxic ventilatory response, and that the hypercapnic response independently correlates with VE during heavy exercise.

Increased Peripheral Chemoreceptors Sensitivity and Exercise Ventilation in Heart Transplant Recipients

“…The group-by-time interaction was tested. Because the hypoxic ventilatory response correlates to the body surface area, 2,20,21 changes in ventilation in response to hypoxia were normalized for body surface area and related to the ventilatory response to exercise (characterized by the regression slope relating ventilation to CO 2 output during exercise, V E/V CO 2 slope) through linear regression analysis. 11 Responses to hypercapnia were compared by a Mann-Whitney test.…”

“…1 Peripheral chemoreceptors also play an important modulatory role in the regulation of ventilation during exercise. [2][3][4][5] This is evidenced by the observation that breathing oxygen decreases ventilation and increases arterial carbon dioxide to a greater extent during exercise than at rest. 6,7 Central chemoreceptors are located in the brain stem and respond primarily to hypercapnia.…”

“…9 In normal subjects and athletes, there is a positive relation between V E and the rate of CO 2 production (V CO 2 ) during exercise and central chemoreceptor sensitivity at rest. 2,5,10 Heart failure is accompanied by increased peripheral and central chemosensitivity, 11,12 which correlates with an in-…”

High ventilatory response to hypoxia observed in obese judo athletes.

“…In addition to the obesity factor described above, numerous other factors Vol.32, No.4, 1982 Y. OHYABU, A. YOSHIDA, F. HAYASHI, N. SATO, and Y. HONDA have been reported to affect hypoxic sensitivity : altitude exposure (MILLEDGE and LAHIRI, 1967;WEIL et al, 1971a), athleticism (BYRNE-QUINN et al, 1971;MARTIN et al, 1978), hyperthermia (NATALINO, 1977), mixed venous PCO2, level (REBUCK and WOODLEY, 1975), malnutrition (DAEKEL, 1976), aging (KRONENBERG and DRAGE, 1973, familial or genetic factor (COLLINS et al, 1978 ;KAWAKAMI et al, 1981a ;KAWAKAMI et al, 1981b), congenital cyanotic heart disease (SORENSEN and SEVERINGHAUS, 1968 ;BLESA et al, 1977), various drugs, anesthesia or sedation (HIRSHMAN et al, 1975a ;HIRSHMAN et al, 1975b ;YACOUB et al, 1976;HIRSHMAN et al, 1977;KNILL and GELB, 1978;LAKSHMINARAYAN et al, 1978 ;SANDERS et al, 1980), and alveolar hypoventilation syndromes (SHANNON and KELLY, 1977 ;BRADLEY et al, 1979 ;SCHIFFMAN et al, 1980;BERMAN et al, 1981 ;HUNT et al, 1981). None of the above factors, however, seems to satisfactorily explain the results obtained in the present study.…”

Respiratory Compensation Point during Incremental Exercise as Related to Hypoxic Ventilatory Chemosensitivity and Lactate Increase in Man.

“…Peripheral chemosensitivity was assessed by hypoxic ventilatory responsiveness (HVR) and central chemosensitivity by hypercapnic ventilatory responsiveness (HCVR), both at rest. Since it has been reported that HVR [10][11][12] and HCVR [13] increase with increasing exercise intensity, and that the exercise estimates of HVR depend on the resting estimates of HVR [11,12,14], the individual differences in exercise estimates of chemosensitivities at varying work rates were assumed to be predicted from those in the resting estimates.…”