Abstract
To quantitate the O 2 cost of maximal exercise hyperpnea, we required eight healthy adult subjects to mimic, at rest, the important mechanical components of submaximal and maximal exercise hyperpnea. Expired minute ventilation (V̇E), transpulmonary and trans-diaphragmatic (Pdi) pressures, and end-expiratory lung volume (EELV) were measured during exercise at 70 and 100% of maximal O 2 uptake. At rest, subjects were given visual feedback of their exercise transpulmonary pressure-tidal volume loop (Ẇ(v)), breathing frequency, and EELV, which they mimicked repeatedly for 5 min per trial over several trials, while hypocapnia was prevented. The change in total body O 2 uptake (V̇O 2) was measured and presumed to represent the O 2 cost of the hyperpnea. In 61 mimicking trials with V̇E of 115-167 l/min and Ẇ(v) of 124-544 J/min, V̇E, Ẇ(v), duty cycle of the breath, and expiratory gastric pressure (Pga) integrated with respect to time (∫Pga · dt/min) were not different from those observed during maximum exercise. ∫Pdi · dt/min was 14% less and EELV was 6% greater during maximum exercise than during mimicking. The O 2 cost measurements within a subject were reproducible over 3-12 trials (coefficient of variation ±10%, range 5-16%). The O 2 costs of hyperpnea correlated highly and positively with V̇E and Ẇ(v) and less, but significantly, with ∫Pdi · dt and ∫Pga · dt. The O 2 cost of V̇E rose out of proportion to the increasing hyperpnea, so that between 70 and 100% of maximal V̇O 2 ΔV̇O 2/ΔV̇E increased 40-60% (1.8 ± 0.2 to 2.9 ± 0.1 ml O 2/l V̇E) as V̇E doubled. We believe that these data provide a realistic conservative estimate of the actual cost of exercise hyperpnea over a broad range of ventilatory outputs during moderately heavy-to-maximum exercise in healthy human subjects.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1810-1817 |
| Number of pages | 8 |
| Journal | Journal of Applied Physiology |
| Volume | 72 |
| Issue number | 5 |
| State | Published - 1992 |
| Externally published | Yes |
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Keywords
- end-expiratory lung volume
- expiratory muscles
- inspiratory muscles
- ventilatory work
ASJC Scopus subject areas
- Endocrinology
- Physiology
- Orthopedics and Sports Medicine
- Physical Therapy, Sports Therapy and Rehabilitation
Cite this
Oxygen cost of exercise hyperpnea : Measurement. / Aaron, E. A.; Johnson, Bruce David; Seow, C. K.; Dempsey, J. A.
In: Journal of Applied Physiology, Vol. 72, No. 5, 1992, p. 1810-1817.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Oxygen cost of exercise hyperpnea
T2 - Measurement
AU - Aaron, E. A.
AU - Johnson, Bruce David
AU - Seow, C. K.
AU - Dempsey, J. A.
PY - 1992
Y1 - 1992
N2 - To quantitate the O 2 cost of maximal exercise hyperpnea, we required eight healthy adult subjects to mimic, at rest, the important mechanical components of submaximal and maximal exercise hyperpnea. Expired minute ventilation (V̇E), transpulmonary and trans-diaphragmatic (Pdi) pressures, and end-expiratory lung volume (EELV) were measured during exercise at 70 and 100% of maximal O 2 uptake. At rest, subjects were given visual feedback of their exercise transpulmonary pressure-tidal volume loop (Ẇ(v)), breathing frequency, and EELV, which they mimicked repeatedly for 5 min per trial over several trials, while hypocapnia was prevented. The change in total body O 2 uptake (V̇O 2) was measured and presumed to represent the O 2 cost of the hyperpnea. In 61 mimicking trials with V̇E of 115-167 l/min and Ẇ(v) of 124-544 J/min, V̇E, Ẇ(v), duty cycle of the breath, and expiratory gastric pressure (Pga) integrated with respect to time (∫Pga · dt/min) were not different from those observed during maximum exercise. ∫Pdi · dt/min was 14% less and EELV was 6% greater during maximum exercise than during mimicking. The O 2 cost measurements within a subject were reproducible over 3-12 trials (coefficient of variation ±10%, range 5-16%). The O 2 costs of hyperpnea correlated highly and positively with V̇E and Ẇ(v) and less, but significantly, with ∫Pdi · dt and ∫Pga · dt. The O 2 cost of V̇E rose out of proportion to the increasing hyperpnea, so that between 70 and 100% of maximal V̇O 2 ΔV̇O 2/ΔV̇E increased 40-60% (1.8 ± 0.2 to 2.9 ± 0.1 ml O 2/l V̇E) as V̇E doubled. We believe that these data provide a realistic conservative estimate of the actual cost of exercise hyperpnea over a broad range of ventilatory outputs during moderately heavy-to-maximum exercise in healthy human subjects.
AB - To quantitate the O 2 cost of maximal exercise hyperpnea, we required eight healthy adult subjects to mimic, at rest, the important mechanical components of submaximal and maximal exercise hyperpnea. Expired minute ventilation (V̇E), transpulmonary and trans-diaphragmatic (Pdi) pressures, and end-expiratory lung volume (EELV) were measured during exercise at 70 and 100% of maximal O 2 uptake. At rest, subjects were given visual feedback of their exercise transpulmonary pressure-tidal volume loop (Ẇ(v)), breathing frequency, and EELV, which they mimicked repeatedly for 5 min per trial over several trials, while hypocapnia was prevented. The change in total body O 2 uptake (V̇O 2) was measured and presumed to represent the O 2 cost of the hyperpnea. In 61 mimicking trials with V̇E of 115-167 l/min and Ẇ(v) of 124-544 J/min, V̇E, Ẇ(v), duty cycle of the breath, and expiratory gastric pressure (Pga) integrated with respect to time (∫Pga · dt/min) were not different from those observed during maximum exercise. ∫Pdi · dt/min was 14% less and EELV was 6% greater during maximum exercise than during mimicking. The O 2 cost measurements within a subject were reproducible over 3-12 trials (coefficient of variation ±10%, range 5-16%). The O 2 costs of hyperpnea correlated highly and positively with V̇E and Ẇ(v) and less, but significantly, with ∫Pdi · dt and ∫Pga · dt. The O 2 cost of V̇E rose out of proportion to the increasing hyperpnea, so that between 70 and 100% of maximal V̇O 2 ΔV̇O 2/ΔV̇E increased 40-60% (1.8 ± 0.2 to 2.9 ± 0.1 ml O 2/l V̇E) as V̇E doubled. We believe that these data provide a realistic conservative estimate of the actual cost of exercise hyperpnea over a broad range of ventilatory outputs during moderately heavy-to-maximum exercise in healthy human subjects.
KW - end-expiratory lung volume
KW - expiratory muscles
KW - inspiratory muscles
KW - ventilatory work
UR - http://www.scopus.com/inward/record.url?scp=0026667009&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0026667009&partnerID=8YFLogxK
M3 - Article
VL - 72
SP - 1810
EP - 1817
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
SN - 8750-7587
IS - 5
ER -