Abstract
The work of breathing (W(B)), and thus the energy requirement of the respiratory muscles, is increased any time minute ventilation (V̇E) is elevated, by either exercise or voluntary hyperventilation. Respiratory muscle O2 consumption (V̇RM(O2)) in humans has generally been estimated by having subjects breathe at a level comparable to that during exercise while the change in O2 consumption (V̇O2) is measured. The difference between V̇O2 at rest and during hyperventilation is attributed to the respiratory muscles and is assumed to be similar to V̇RM(O2) during exercise at the same V̇E. However, it has been suggested that W(B) differs between exercise and hyperventilation and that W(B) during exercise is lower than during hyperventilation at the same V̇E. In this study we measured W(B) during exercise and hyperventilation and from these measurements estimated V̇RM(O2). W(B), V̇E, and V̇O2 were measured in five male subjects during rest and during exercise or hyperventilation at levels of V̇E ranging from 30 to 130 l/min. V̇E/W(B) relationship was determined for both hyperventilation and exercise. Multiple regression analysis showed that the shape of the two curves was different (P < 0.0001), with W(B) at high levels of V̇E being ≤25% higher in hyperventilation than in exercise. In a second study in which frequency, tidal volume, and duty cycle were controlled as well as V̇E, there was no difference in W(B) between exercise and hyperventilation. V̇O2 was significantly correlated with W(B), and the estimated V̇RM(O2) did not increase as a fraction of total V̇O2 as exercise intensity rose. From these results we suggest that when carefully controlled for both pattern and V̇E, hyperventilation can be used to mimic exercise and to estimate the metabolic cost of breathing. However, if only V̇E is controlled, it is necessary to measure W(B) to estimate the energy used by the respiratory muscles.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 793-798 |
| Number of pages | 6 |
| Journal | Journal of Applied Physiology |
| Volume | 74 |
| Issue number | 2 |
| State | Published - 1993 |
| Externally published | Yes |
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Keywords
- energetics
- work of breathing
ASJC Scopus subject areas
- Endocrinology
- Physiology
- Orthopedics and Sports Medicine
- Physical Therapy, Sports Therapy and Rehabilitation
Cite this
Ventilatory work and oxygen consumption during exercise and hyperventilation. / Coast, Richard J; Rasmussen, S. A.; Krause, K. M.; O'Kroy, J. A.; Loy, R. A.; Rhodes, J.
In: Journal of Applied Physiology, Vol. 74, No. 2, 1993, p. 793-798.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Ventilatory work and oxygen consumption during exercise and hyperventilation
AU - Coast, Richard J
AU - Rasmussen, S. A.
AU - Krause, K. M.
AU - O'Kroy, J. A.
AU - Loy, R. A.
AU - Rhodes, J.
PY - 1993
Y1 - 1993
N2 - The work of breathing (W(B)), and thus the energy requirement of the respiratory muscles, is increased any time minute ventilation (V̇E) is elevated, by either exercise or voluntary hyperventilation. Respiratory muscle O2 consumption (V̇RM(O2)) in humans has generally been estimated by having subjects breathe at a level comparable to that during exercise while the change in O2 consumption (V̇O2) is measured. The difference between V̇O2 at rest and during hyperventilation is attributed to the respiratory muscles and is assumed to be similar to V̇RM(O2) during exercise at the same V̇E. However, it has been suggested that W(B) differs between exercise and hyperventilation and that W(B) during exercise is lower than during hyperventilation at the same V̇E. In this study we measured W(B) during exercise and hyperventilation and from these measurements estimated V̇RM(O2). W(B), V̇E, and V̇O2 were measured in five male subjects during rest and during exercise or hyperventilation at levels of V̇E ranging from 30 to 130 l/min. V̇E/W(B) relationship was determined for both hyperventilation and exercise. Multiple regression analysis showed that the shape of the two curves was different (P < 0.0001), with W(B) at high levels of V̇E being ≤25% higher in hyperventilation than in exercise. In a second study in which frequency, tidal volume, and duty cycle were controlled as well as V̇E, there was no difference in W(B) between exercise and hyperventilation. V̇O2 was significantly correlated with W(B), and the estimated V̇RM(O2) did not increase as a fraction of total V̇O2 as exercise intensity rose. From these results we suggest that when carefully controlled for both pattern and V̇E, hyperventilation can be used to mimic exercise and to estimate the metabolic cost of breathing. However, if only V̇E is controlled, it is necessary to measure W(B) to estimate the energy used by the respiratory muscles.
AB - The work of breathing (W(B)), and thus the energy requirement of the respiratory muscles, is increased any time minute ventilation (V̇E) is elevated, by either exercise or voluntary hyperventilation. Respiratory muscle O2 consumption (V̇RM(O2)) in humans has generally been estimated by having subjects breathe at a level comparable to that during exercise while the change in O2 consumption (V̇O2) is measured. The difference between V̇O2 at rest and during hyperventilation is attributed to the respiratory muscles and is assumed to be similar to V̇RM(O2) during exercise at the same V̇E. However, it has been suggested that W(B) differs between exercise and hyperventilation and that W(B) during exercise is lower than during hyperventilation at the same V̇E. In this study we measured W(B) during exercise and hyperventilation and from these measurements estimated V̇RM(O2). W(B), V̇E, and V̇O2 were measured in five male subjects during rest and during exercise or hyperventilation at levels of V̇E ranging from 30 to 130 l/min. V̇E/W(B) relationship was determined for both hyperventilation and exercise. Multiple regression analysis showed that the shape of the two curves was different (P < 0.0001), with W(B) at high levels of V̇E being ≤25% higher in hyperventilation than in exercise. In a second study in which frequency, tidal volume, and duty cycle were controlled as well as V̇E, there was no difference in W(B) between exercise and hyperventilation. V̇O2 was significantly correlated with W(B), and the estimated V̇RM(O2) did not increase as a fraction of total V̇O2 as exercise intensity rose. From these results we suggest that when carefully controlled for both pattern and V̇E, hyperventilation can be used to mimic exercise and to estimate the metabolic cost of breathing. However, if only V̇E is controlled, it is necessary to measure W(B) to estimate the energy used by the respiratory muscles.
KW - energetics
KW - work of breathing
UR - http://www.scopus.com/inward/record.url?scp=0027476988&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0027476988&partnerID=8YFLogxK
M3 - Article
C2 - 8458797
AN - SCOPUS:0027476988
VL - 74
SP - 793
EP - 798
JO - Journal of Applied Physiology Respiratory Environmental and Exercise Physiology
JF - Journal of Applied Physiology Respiratory Environmental and Exercise Physiology
SN - 8750-7587
IS - 2
ER -