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Matching of blood flow to metabolic rate during recovery from moderate exercise in humans
Author(s) -
Harper Allison J.,
Ferreira Leonardo F.,
Lutjemeier Barbara J.,
Townsend Dana K.,
Barstow Thomas J.
Publication year - 2008
Publication title -
experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0958-0670
DOI - 10.1113/expphysiol.2008.042895
Subject(s) - blood flow , cardiology , myoglobin , medicine , hemodynamics , rectus femoris muscle , exercise physiology , chemistry , physical medicine and rehabilitation , biochemistry , electromyography
It is unclear whether measurement of limb or conduit artery blood flow during recovery from exercise provides an accurate representation of flow to the muscle capillaries where gas exchange occurs. To investigate this, we: (a) examined the kinetic responses of femoral artery blood flow (), estimated muscle capillary blood flow () and estimated muscle oxygen uptake () following cessation of exercise; and (b) compared these responses to verify the adequacy of O 2 delivery during recovery. Pulmonary () was measured breath by breath, was measured using Doppler ultrasonography, and deoxy‐haemoglobin/myoglobin (deoxy‐[Hb/Mb]) was estimated by near‐infrared spectroscopy over the rectus femoris in nine healthy subjects during a series of transitions from moderate knee‐extension exercise to rest. The time course of was estimated by rearranging the Fick equation [i.e. ], using the primary component of to represent and deoxy‐[Hb/Mb] as a surrogate for arteriovenous O 2 difference. There were no significant differences among the overall kinetics of (τ, 31.4 ± 8.2 s), [mean response time (MRT), 34.5 ± 20.4 s] and (MRT, 31.7 ± 14.7 s). The kinetics were also significantly correlated ( P < 0.05) with those of both and . Both and appear to be coupled with during recovery from moderate knee‐extension exercise, such that extraction falls (thus cellular energetic state is not further compromised) throughout recovery.