title: Peripheral circulation.
abstract: Blood flow (BF) increases with increasing exercise intensity in skeletal, respiratory, and cardiac muscle. In humans during maximal exercise intensities, 85% to 90% of total cardiac output is distributed to skeletal and cardiac muscle. During exercise BF increases modestly and heterogeneously to brain and decreases in gastrointestinal, reproductive, and renal tissues and shows little to no change in skin. If the duration of exercise is sufficient to increase body/core temperature, skin BF is also increased in humans. Because blood pressure changes little during exercise, changes in distribution of BF with incremental exercise result from changes in vascular conductance. These changes in distribution of BF throughout the body contribute to decreases in mixed venous oxygen content, serve to supply adequate oxygen to the active skeletal muscles, and support metabolism of other tissues while maintaining homeostasis. This review discusses the response of the peripheral circulation of humans to acute and chronic dynamic exercise and mechanisms responsible for these responses. This is accomplished in the context of leading the reader on a tour through the peripheral circulation during dynamic exercise. During this tour, we consider what is known about how each vascular bed controls BF during exercise and how these control mechanisms are modified by chronic physical activity/exercise training. The tour ends by comparing responses of the systemic circulation to those of the pulmonary circulation relative to the effects of exercise on the regional distribution of BF and mechanisms responsible for control of resistance/conductance in the systemic and pulmonary circulations.
authors.affiliation: Department of Medical Pharmacology and Physiology, and the Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, USA. laughlinm@missouri.edu
authors.forename: M Harold
authors.initials: MH
authors.lastname: Laughlin
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Davis
authors.forename: Niels H
authors.initials: NH
authors.lastname: Secher
authors.forename: Johannes J
authors.initials: JJ
authors.lastname: van Lieshout
authors.forename: Arturo A
authors.initials: AA
authors.lastname: Arce-Esquivel
authors.forename: Grant H
authors.initials: GH
authors.lastname: Simmons
authors.forename: Shawn B
authors.initials: SB
authors.lastname: Bender
authors.forename: Jaume
authors.initials: J
authors.lastname: Padilla
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Bache
authors.forename: Daphne
authors.initials: D
authors.lastname: Merkus
authors.forename: Dirk J
authors.initials: DJ
authors.lastname: Duncker
mesh_terms: D001794:Blood Pressure / Q000502:physiology; D001842:Bone and Bones / Q000098:blood supply; D002302:Cardiac Output / Q000502:physiology; D003326:Coronary Circulation / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005835:Genitalia / Q000098:blood supply; D006801:Humans; D018482:Muscle, Skeletal / Q000098:blood supply; D010101:Oxygen Consumption / Q000502:physiology; D011652:Pulmonary Circulation / Q000502:physiology; D012039:Regional Blood Flow / Q000502:physiology*; D012079:Renal Circulation / Q000502:physiology; D013152:Splanchnic Circulation / Q000502:physiology