title: Limb-specific training affects exercise hyperemia but not sympathetic vasoconstriction.
abstract: This study used cross-sectional and longitudinal training research designs to determine if (a) exercise hyperemia is enhanced in exercise-trained forearms and (b) sympathetic vasoconstriction of the trained forearm is attenuated (sympatholysis) during handgrip exercise. In the cross-sectional comparison, 10 rock climbers, 10 runners, 10 controls participated while the longitudinal training study examined vascular responsiveness in six untrained men before and after 6 weeks of handgrip training. Mean blood velocity, brachial artery diameter, heart rate, and systemic blood pressure were measured at rest, during a cold pressor test (CPT), dynamic handgrip exercise at 30% MVC with and without CPT, and during reactive hyperemia. During the resting CPT, forearm blood flow (FBF) decreased less (P < 0.05) in runners than in climbers, the decline being -6.30 + 30.05 and -34.3 + 20.54 during the last minute, respectively. During handgrip exercise, FBF and vascular conductance (VC) increased more (P < 0.05) in climbers than in runners and controls, the latter reaching 3.98 + 1.11, 2.22 + 0.88, and 2.75 + 1.06 ml min(-1) mmHg(-1), respectively. When a CPT was added during handgrip exercise, the reduction in FBF and VC was not different between the groups. Handgrip training increased (P < 0.05) forearm volume (5 + 3%) and MVC (25 + 29%), but did not affect FBF or VC during a CPT, with or without exercise. These data suggest that arm-trained athletes have greater exercise hyperemia. However, this training effect is not explained by sympatholysis and is not evident after 6 weeks of handgrip training in previously untrained subjects.
authors.affiliation: Department of Adolescent and Adult Education, Armstrong Atlantic State University, 11935 Abercorn Street, Savannah, GA 31419, USA. greg.wimer@armstrong.edu
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Wimer
authors.forename: James C
authors.initials: JC
authors.lastname: Baldi
mesh_terms: D000328:Adult; D062186:Arterial Pressure / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005542:Forearm / Q000098:blood supply* / Q000502:physiology; D006801:Humans; D006940:Hyperemia / Q000503:physiopathology*; D008297:Male; D012039:Regional Blood Flow / Q000502:physiology; D013564:Sympathetic Nervous System / Q000502:physiology; D014661:Vasoconstriction / Q000502:physiology*