title: Effect of graded leg cycling on postischaemic forearm blood flow in healthy subjects.
abstract: This study assessed in healthy subjects, the effect of leg cycling on the forearm vascular responses to ischaemia to confirm previous results showing that exercise-induced sympathetic activation during leg cycling reduced postischaemic forearm hyperaemia. Seven young healthy subjects performed two bouts of cycling exercises at 50% and 80% of their maximal aerobic capacity (Ex(50), Ex(80) respectively) during which forearm arterial blood flow was successively occluded for 40, 90 and 180 s. Control forearm blood flow (FBF) and postischaemic forearm blood flow (pi-FBF) measured at the release of arterial occlusions were assessed using plethysmography. Digital arterial pressure was continuously monitored allowing calculation of control and postischaemic forearm conductance (FC and pi-FC respectively). At rest, pi-FBF increased with the duration of ischaemia (5 +/- 1, 19 +/- 3, 29 +/- 3, 31 +/- 4 ml min(-1) 100 ml(-1) after 0, 40, 90 and 180 s of ischaemia respectively). During Ex(50), FBF and pi-FBF did not change significantly although pi-FC was significantly reduced (Deltapi-FC = -39%, -33%, -27% for 40, 90, 180 s of ischaemia respectively). During Ex(80), there was a further dramatic decrease in pi-FC (-53%, -66%, -62% from rest) and pi-FBF were largely blunted (13 +/- 4 versus 19 +/- 3, 14 +/- 4 versus 29 +/- 3, 17 +/- 5 versus 31 +/- 4 ml min(-1) 100 ml(-1)). These results demonstrated that forearm responses to ischaemia depended on leg activities. It was suggested that exercise-induced sympathetic activation may have interfered on local vasodilatation because of ischaemia.
authors.affiliation: Physiology and Physiopathology of Exercise and Handicap Research unit, Jean Monnet University, Saint Etienne, France. marc.charles@univ-st-etienne.fr
authors.forename: Marc
authors.initials: M
authors.lastname: Charles
authors.forename: Vincent
authors.initials: V
authors.lastname: Pichot
authors.forename: Virginie
authors.initials: V
authors.lastname: Dauphinot
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Barthelemy
authors.forename: Christian
authors.initials: C
authors.lastname: Denis
authors.forename: Frédéric
authors.initials: F
authors.lastname: Roche
authors.forename: Frédéric
authors.initials: F
authors.lastname: Costes
mesh_terms: D000328:Adult; D001642:Bicycling; D001794:Blood Pressure; D015444:Exercise; D005542:Forearm / Q000098:blood supply*; D006339:Heart Rate; D006801:Humans; D006940:Hyperemia / Q000378:metabolism / Q000503:physiopathology*; D007511:Ischemia / Q000378:metabolism / Q000503:physiopathology*; D007866:Leg; D008297:Male; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000378:metabolism*; D010101:Oxygen Consumption; D010865:Pilot Projects; D010991:Plethysmography; D012123:Pulmonary Ventilation; D012016:Reference Values; D012039:Regional Blood Flow; D013564:Sympathetic Nervous System / Q000503:physiopathology; D013997:Time Factors; D014664:Vasodilation