title: Remote ischemic preconditioning delays fatigue development during handgrip exercise.
abstract: Ischemic preconditioning (IPC) of one or two limbs improves performance of exercise that recruits the same limb(s). However, it is unclear whether IPC application to another limb than that in exercise is also effective and which mechanisms are involved. We investigated the effect of remote IPC (RIPC) on muscle fatigue, time to task failure, forearm hemodynamics, and deoxygenation during handgrip exercise. Thirteen men underwent RIPC in the lower limbs or a control intervention (CON), in random order, and then performed a constant load rhythmic handgrip protocol until task failure. Rates of contraction and relaxation (ΔForce/ΔTime) were used as indices of fatigue. Brachial artery blood flow and conductance, besides forearm microvascular deoxygenation, were assessed during exercise. RIPC attenuated the slowing of contraction and relaxation throughout exercise (P < 0.05 vs CON) and increased time to task failure by 11.2% (95% confidence interval: 0.7-21.7%, P <0.05 vs CON). There was no significant difference in blood flow, conductance, and deoxygenation between conditions throughout exercise (P > 0.05). In conclusion, RIPC applied to the lower limbs delayed the development of fatigue during handgrip exercise, prolonged time to task failure, but was not accompanied by changes in forearm hemodynamics and deoxygenation.
authors.affiliation: Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil.
authors.forename: T C
authors.initials: TC
authors.lastname: Barbosa
authors.affiliation: Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil.
authors.forename: A C
authors.initials: AC
authors.lastname: Machado
authors.affiliation: Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil.
authors.forename: I D
authors.initials: ID
authors.lastname: Braz
authors.affiliation: Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil.
authors.forename: I A
authors.initials: IA
authors.lastname: Fernandes
authors.affiliation: Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil.
authors.forename: L C
authors.initials: LC
authors.lastname: Vianna
authors.affiliation: Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil.
authors.forename: A C L
authors.initials: AC
authors.lastname: Nobrega
authors.affiliation: Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil.|Department of Physiology, Section of Exercise Physiology, Federal University of São Paulo, São Paulo, Brazil.
authors.forename: B M
authors.initials: BM
authors.lastname: Silva
mesh_terms: D000328:Adult; D001916:Brachial Artery / Q000000981:diagnostic imaging*; D005542:Forearm / Q000098:blood supply; D018737:Hand Strength; D006439:Hemodynamics; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D019194:Ischemic Preconditioning / Q000379:methods*; D008297:Male; D009119:Muscle Contraction; D018763:Muscle Fatigue; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000098:blood supply / Q000378:metabolism / Q000502:physiology*; D009211:Myoglobin / Q000378:metabolism; D055070:Resistance Training / Q000379:methods*; D013057:Spectrum Analysis; D018616:Ultrasonography, Doppler, Duplex; D055815:Young Adult
chemical_list: D006454:Hemoglobins; D009211:Myoglobin; C055547:deoxymyoglobin; C100003:deoxyhemoglobin
keywords: Performance; blood flow; deoxyhemoglobin; ischemia; vascular conductance