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Charles L. Stebbins, Lauren E. Hammel, Benjamin J. Marshal, Espen E. Spangenberg and Timothy I. Musch

The polyunsaturated fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) affect vascular relaxation and involve factors (e.g., nitric oxide) that contribute to exercise-induced increases in skeletal-muscle blood flow (Q). The authors investigated whether DHA and EPA supplementation augments skeletal-muscle Q and vascular conductance (VC) and attenuates renal and splanchnic Q and VC in exercising rats. Rats were fed a diet of 5% lipids by weight, of which 20% was DHA and 30% EPA (PUFA group, n = 9), or 5% safflower oil (SO group, n = 8) for 6 wk. Heart rate (HR), blood pressure (MAP), and hind-limb, renal, and splanchnic Q were measured at rest and during moderate treadmill running. MAP, HR, and renal and splanchnic Q and VC were similar between the 2 groups at rest and during exercise. In the PUFA group, Q (158 ± 27 vs. 128 ± 28 ml · min−1 · 100 g−1) and VC (1.16 ± 0.21 vs. 0.92 ± 0.23 ml · min−1 · 100 g−1 · mm Hg−1) were greater in the exercising hind-limb muscle. Q and VC were also higher in 8 of 28 and 11 of 28 muscles and muscle parts, respectively. These increases were positively correlated to the percent sum of Types I and IIa fibers. Results suggest that DHA+EPA (a) enhances Q and VC in active skeletal muscle (especially Type I and IIa fibers) and that the increase in Q is due to an increase in cardiac output secondary to increases in VC and (b) has no apparent influence on vasoconstriction in renal and splanchnic tissue.

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Alexandre G. da Silva, Mauricio M. Ribeiro, Ivani C. Trombetta, Christiane Nicolau, Eliana Frazzatto, Isabel Guazzelli, Luciana N. J. Matos, Alfredo Halpern, Carlos E. Negrão and Sandra M.F. Villares

This study examined forearm vasodilatation during mental challenge and exercise in 72 obese children (OC; age = 10 ± 0.1 years) homozygous with polymorphism in the allele 27 of the β2-adrenoceptors: Gln27 (n = 61) and Glu27 (n = 11). Forearm blood flow was recorded during 3 min of each using the Stroop color-word test (MS) and handgrip isometric exercise. Baseline hemodynamic and vascular measurements were similar. During the MS, peak forearm vascular conductance was significantly greater in group Glu27 (Δ = 0.35 ± 0.4 vs. 0.12 ± 0.1 units, respectively, p = .042). Similar results were found during exercise (Δ = 0.64 ± 0.1 vs. 0.13 ± 0.1 units, respectively, p = .035). Glu27 OC increased muscle vasodilatory responsiveness upon the MS and exercise.

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Ryan S. Garten, Matthew C. Scott, Tiffany M. Zúñiga, Austin C. Hogwood, R. Carson Fralin and Jennifer Weggen

changes in perfusion pressure. The current study only reported LBF changes in response to PLM. Future studies utilizing this technique and examining the impact of exercise on sedentary activity would benefit from evaluating PLM responses as leg vascular conductance, as well as LBF, to gain further insight

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Øyvind Skattebo, Thomas Losnegard and Hans Kristian Stadheim

contributes, together with a lower vascular conductance, 17 to the ∼10% lower VO 2 peak observed in DP. Recently, it was suggested that training designed to enhance O 2 extraction in the arms, such as high-volume, low-intensity upper-body training, could improve the DP VO 2 peak/VO 2 max ratio. 18

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Ozcan Esen, Ceri Nicholas, Mike Morris and Stephen J. Bailey

− supplementation can improve performance in highly trained athletes in events where a large muscle mass is recruited, and the upper body musculature is heavily engaged, such as kayaking 6 and rowing. 7 Compared to leg exercise, exercise efficiency, vascular conductance, and muscle O 2 extraction are compromised

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Robert MacKenzie, Linda Monaghan, Robert A. Masson, Alice K. Werner, Tansinee S. Caprez, Lynsey Johnston and Ole J. Kemi

. Br J Sports Med . 2003 ; 37 : 420 – 424 . PubMed ID: 14514533 doi: 10.1136/bjsm.37.5.420 14514533 19. Ferguson RA , Brown MD . Arterial blood pressure and forearm vascular conductance responses to sustained and rhythmic isometric exercise and arterial occlusion in trained rock climbers and

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Pedro L. Valenzuela, Guillermo Sánchez-Martínez, Elaia Torrontegi, Javier Vázquez-Carrión, Manuela González, Zigor Montalvo and Grégoire P. Millet

—might stimulate the upregulation of the glycolytic pathway, improve vascular conductance, enhance the skeletal muscle buffering capacity, and promote mitochondrial biogenesis or angiogenesis. 4 , 6 The hypoxic stimulus can also be applied locally by restricting oxygen supply to the exercised muscles (BFR, ie

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Declan J. Ryan, Jorgen A. Wullems, Georgina K. Stebbings, Christopher I. Morse, Claire E. Stewart and Gladys L. Onambele-Pearson

38. Dinenno FA , Jones PP , Seals DR , Tanaka H . Limb blood flow and vascular conductance are reduced with age in healthy humans relation to elevations in sympathetic nerve activity and declines in oxygen demand . Circulation . 1999 ; 100 ( 2 ): 164 – 170 . PubMed doi:10.1161/01.CIR

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Melitta A. McNarry

) athletes may be indicative of an enhanced O 2 delivery to the muscle enabling faster V ˙ O 2 kinetics, in accordance with studies in adults reporting faster conduit artery flow and vascular conductance following training ( 65 , 97 ). However, it is important to note that increased bulk O 2 delivery in