Effects of Dietary Omega-3 Polyunsaturated Fatty Acids on the Skeletal-Muscle Blood-Flow Response to Exercise in Rats

• Autores: Charles L. Stebbins, Lauren E. Hammel, Benjamin J. Marshal, Espen E. Spangenburg, Timothy I. Musch
• Localización: International journal of sport nutrition and exercise metabolism, ISSN 1526-484X, ISSN-e 1543-2742, Vol. 20, Nº. 6, 2010, págs. 475-486
• Idioma: inglés
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• Resumen

  • 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.