Vascular reactivity in femoral arteries of aged rats following resistance exercise training

Abstract

Previous studies have demonstrated an increase in arterial stiffness and endothelial dysfunction in aging arteries. Although it is well known that resistance training counteracts losses of muscular strength with age and subsequent loss in quality of life, few studies have examined the effects of resistance training on vascular function. Young (9 mo) and aged (24 mo) male, Fisher 344 rats were divided into four groups: Young Sedentary (YS, n=10), Young Trained (YT, n=10), Aged Sedentary (AS, n=9), and Aged Trained (AT, n=9). Resistance training consisted of climbing a 1 m wire ladder, at an 85o angle, 3d/wk for 7 weeks with increasing weight added to the tail. Vascular reactivity was examined by constructing dose response curves to phenylephrine (PE, 10−7‐10−4 M), sodium nitroprusside (SNP, 10−8‐10−5 M), and acetylcholine (ACh, 10−7‐3x10−5 M). Vasocontrictor responses to PE were significantly (P<0.05) greater in Aged versus Young. Vasodilator responses to both SNP and ACh were significantly impaired in AS but were improved in AT. In conclusion, these data suggest that resistance exercise training results in a shift in the vasoreactivity of aged animals towards that of younger animals which includes both a blunted vasoconstrictor response and enhanced vasorelaxation. The mechanisms underlying this shift remain to be determined. Supported by NIH R15 HL082649‐01 (MBH) and the Borgenicht Program for Aging Studies and Exercise Science (MBH).