Resistance exercise training improves age-related declines in leg vascular conductance and rejuvenates acute leg blood flow responses to feeding and exercise

Abstract

I, Rennie MJ. Resistance exercise training improves age-related declines in leg vascular conductance and rejuvenates acute leg blood flow responses to feeding and exercise. J Appl Physiol 112: 347-353, 2012. First published October 13, 2011 doi:10.1152/japplphysiol.01031.2011.-One manifestation of age-related declines in vascular function is reduced peripheral (limb) blood flow and vascular conduction at rest and in response to vasodilatory stimuli such as exercise and feeding. Since, even in older age, resistance exercise training (RET) represents an efficacious strategy for increasing muscle mass and function, we hypothesized that likewise RET would improve age-related declines in leg blood flow (LBF) and vascular conductance (LVC). We studied three mixed-sex age groups (young: 18 -28 yr, n ϭ 14; middle aged: 45-55 yr, n ϭ 20; older: 65-75 yr, n ϭ 17) before and after 20 wk of whole body RET in the postabsorptive state (BASAL) and after unilateral leg extensions (6 ϫ 8 repetitions; 75% 1 repetition maximum) followed by intermittent mixed-nutrient liquid feeds (ϳ6.5 kJ·kg Ϫ1 ·30 min Ϫ1 ), which allowed us to discern the acute effects of feeding (nonexercised leg; FED) and exercise plus feeding (exercised leg; FEDEX) on vascular function. We measured LBF using Doppler ultrasound and recorded mean arterial pressure (MAP) to calculate LVC. Our results reveal that although neither age nor RET influenced BASAL LBF, age-related declines in LBF responses to FED were eradicated by RET. Moreover, increases in LBF after FEDEX, which occurred only in young and middle-aged groups before RET (ϩ73 Ϯ 9%, and ϩ90 Ϯ 13%, P Ͻ 0.001, respectively), increased in all groups after RET (young ϩ78 Ϯ 10%, middle-aged ϩ96 Ϯ 15%, older ϩ80 Ϯ 19%, P Ͻ 0.001). Finally, RET robustly improved LVC under FASTED, FED, and FEDEX conditions in the older group. These data provide novel information that supports the premise that RET represents a valuable strategy to counter age-related impairments in LBF/LVC. circulation; nutrition; muscle HUMAN AGEING is associated with decreased arterial compliance, which leads to hypertension and coronary artery disease (10,11,20) such that cardiovascular disease-related morbidity and mortality increase markedly with age. Declines in peripheral (i.e., limb arterial) blood flow and increases in vascular resistance are one such characteristic manifestation of cardiovascular ageing. For example, Donato et al. (13) reported that older individuals exhibit 20 -30% lower resting, postabsorptive limb blood flow and a ϳ50% decrease in leg vascular conductance (LVC) compared with younger individuals. Such age-related changes are purported to contribute to the metabolic syndrome, a major precursor to atherosclerotic disease in humans that encompasses hyperinsulinemia, dyslipidemia, and hypertension (20).Intriguingly, declines in peripheral blood flow with ageing are not restricted to postabsorptive periods but are also observed when subjects are challenged with vasodilatory stimuli, such as food intake (31) and exercise ...

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