Reduced blood pressure responsiveness to skeletal muscle metaboreflex activation in older adults following inorganic nitrate supplementation

Publication date: 1 August 2018Source: Nitric Oxide, Volume 78Author(s): Aaron C. Schneider, William E. Hughes, Kenichi Ueda, Joshua M. Bock, Darren P. CaseyAbstractThe vasoactive molecule nitric oxide (NO) contributes to regulation of blood pressure (BP) at rest and during exercise. Age-related exaggerated increased BP responses during exercise have been proposed to be due in part to a decreased NO bioavailability and possibly an enhanced skeletal muscle metaboreflex. In the present study we sought to determine if age-related differences in BP responses to skeletal muscle metaboreflex activation exist. Additionally, since NO bioavailability can be improved with exogenous nitrate (NO3−) via the nitrate-nitrite-NO pathway, we tested the hypothesis that inorganic NO3− supplementation would reduce BP responses to muscle metaboreflex activation in healthy older adults. 13 older adults (67 ± 1 years) participated in a randomized, double-blind, placebo controlled crossover study consisting of four weeks of NO3− supplementation [beetroot powder; 250 mg (∼4.03 mmol) of NO3− and 20 mg (∼0.29 mmol) of NO2−] and four weeks of placebo (beetroot powder devoid of NO3−/NO2−). Skeletal muscle metaboreflex testing consisted of isometric handgrip exercise (IHG) at 30% of maximal voluntary contraction immediately followed by post exercise forearm ischemia (PEI), which was achieved by inflation of a rapid pressure cuff (240 mmHg) around the upper arm. BP response...
Source: Nitric Oxide - Category: Chemistry Source Type: research