A Single Dose of Dietary Nitrate Increases Maximal Knee Extensor Angular Velocity and Power in Healthy Older Men and Women. (22nd July 2019)

• Record Type: Journal Article
• Authors: Coggan, Andrew R; Hoffman, Richard L; Gray, Derrick A; Moorthi, Ranjani N; Thomas, Deepak P; Leibowitz, Joshua L; Thies, Dakkota; Peterson, Linda R
• Editors: Newman, Anne
• Is Part Of: Journals of gerontology. Volume 75:Number 6(2020)
• Page Start: 1154
• Page End: 1160
• Publication Date: 2019-07-22
• Subjects: Nitric oxide -- Nitrite -- Isokinetic dynamometry -- Blood pressure; Geriatrics -- Periodicals; Gerontology -- Periodicals; 618.97
• DOI: 10.1093/gerona/glz156
• Languages: English
• ISSNs: 1079-5006

Abstract

Abstract: Background: Aging results in reductions in maximal muscular strength, speed, and power, which often lead to functional limitations highly predictive of disability, institutionalization, and mortality in elderly adults. This may be partially due to reduced nitric oxide (NO) bioavailability. We, therefore, hypothesized that dietary nitrate (N O 3 − ), a source of NO via the N O 3 − → nitrite (N O 2 − ) → NO enterosalivary pathway, could increase muscle contractile function in older subjects. Methods: Twelve healthy older (age 71 ± 5 years) men and women were studied using a randomized, double-blind, placebo-controlled, crossover design. After fasting overnight, subjects were tested 2 hours after ingesting beetroot juice containing or devoid of 13.4 ± 1.6 mmol N O 3 − . Plasma N O 3 − and N O 2 − and breath NO were measured periodically, and muscle function was determined using isokinetic dynamometry. Results: N O 3 − ingestion increased ( p < .001) plasma N O 3 −, plasma N O 2 −, and breath NO by 1, 051% ± 433%, 138% ± 149%, and 111% ± 115%, respectively. Maximal velocity of knee extension increased ( p < .01) by 10.9% ± 12.1%. Maximal knee extensor power increased ( p < .05) by 4.4% ± 7.8%. Conclusions: Acute dietary N O 3 − intake improves maximal knee extensor angular velocity and power in older individuals. These findings may have important implications for this population, in whom diminished muscle function can lead to functional limitations, dependence, and even premature death.