Effect of Acute Dietary Nitrate Supplementation on Physical Function in Older Men and Women

It is well known that physical function decreases with advancing age. This is largely a result of reduced muscle contractility, which leads to a diminished quality of life, greater dependence, and an increased risk of falling. We have repeatedly demonstrated that acute ingestion of nitrate (NO 3 - ) significantly increases maximal muscle speed and power in older individuals. It is not known, however, whether this enhanced muscle contractility results in improvements in physical function. Therefore, the purpose of the present was to test the hypothesis that dietary NO 3 - would improve physical function in older individuals. Using a double blinded, placebo-controlled, crossover design, 13 older men and women from the community (age 75 ± 6 y) were studied after acute ingestion of beetroot juice with and without NO 3 - . Physical function was assessed by 6 min walk, gait speed (both normal and fast), sit-to-stand (# in 30 s), and grip strength, while quality of life was assessed using the SF-36 questionnaire. Dietary NO 3 - supplementation had no effect on 6 min walk (506 ± 89 vs. 511 ± 94 m; p=0.58), normal gait speed (1.20 ± 0.12 vs. 1.23 ± 0.18 m/s; p=0.66), fast gait speed (1.73 ± 0.23 vs. 1.73 ± 0.21 m/s; p=0.96) or sit-to-stand performance (17 ± 4 vs. 17 ± 5; p=0.40). Acute NO 3 - ingestion also did not alter grip strength or SF-36 questionnaire responses. We conclude that acute NO 3 - ingestion does not measurably improve physical function in older men and women. Repeated dosing and/or combining NO 3 - supplementation with exercise training may be necessary to elicit significant changes. This study was supported by grant R21 AG053606 from the National Institute on Aging This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.