Acute effect of nitric oxide supplement on blood nitrate/nitrite and hemodynamic variables in resistance trained men

Journal: J. Strength Cond. Res.
Page numbers:2587-2592

Summary of Background and Research Design

Background:Nitric oxide (NO) is a natural signaling molecule that is responsible for vasodilation. Vasodilation is improves blood flow and, therefore, increase the rate of both nutrient delivery to and waste removal from skeletal muscle. Consequently, dietary strategies for increasing nitric oxide production in blood vessels could enhance performance and improve recovery. A new molecule, 2[nitrooxy]ethyl 2-amino-3-methylbutanoate is claimed to increase NO concentrations in the blood. This molecule is theoretically a direct provider of nitric oxide, as opposed to a precursor such as arginine.

Hypothesis/purpose of study:Does 2[nitrooxy]ethyl 2-amino-3-methylbutanoate affect nitrate/nitrite blood concentrations or cause hemodynamic changes (heart rate, blood pressure) in resistance trained men?

Subjects:10 resistance trained men, age 26±3 with 8 ± 6 yrs of resistance training experience, training 5 ± 3 hrs/wk.

Experimental design:Random, single-blinding, balanced crossover design

Treatments and protocol:Participants consumed 2 tablets of 2[nitrooxy]ethyl 2-amino-3-methylbutanoate subbuccally (under the tongue) or 2 capsules of placebo orally (cellulose). After 5 min, their mouths were rinsed with 12 oz of cold water. Heart rate and blood pressure were measured and venous blood was sampled at 10, 20, 35, and 65 min after the placement of the tablet or capsule in the mouth. Participants were allowed 12 oz more cold water for the duration of the study. Blood samples were treated so that all nitrate was converted to nitrite and the then total nitrite was assayed ("nitrite+nitrate" or "nitrite/nitrate" in the paper). The measurement of NO in a clinical study is problematic due to its extremely short half-life and the requirement for using costly methods such as spin trapping and electron spin resonance spectroscopy. As such, the nitric oxide metabolites (nitrates and nitrites) were measured. Also, these metabolites were measured in blood but not in muscle tissues because tissue measurements would have required muscle biopsies.

Summary of Research Findings

There were no significant main effects for treatment or time and no significant treatment X time interactions for plasma nitrite+nitrate, heart rate, systolic blood pressure, or diastolic blood pressure./kg/min, respectively).

Interpretation of findings/Key practice applications:

It is unlikely that this (undisclosed) dose of 2[nitrooxy]ethyl 2-amino-3-methylbutanoate will improve performance or recovery in resistance trained athletes. These athletes did not perform any exercise in this study, so there is a chance that 2[nitrooxy]ethyl 2-amino-3-methylbutanoate and exercise-induced stress could synergistically induce vasodilation. Also, it is not known if nitrates/nitrates might have increased at the local tissue level, even though no increases were found in the blood.
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