Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Date of Award

Spring 2012

Document Type


Degree Name

Master of Science (MS)


Department of Kinesiology


Antioxidative compounds found in garlic may overcome exercise-induced oxidative stress (OS) and attenuate any associated decrease in endothelial function, perhaps leading to performance improvements in high intensity exercise. The purpose of the current study was to investigate whether or not a single dose garlic supplement induced positive changes to flow-mediated dilation (FMD), a measure of nitric oxide mediated endothelial function, in young, trained adults before and after maximal exercise. Maximal oxygen consumption (VO2max) was measured to determine if any changes in FMD were associated with performance improvements. A total of 11 trained participants (aged 20.64 ± 2.25 yrs) were included in the analysis. Participants were randomized to receive either the placebo, which contained 900 mg of all-purpose flour, or 900 mg of powdered garlic three hours prior to data collection. Flow-mediated dilation measurements were taken following 20 min rest (PRE), immediately following a treadmill VO2max test (IPE), and 1-hour post-exercise (1HR). All FMD measurements were taken in the right arm. This protocol was repeated with either the placebo or garlic supplement (depending upon randomization) at least two weeks after the initial test date. Although relative (garlic = 61.20 ± 6.44 ml•kg•min-1, placebo = 59.09 ± 6.96 ml•kg•min-1, p = 0.021) and absolute (garlic = 4.57 ± 0.61 L•min-1, placebo = 4.44 ± 0.52 L•min-1, p = 0.045) VO2max were higher in the garlic trial, no significant differences were found between PRE, IPE, or 1HR- FMD (PRE garlic: 0.068 mm ± 0.032 mm, PRE placebo: 0.071 mm ± 0.051 mm, IPE garlic: 0.091 mm ± 0.119 mm, IPE placebo: 0.071 mm ± 0.084 mm, 1HR garlic: 0.084 mm ± 0.097 mm, 1HR placebo: 0.108 mm ± 0.097 mm; p = 0.479). In addition, there were no significant differences found between PRE, IPE, and 1HR peak lumen diameter measurements (p = 0.524), or between PRE, IPE, and 1HR time to peak diameter measurements (p = 0.641). The results of the current study suggest that a single-dose garlic supplement improves VO2max in young, healthy subjects but that the improvements are not related to alterations in NO bioavailability as measured by FMD.

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