The Study
Two weeks of watermelon juice supplementation improves nitric oxide bioavailability but not endurance exercise performance in humans.
This study gave 8 guys watermelon juice and saw some changes in their blood, but didn't make them run longer. It's like noticing your phone battery lasts longer after a software update—you see a change, but you don't know if it's because of the update or something else.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Scientists gave men watermelon juice for two weeks to see if it helped them exercise better.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 546 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Even though the body made more nitric oxide and muscles got more oxygen during light exercise, the extra energy didn't help them push harder or longer during intense workouts, and their blood pressure rose instead of falling.
- 2Nitric oxide went up 97%, muscles got more oxygen during moderate exercise, but blood pressure went up 6 mmHg and they didn't last longer during hard exercise.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Nitric oxide : biology and chemistry
Year
2016
Authors
S. Bailey, Jamie R. Blackwell, Ewan R. Williams, A. Vanhatalo, L. Wylie, P. Winyard, A. Jones
Related Content
Claims (4)
Daily consumption of 300 mL of watermelon juice concentrate containing 3.4 grams of L-citrulline for 16 days raises plasma nitrite levels by about 97% and improves oxygen delivery to skeletal muscles during moderate exercise in healthy adult males, but does not extend the time until exhaustion during high-intensity exercise.
Drinking watermelon juice does not make healthy active men last longer during high-intensity exercise, even though it raises plasma nitrite levels and improves muscle oxygenation during moderate exercise.
Drinking 300 mL of watermelon juice concentrate daily for 16 days raises resting systolic blood pressure by about 6 mmHg in healthy, active adult men, even though it also raises markers of nitric oxide in the blood.
Watermelon contains more citrulline than any other food, and citrulline is converted in the body to nitric oxide.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.