Nitrate Supplementation Study Supports "Increased Blood Flow ➲ Increased Performance" Claim From NO-Write-Ups
Does the vasodilatory effect of nitrates have a direct ergogenic effect that correlates with increases in blood flow? |
In said study, Julien Aucouturier et al. tried to determine whether 3 days on NO3-rich beetroot juice would boost the tolerance to supra-maximal intermittent exercise.
You can learn more about beetroot juice at the SuppVersity
periods, to failure.
Figure 1: Overview of the study design (Aucouturier. 2015). |
Before we get back to the mechanism I hinted at in the introduction, already, I want to highlight one last thing that follows from the previously highlighted result: If "only" more than 50% of the subjects benefited from the NO3- almost 50% of them didn't benefit and that's not exactly news when it comes to beetroot juice and nitrate supplementation. Previous studies showed similarly conflicting results with some suggesting that the training status of the subjects may be a significant modifier (athletes may benefit less than couch potatoes), but the reason for the differentials response of the subjects is something to investigate in another study.
So what's the news and link to NO boosters, here? What is really interesting, about the study is not the performance increase. That's no news. What is news, though, is the potential mechanism.
If we take a look at the data that is available it is obvious that the increase in exercise performance was not mediated by improvements in contractile function (maximal voluntary force during an isometric leg extensor exercise was not modified by NO3- supplementation) or resting hemodynamic parameters, which are the "usual suspects" when it comes to NO3-induced performance increases. Rather than that, the only difference that may explain the performance increase is surprisingly the previously mentioned increase in blood flow or, more specifically, the increase in microvascular total hemoglobin in the vastus lateralis muscle which was assessed by near infrared spectroscopy and increased by 18% (BJ: 9662±1228a.u. vs. placebo:8178±1589 a.u.; P<0.05).
That's not yet "prove" that it's a simple increase in blood flow that triggers the performance increase, though. After all, the scientists could simply have missed to measure another, hitherto unknown factor that triggers the performance increase,... but alas! In the end, it matters that more than 50% of the subjects saw performance increases, right? | Comment on Facebook!
References:Conventional vs. Organic Wold Premiere - First Study to Confirm: Yes! Extracts From Organic Beets Have Higher Anti-Cancer Activity Than Conventionally Grown Ones | more |
That's not yet "prove" that it's a simple increase in blood flow that triggers the performance increase, though. After all, the scientists could simply have missed to measure another, hitherto unknown factor that triggers the performance increase,... but alas! In the end, it matters that more than 50% of the subjects saw performance increases, right? | Comment on Facebook!
- Aucouturier, Julien, et al. "Effect of dietary nitrate supplementation on tolerance to supramaximal intensity intermittent exercise." Nitric Oxide (2015).