Study under review: The effects of multi-day vs. Single preexercise nitrate supplement dosing on simulated cycling time trial performance and skeletal muscle oxygenation
Nitric oxide is a small molecule made in the body that plays a variety of roles. One such role is as a vasodilator, meaning that it relaxes blood vessels and aids in blood flow. Since muscles need the oxygen and nutrients in the blood in order to function well, it’s possible that nitric oxide may enhance exercise performance and muscle function.
One way to enhance nitric oxide production is via ingestion of exogenous nitrates (i.e. nitrate supplements or nitrate-containing foods, as shown in Figure 1). Other supplements like L-citrulline and L-arginine might also boost nitric oxide, but some researchers argue that L-arginine is relatively ineffective for this purpose. This is one the reasons why nitrates are particularly promising.
Adapted from: Lundberg et al. Cardiovasc Res. 2011 Feb.
The promise of nitrate supplementation has panned out in some studies linking nitrates to improved blood flow and blood pressure. In addition, nitrate supplementation with beetroot juice might decrease the oxygen cost of running, and reduce maximal oxygen consumption during exercise. Hence, nitrates could improve exercise economy and performance.
Yet with all these benefits, researchers are still trying to figure out how long nitrates need to be taken before they improve performance. Is it enough to take a nitrate supplement right before an exercise session or competition, or should it be taken daily for a more extended period? In other words, is there a difference between single-day and multi-day nitrate supplementation? This is what the study under review sought to answer.
Nitrates might improve blood flow, blood pressure, exercise performance, and exercise economy. However, it’s unclear whether there is a difference between single dosing before a session compared to chronic dosing. The study under review was designed to determine whether two weeks of daily nitrate supplementation was more effective than single-day supplementation for muscle oxygenation and cycling performance.
Other Articles in Issue #32 (June 2017)
Another look at the diet-heart hypothesis
When you replace saturated fat with polyunsaturated fat, some studies suggest that good things should happen. But there’s more than one way to interpret the available studies.
Can chondroitin save knee cartilage?
Chondroitin’s mixed results for slowing the progression of osteoarthritis may be due to the low-quality or lower-dose chondroitin used in some studies. Looking at the structural effects of higher-dose, pharmaceutical-grade chondroitin could shed more light on its efficacy
Protein, fast and slow
Fast-digesting whey helps with post-workout muscle protein synthesis, and some studies suggest slower-digesting casein reduces muscle protein breakdown. This opens the possibility that their combination could be better than either alone
Timing protein before bed for gains
Sleep is one big fast, which could put muscles’ protein balance into the red. Could taking slow-acting casein before bed put the balance back into the black overnight?
Interview: Matthew Dalby, PhD
Dr. Dalby’s research explores the links between diet, obesity, and the microbiome. In this interview, we discuss fecal transplants, the role of animal models in research, and more.
Should 1000 IU be the new RDA for vitamin D?
Since it was set in 2010, the 600 IU vitamin D RDA has been widely circulated. But a close look at individual patient data may give a more accurate estimate of vitamin D needs.
Interview: Kenneth Brown, MD
Dr. Brown is an accomplished gastroenterologist who has conducted clinical trials on supplements and drugs for GI conditions. We pick his brain here