Effects of Nitrate Supplementation on Exercise Performance in Humans: A Narrative Review

Nitrates have become increasingly popular for their potential role as an ergogenic aid. The purpose of this article was to review the current scientific evidence of nitrate supplementation on human performance. The current recommendation of nitrate supplementation is discussed, as well as possible health complications associated with nitrate intake for athletes, and dietary strategies of covering nitrate needs through sufficient intake of nitrate-rich foods alone are presented. Pubmed, Scopus, and Web of Science were searched for articles on the effects of nitrate supplementation in humans. Nitrates are an effective ergogenic aid when taken acutely or chronically in the range of ~5–16.8 mmol (~300–1041 mg) 2–3 h before exercise and primarily in the case of exercise duration of ~10–17 min in less trained individuals (VO2max < 65 mL/kg/min). Nitrate needs are most likely meet by ingesting approximately 250–500 g of leafy and root vegetables per day; however, dietary supplements might represent a more convenient and accurate way of covering an athlete’s nitrate needs. Athletes should refrain from mouthwash usage when nitrate supplementation benefits are desired. Future research should focus on the potential beneficial effects of nitrate supplementation on brain function, possible negative impacts of chronic nitrate supplementation through different nitrate sources, and the effectiveness of nitrate supplementation on strength and high-intensity intermittent exercise.

Taurine in sports and exercise

Background Taurine has become a popular supplement among athletes attempting to improve performance. While the effectiveness of taurine as an ergogenic aid remains controversial, this paper summarizes the current evidence regarding the efficacy of taurine in aerobic and anaerobic performance, metabolic stress, muscle soreness, and recovery. Methods Google Scholar, Web of Science, and MedLine (PubMed) searches were conducted through September 2020. Peer-reviewed studies that investigated taurine as a single ingredient at dosages of < 1 g - 6 g, ranging from 10 to 15 min-to-2 h prior to exercise bout or chronic dose (7 days- 8 weeks) of consumption were included. Articles were excluded if taurine was not the primary or only ingredient in a supplement or food source, not published in peer-reviewed journals, if participants were older than 50 years, articles published before 1999, animal studies, or included participants with health issues. A total of 19 studies met the inclusion criteria for the review. Results Key results include improvements in the following: VO2max, time to exhaustion (TTE; n = 5 articles), 3 or 4 km time-trial (n = 2 articles), anaerobic performance (n = 7 articles), muscle damage (n = 3 articles), peak power (n = 2 articles), recovery (n = 1 article). Taurine also caused a change in metabolites: decrease in lactate, creatine kinase, phosphorus, inflammatory markers, and improved glycolytic/fat oxidation markers (n = 5 articles). Taurine dosing appears to be effective at ~ 1–3 g/day acutely across a span of 6–15 days (1–3 h before an activity) which may improve aerobic performance (TTE), anaerobic performance (strength, power), recovery (DOMS), and a decrease in metabolic markers (creatine kinase, lactate, inorganic phosphate). Conclusions Limited and varied findings prohibit definitive conclusions regarding the efficacy of taurine on aerobic and anaerobic performance and metabolic outcomes. There are mixed findings for the effect of taurine consumption on improving recovery from training bouts and/or mitigating muscle damage. The timing of taurine ingestion as well as the type of exercise protocol performed may contribute to the effectiveness of taurine as an ergogenic aid. More investigations are needed to better understand the potential effects of taurine supplementation on aerobic and anaerobic performance, muscle damage, metabolic stress, and recovery.

REVIEW ON ERGOGENIC EFFECT OF WITHANIA SOMNIFERA (L.) DUNAL

Withania Somnifera (L.) Dunal is a commonly used herb in the alternative medical systems in the world. It is been investigated under several aspects of sports science due to athlete friendly benefits. The collective traits of performance enhancing consequence of an athlete can be described under the term ‘ergogenic ef-fect’. Though the herb is not been investigated as an ergogenic aid, the scattered scientific studies can pre-view its’ skill, strength, endurance and recovery promoting ability after competitions. The study was aimed to analyze its’ ergogenic effect using scientific evidences and classical Ayurveda references. Research data was collected from the online sources and classical Ayurveda references. Withania Somnifera found to be enhanced aerobic and anerobic exercise capacity, muscle strength, recovery process, anti-fatigue activity, endurance and immune-modulatory effect. Ayurveda literature also supports these evidences as it has been described as a Balya, Brimhana, Vatahara, Kaphahara and Shukrala herb. Correlation between these two concepts also suggests Withania Somnifera as an effective ergogenic aid.

Neuronal adenosine A2A receptors signal ergogenic effects of caffeine

Ergogenic aid is a substance or method used for enhancing exercise and sports performance. Caffeine is the most used ergogenic aid for athletes, but the mechanisms are still unknown. Forty-two adult female (19±0.6 g) and 40 male mice (24±0.4 g) from a global and forebrain A2AR knockout and colony (FMUC, University of Coimbra) underwent an open field and ergospirometry exercise test. Caffeine (15 mg/kg, i.p.) and SCH 58261 (1 mg/kg, i.p.) were administered 15 minutes before the animals ran to exhaustion. We also evaluate the estrous cycle and infrared temperature (rest and recovery). Caffeine was psychostimulant in wild type females and males, but we observed this expected effect of SCH-58261 only in males. Caffeine and SCH-58261 were also ergogenic for wild type animals, that is, they increased running power and maximal O2 consumption (O2max). The psychostimulant and ergogenic effects of caffeine and SCH-58261 disappeared in A2AR knockout females (global) and males (forebrain). The estrous cycle did not influence any evaluated parameters, as well as exercise-induced hyperthermia was similar between savages and knockouts. Our results suggest that the neuronal A2AR receptors signal the ergogenic effects of caffeine in female and male mice.

Is Coffee a Useful Source of Caffeine Preexercise?

Caffeine is a well-established ergogenic aid, with its performance-enhancing effects demonstrated across a wide variety of exercise modalities. Athletes tend to frequently consume caffeine as a performance enhancement method in training and competition. There are a number of methods available as a means of consuming caffeine around exercise, including caffeine anhydrous, sports drinks, caffeine carbohydrate gels, and gum. One popular method of caffeine ingestion in nonathletes is coffee, with some evidence suggesting it is also utilized by athletes. In this article, we discuss the research pertaining to the use of coffee as an ergogenic aid, exploring (a) whether caffeinated coffee is ergogenic, (b) whether dose-matched caffeinated coffee provides a performance benefit similar in magnitude to caffeine anhydrous, and (c) whether decaffeinated coffee consumption affects the ergogenic effects of a subsequent isolated caffeine dose. There is limited evidence that caffeinated coffee has the potential to offer ergogenic effects similar in magnitude to caffeine anhydrous; however, this requires further investigation. Coingestion of caffeine with decaffeinated coffee does not seem to limit the ergogenic effects of caffeine. Although caffeinated coffee is potentially ergogenic, its use as a preexercise caffeine ingestion method represents some practical hurdles to athletes, including the consumption of large volumes of liquid and difficulties in quantifying the exact caffeine dose, as differences in coffee type and brewing method may alter caffeine content. The use of caffeinated coffee around exercise has the potential to enhance performance, but athletes and coaches should be mindful of the practical limitations.

Exogenous Carbohydrate as an Ergogenic Aid: Recent Advances in Dose and Form and Format

Performance nutrition is as wide and complex topic as the number and diversity of sports available for human endeavor [...]