19 research outputs found
Impact of dietary nitrate dose on resistance exercise performance
The purpose of this study was to assess whether various doses of BR supplementation can influence muscle performance during a battery of resistance exercises in healthy, resistance-trained males. In a double-blind, randomized crossover design, 18 males were randomly allocated to consume 4 x 70 ml of BR over four conditions: (1) 4 x 70 ml of nitrate-depleted BR for placebo (PL); (2) 1 x 70 ml of nitrate-rich BR and 3 x 70 ml of PL for a low nitrate dose (BR-LOW); (3) 2 x 70 ml of nitrate-rich BR and 2 x 70 ml of PL for a moderate nitrate dose (BR-MOD); and (4) 4 x 70 ml of nitrate-rich BR for an elevated nitrate dose (BR-HIGH). Participants reported to the laboratory 5 times over 5-wk. Following a 1 repetition max (1RM) and a familiarization to the exercise protocol, participants completed a warm up and then a protocol to assess explosive performance using a linear transducer and force plate during vertical countermovement jumps, and then back squat and bench press, in a randomized order. A resting blood sample was drawn for the determination of plasma nitrate and nitrite concentrations. A two way repeated measures ANOVA was used to determine statistical differences between blood and performance variables, and is currently in progress. These data could provide insight for dietary nitrate as an ergogenic aid and inform both supplementation guidelines and recommendations for enhancing resistance training performance in men
Co-Ingestion of Dietary Nitrate and Ascorbic Acid on Nitric Oxide Biomarkers and The Oral Microbiome in Sedentary Hispanic Women
Nitric oxide bioavailability increases following nitrate supplementation wherein oral microbiota facilitate the metabolism and absorption of nitrate. However, few studies have examined if co-ingestion of nitrate with antioxidants can further elevate nitric oxide bioavailability. Moreover, our understanding on how the oral microbiome responds to nitrate supplementation is limited, especially in women. PURPOSE: To examine the effects of ingesting dietary nitrate and ascorbic acid independently and concurrently on markers of nitric oxide bioavailability and oral microbiota species. METHODS: Twelve sedentary women of Hispanic descent (mean ± SD: age 20 ± 1 years; body mass 74 ± 15 kg; height 1.62 ± 0.09 m) consumed nitrate-rich beetroot juice (BR), nitrate-depleted beetroot juice (PL), ascorbic acid (AA), and crystal light (CRY) in four conditions: BR combined with AA (BR+AA); BR only (BR+CRY); AA only (PL+AA); and placebo-control (PL+CRY). Supplements were ingested 2.5 hours prior to a resting blood draw and buccal swab sample. Plasma [nitrate] and [nitrite] were analyzed using gas phase chemiluminescence. Buccal swab samples were used for DNA extraction and isolation. DNA was amplified using polymerase chain reaction (PCR) targeting the V3 - V4 region of the 16S rRNA gene. Following index PCR, amplicons were pooled and sequenced using the iSeq Illumina NGS sequencer. Reads were clustered into amplicon sequence variants and analyzed for alpha and beta diversity and relative abundance. RESULTS: BR increased plasma [nitrate] (BR+AA: 641 ± 252 vs. BR+CRY: 528 ± 307 vs. PL+AA: 35 ± 10 vs. PL+CRY: 35 ± 12 µM, P \u3c 0.001) and plasma [nitrite] (BR+AA: 710 ± 336 vs. BR+CRY: 578 ± 428 vs. PL+AA: 209 ± 88 vs. PL+CRY: 198 ± 82 nM, P \u3c 0.001) with no differences within BR and PL conditions. Alpha and beta diversity, and the relative abundance of higher and lower taxonomic levels were not significantly different between all conditions (P \u3e 0.05) CONCLUSION: Concurrent nitrate and AA supplementation did not elicit additional increases to nitric oxide compared to nitrate ingestion alone. Acute beetroot juice and ascorbic acid were ineffective at modulating oral microbial composition. Further research is required to understand the impact of supplementation regimen and population on the physiological effects of dietary nitrate
Effects of Co-ingesting Dietary Nitrate and Vitamin C on Nitric Oxide Bioavailability, Blood Pressure, and Cardiovascular Reactivity in Hispanic Females
High blood pressure is a hallmark of chronic disease and is disproportionately prevalent in ethnic minorities. Dietary nitrate has been shown to lower blood pressure via increased nitric oxide (NO), but few studies have examined if combining nitrate with vitamin C (VITC) could have beneficial synergistic effects on blood pressure by augmenting NO, and limited data exist in females. PURPOSE: To investigate if combining nitrate-rich beetroot juice (BR) with VITC could further augment NO bioavailability and improve blood pressure in Hispanic females compared to BR and VITC ingested alone. METHODS: Eight sedentary Hispanic females participated in four conditions to ingest: 1) BR and VITC (BR+VITC), 2) BR and crystal light (BR+CRY), 3) nitrate-depleted BR and VITC (PL+VITC), and 4) PL and CRY (PL+CRY). A blood draw and blood pressure were obtained at rest, followed by a cardiovascular reactivity test. RESULTS: Plasma nitrate was increased in BR+VITC and BR+CRY compared to PL+VITC and PL+CRY (P0.05). Plasma nitrite was increased in BR+VITC and BR+CRY compared to PL+VITC and PL+CRY (P0.05). CONCLUSION: Co-ingestion of dietary nitrate and VITC increased plasma nitrite compared to BR alone, which could indicate augmented NO bioavailability following BR+VITC; however, there was no impact of nitrate supplementation on markers of cardiovascular health
The Effects of Acute Beetroot Juice Ingestion on Exercise and Cognitive Performance in Female Athletes
Nitrate-rich beetroot juice can enhance intense exercise performance which is attributed to enhanced skeletal muscle contractility. However, limited data exist in females and it is unknown whether dietary nitrate has an ergogenic effect in this population. PURPOSE: To investigate the potential effects of acute nitrate ingestion on a battery of exercise performance and cognitive tests before and after fatiguing intermittent running exercise. METHODS: Fifteen female team-sport athletes were assigned in a randomized, double-blind, crossover design to consume nitrate-rich beetroot juice (BR; 12 mmol of nitrate) and nitrate-depleted beetroot juice (PL; 0.10 mmol of nitrate) 2.5 h prior to performing the exercise protocol, with a washout period of 7 days between trials. Running 10 m and 20 m sprint split times, sprint reaction time, upper- and lower-body power, handgrip strength, and cognitive flexibility were measured before and after the Yo-Yo intermittent recovery level 1 (Yo-Yo IR1) test, during which performance and rate of perceived exertion were recorded. RESULTS: There were no significant differences in any performance outcome or cognitive flexibility (P \u3e 0.05). CONCLUSION: These findings indicate that acute nitrate ingestion does not influence performance in sprints, intermittent running, power, strength, or cognitive function in young adult female team-sport athletes
Effects of Dietary Nitrate Supplementation on Performance and Muscle Oxygenation during Resistance Exercise in Men
The purpose of the current study was to assess the effects of acute and short-term nitrate (NO3−)-rich beetroot juice (BR) supplementation on performance outcomes and muscle oxygenation during bench press and back squat exercise. Fourteen recreationally active males were assigned in a randomized, double-blind, crossover design to supplement for 4 days in two conditions: (1) NO3−-depleted beetroot juice (PL; 0.10 mmol NO3− per day) and (2) BR (11.8 mmol NO3− per day). On days 1 and 4 of the supplementation periods, participants completed 2 sets of 2 × 70%1RM interspersed by 2 min of recovery, followed by one set of repetitions-to-failure (RTF) at 60%1RM for the determination of muscular power, velocity, and endurance. Quadriceps and pectoralis major tissue saturation index (TSI) were measured throughout exercise. Plasma [NO3−] and nitrite ([NO2−]) were higher after 1 and 4 days of supplementation with BR compared to PL (p \u3c 0.05). Quadriceps and pectoralis major TSI were not different between conditions (p \u3e 0.05). The number of RTF in bench press was 5% greater after acute BR ingestion compared to PL (PL: 23 ± 4 vs. BR: 24 ± 5, p \u3c 0.05). There were no differences between BR and PL for RTF for back squat or power and velocity for back squat or bench press (p \u3e 0.05). These data improve understanding on the ergogenic potential of BR supplementation during resistance exercise
Effects of Dietary Nitrate Supplementation on High-Intensity Cycling Sprint Performance in Recreationally Active Adults: A Systematic Review and Meta-Analysis
This systematic review and meta-analysis investigated the influence of dietary nitrate supplementation on performance metrics during cycling sprint exercise according to the PRISMA guidelines. Searches were conducted on MEDLINE, PubMed, ScienceDirect, Scopus, and SPORTDiscus databases up to September 2023. Inclusion criteria were healthy recreationally active men and women who consumed nitrate-rich and nitrate-deficient beetroot juice to assess performance outcomes of mean power, peak power, time-to-peak power, and minimum power during 30-s cycling sprints. Risk of bias was assessed using the Cochrane Risk of Bias 2 and TESTEX tools and funnel plots. A random effects model was performed on six studies and showed that dietary nitrate had significant effects on time-to-peak power (SMD: −0.66, 95% CI: −1.127 to −0.192, p = 0.006) but not on mean power, peak power, or minimum power. Subgroup analysis revealed that an acute low nitrate dose improved time-to-peak power (SMD: −0.977, 95% CI: −1.524 to −0.430, p < 0.001) but not after a multiday moderate nitrate dose (SMD: −0.177, 95% CI: −0.619 to −0.264, p = 0.431). These data suggest that acute nitrate supplementation can benefit time-to-peak power during 30-s cycling sprints, but due to the limited availability of data and heterogeneity in methodology, these results should be interpreted with caution. There was insufficient data on women to analyze sex-based differences. Future studies are required to provide insight on how supplementation regimen and population impact the effects of dietary nitrate for enhancing cycling sprint performance
Path dependence and the stabilization of strategic premises: how the funeral industry buries itself
Effects of Dietary Nitrate Supplementation on Performance and Muscle Oxygenation during Resistance Exercise in Men
The purpose of the current study was to assess the effects of acute and short-term nitrate (NO3−)-rich beetroot juice (BR) supplementation on performance outcomes and muscle oxygenation during bench press and back squat exercise. Fourteen recreationally active males were assigned in a randomized, double-blind, crossover design to supplement for 4 days in two conditions: (1) NO3−-depleted beetroot juice (PL; 0.10 mmol NO3− per day) and (2) BR (11.8 mmol NO3− per day). On days 1 and 4 of the supplementation periods, participants completed 2 sets of 2 × 70%1RM interspersed by 2 min of recovery, followed by one set of repetitions-to-failure (RTF) at 60%1RM for the determination of muscular power, velocity, and endurance. Quadriceps and pectoralis major tissue saturation index (TSI) were measured throughout exercise. Plasma [NO3−] and nitrite ([NO2−]) were higher after 1 and 4 days of supplementation with BR compared to PL (p 0.05). The number of RTF in bench press was 5% greater after acute BR ingestion compared to PL (PL: 23 ± 4 vs. BR: 24 ± 5, p 0.05). These data improve understanding on the ergogenic potential of BR supplementation during resistance exercise
Effects of dietary nitrate supplementation on performance and muscle oxygenation during resistance exercise in men
The purpose of the current study was to assess the effects of acute and short-term nitrate (NO3−)-rich beetroot juice (BR) supplementation on performance outcomes and muscle oxygenation during bench press and back squat exercise. Fourteen recreationally active males were assigned in a randomized, double-blind, crossover design to supplement for 4 days in two conditions: (1) NO3−-depleted beetroot juice (PL; 0.10 mmol NO3− per day) and (2) BR (11.8 mmol NO3− per day). On days 1 and 4 of the supplementation periods, participants completed 2 sets of 2 × 70%1RM interspersed by 2 min of recovery, followed by one set of repetitions-to-failure (RTF) at 60%1RM for the determination of muscular power, velocity, and endurance. Quadriceps and pectoralis major tissue saturation index (TSI) were measured throughout exercise. Plasma [NO3−] and nitrite ([NO2−]) were higher after 1 and 4 days of supplementation with BR compared to PL (p 0.05). The number of RTF in bench press was 5% greater after acute BR ingestion compared to PL (PL: 23 ± 4 vs. BR: 24 ± 5, p 0.05). These data improve understanding on the ergogenic potential of BR supplementation during resistance exercise.</p