***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: It is possible that dietary nitrate ( NO3− ) supplementation may improve both physical and cognitive performance via its influence on blood flow and cellular energetics . Purpose To investigate the effects of dietary NO3− supplementation on exercise performance and cognitive function during a prolonged intermittent sprint test ( IST ) protocol , which was design ed to reflect typical work patterns during team sports . Methods In a double-blind r and omised crossover study , 16 male team-sport players received NO3−-rich ( BR ; 140 mL day−1 ; 12.8 mmol of NO3− ) , and NO3−-depleted ( PL ; 140 mL day−1 ; 0.08 mmol NO3− ) beetroot juice for 7 days . On day 7 of supplementation , subjects completed the IST ( two 40-min “ halves ” of repeated 2-min blocks consisting of a 6-s “ all-out ” sprint , 100-s active recovery and 20 s of rest ) , on a cycle ergometer during which cognitive tasks were simultaneously performed . Results Total work done during the sprints of the IST was greater in BR ( 123 ± 19 kJ ) compared to PL ( 119 ± 17 kJ ; P < 0.05 ) . Reaction time of response to the cognitive tasks in the second half of the IST was improved in BR compared to PL ( BR first half : 820 ± 96 vs. second half : 817 ± 86 ms ; PL first half : 824 ± 114 vs. second half : 847 ± 118 ms ; P < 0.05 ) . There was no difference in response accuracy . Conclusions These findings suggest that dietary NO3−  enhances repeated sprint performance and may attenuate the decline in cognitive function ( and specifically reaction time ) that may occur during prolonged intermittent exercise Nitrate supplementation appears to be most ergogenic when oxygen availability is restricted and subsequently may be particularly beneficial for swimming performance due to the breath-hold element of this sport . This represents the first investigation of nitrate supplementation and swimming time-trial ( TT ) performance . In a r and omized double-blind repeated- measures crossover study , ten ( 5 male , 5 female ) trained swimmers ingested 140ml nitrate-rich ( ~12.5mmol nitrate ) or nitrate-depleted ( ~0.01mmol nitrate ) beetroot juice . Three hours later , subjects completed a maximal effort swim TT comprising 168 m ( 8 × 21 m lengths ) backstroke . Preexercise fractional exhaled nitric oxide concentration was significantly elevated with nitrate compared with placebo , Mean ( SD ) : 17 ( 9 ) vs. 7 (3)p.p.b . , p = .008 . Nitrate supplementation had a likely trivial effect on overall swim TT performance ( mean difference 1.22s ; 90 % CI -0.18 - 2.6s ; 0.93 % ; p = .144 ; d = 0.13 ; unlikely beneficial ( 22.6 % ) , likely trivial ( 77.2 % ) , most unlikely negative ( 0.2 % ) ) . The effects of  nitrate supplementation  during the first half of the TT were trivial ( mean difference 0.29s ; 90 % CI -0.94 - 1.5s ; 0.46 % ; p = .678 ; d = 0.05 ) , but there was a possible beneficial effect of nitrate supplementation during the second half of the TT ( mean difference 0.93s ; 90 % CI 0.13 - 1.70s ; 1.36 % ; p = .062 ; d = 0.24 ; possibly beneficial ( 63.5 % ) , possibly trivial ( 36.3 % ) , most unlikely negative ( 0.2 % ) ) . The duration and speed of underwater swimming within the performance did not differ between nitrate and placebo ( both p > .30 ) . Nitrate supplementation increased nitric oxide bioavailability but did not benefit short-distance swimming performance or the underwater phases of the TT . Further investigation into the effects of nitrate supplementation during the second half of performance tests may be warranted The influence of dietary nitrate ( NO3- ) supplementation on indices of maximal sprint and intermittent exercise performance is unclear . PURPOSE To investigate the effects of NO3- supplementation on sprint running performance , and cognitive function and exercise performance during the sport-specific Yo-Yo Intermittent Recovery level 1 test ( IR1 ) . METHODS In a double-blind , r and omized , crossover study , 36 male team-sport players received NO3 - -rich ( BR ; 70 mL·day-1 ; 6.4 mmol of NO3- ) , and NO3 - -depleted ( PL ; 70 mL·day-1 ; 0.04 mmol NO3- ) beetroot juice for 5 days . On day 5 of supplementation , subjects completed a series of maximal 20-m sprints followed by the Yo-Yo IR1 . Cognitive tasks were completed prior to , during and immediately following the Yo-Yo IR1 . RESULTS BR improved sprint split times relative to PL at 20 m ( 1.2 % ; BR 3.98 ± 0.18 vs. PL 4.03 ± 0.19 s ; P < 0.05 ) , 10 m ( 1.6 % ; BR 2.53 ± 0.12 vs. PL 2.57 ± 0.19 s ; P < 0.05 ) and 5 m ( 2.3 % ; BR 1.73 ± 0.09 vs. PL 1.77 ± 0.09 s ; P < 0.05 ) . The distance covered in the Yo-Yo IR1 test improved by 3.9 % ( BR 1422 ± 502 vs. PL 1369 ± 505 m ; P < 0.05 ) . The reaction time to the cognitive tasks was shorter in BR ( 615 ± 98 ms ) than PL ( 645 ± 120 ms ; P < 0.05 ) at rest but not during the Yo-Yo IR1 . There was no difference in response accuracy . CONCLUSIONS Dietary NO3- supplementation enhances maximal sprint and high-intensity intermittent running performance in competitive team sport players . Our findings suggest that NO3- supplementation has the potential to improve performance in single-sprint or multiple-sprint ( team ) sports INTRODUCTION Dietary nitrate supplementation has received much attention in the literature due to its proposed ergogenic properties . Recently , the ingestion of a single bolus of nitrate-rich beetroot juice ( 500 ml , ~6.2 mmol NO3- ) was reported to improve subsequent time-trial performance . However , this large volume of ingested beetroot juice does not represent a realistic dietary strategy for athletes to follow in a practical , performance-based setting . Therefore , we investigated the impact of ingesting a single bolus of concentrated nitrate-rich beetroot juice ( 140 ml , ~8.7 mmol NO3- ) on subsequent 1-hr time-trial performance in well-trained cyclists . METHODS Using a double-blind , repeated- measures crossover design ( 1-wk washout period ) , 20 trained male cyclists ( 26 ± 1 yr , VO(2peak ) 60 ± 1 ml · kg(-1 ) · min(-1 ) , Wmax 398 ± 7.7 W )  ingested 140 ml of concentrated beetroot juice ( 8.7 mmol NO3- ; BEET ) or a placebo ( nitrate-depleted beetroot juice ; PLAC ) with breakfast 2.5 hr before an ~1-hr cycling time trial ( 1,073 ± 21 kJ ) . Resting blood sample s were collected every 30 min after BEET or PLAC ingestion and immediately after the time trial . RESULTS Plasma nitrite concentration was higher in BEET than PLAC before the onset of the time trial ( 532 ± 32 vs. 271 ± 13 nM , respectively ; p < .001 ) , but subsequent time-trial performance ( 65.5 ± 1.1 vs. 65 ± 1.1 s ) , power output ( 275 ± 7 vs. 278 ± 7 W ) , and heart rate ( 170 ± 2 vs. 170 ± 2 beats/min ) did not differ between BEET and PLAC treatments ( all p > .05 ) . CONCLUSION Ingestion of a single bolus of concentrated ( 140 ml ) beetroot juice ( 8.7 mmol NO3- ) does not improve subsequent 1-hr time-trial performance in well-trained cyclists Background While it is well established that dietary nitrate reduces the metabolic cost of exercise , recent evidence suggests this effect is maintained 24 h following the final nitrate dose when plasma nitrite levels have returned to baseline . In addition , acute dietary nitrate was recently reported to enhance peak power production . Our purpose was to examine whether chronic dietary nitrate supplementation enhanced peak power 24 h following the final dose and if this impacted performance in a heavily power-dependent sport . Methods In a double-blind , r and omized , crossover design , maximal aerobic capacity , body composition , strength , maximal power ( 30 s Wingate ) , endurance ( 2 km rowing time trial ) , and CrossFit performance ( Grace protocol ) were assessed before and after six days of supplementation with nitrate ( NO ) ( 8 mmol·potassium nitrate·d−1 ) or a non-caloric placebo ( PL ) . A 10-day washout period divided treatment conditions . Paired t-tests were utilized to assess changes over time and to compare changes between treatments . Results Peak Wingate power increased significantly over time with NO ( 889.17 ± 179.69 W to 948.08 ± 186.80 W ; p = 0.01 ) but not PL ( 898.08 ± 183.24 W to 905.00 ± 157.23 W ; p = 0.75 ) . However , CrossFit performance was unchanged , and there were no changes in any other performance parameters . Conclusion Consuming dietary nitrate in the potassium nitrate salt form improved peak power during a Wingate test , but did not improve elements of strength or endurance in male CrossFit athletes Recent studies have suggested that dietary inorganic nitrate ( NO3− ) supplementation may improve muscle efficiency and endurance exercise tolerance but possible effects during team sport-specific intense intermittent exercise have not been examined . We hypothesized that NO3− supplementation would enhance high-intensity intermittent exercise performance . Fourteen male recreational team-sport players were assigned in a double-blind , r and omized , crossover design to consume 490 mL of concentrated , nitrate-rich beetroot juice ( BR ) and nitrate-depleted placebo juice ( PL ) over ~30 h preceding the completion of a Yo – Yo intermittent recovery level 1 test ( Yo – Yo IR1 ) . Resting plasma nitrite concentration ( [ NO2− ] ) was ~400 % greater in BR compared to PL . Plasma [ NO2− ] declined by 20 % in PL ( P < 0.05 ) and by 54 % in BR ( P < 0.05 ) from pre-exercise to end-exercise . Performance in the Yo – Yo IR1 was 4.2 % greater ( P < 0.05 ) with BR ( 1,704 ± 304 m ) compared to PL ( 1,636 ± 288 m ) . Blood [ lactate ] was not different between BR and PL , but the mean blood [ glucose ] was lower ( 3.8 ± 0.8 vs. 4.2 ± 1.1 mM , P < 0.05 ) and the rise in plasma [ K+ ] tended to be reduced in BR compared to PL ( P = 0.08 ) . These findings suggest that NO3− supplementation may promote NO production via the nitrate-nitrite-NO pathway and enhance Yo – Yo IR1 test performance , perhaps by facilitating greater muscle glucose uptake or by better maintaining muscle excitability . Dietary NO3− supplementation improves performance during intense intermittent exercise and may be a useful ergogenic aid for team sports players Nitric oxide ( NO ) has been demonstrated to enhance the maximal shortening velocity and maximal power of rodent muscle . Dietary nitrate ( NO3(- ) ) intake has been demonstrated to increase NO bioavailability in humans . We therefore hypothesized that acute dietary NO3(- ) intake ( in the form of a concentrated beetroot juice ( BRJ ) supplement ) would improve muscle speed and power in humans . To test this hypothesis , healthy men and women ( n = 12 ; age = 22 - 50 y ) were studied using a r and omized , double-blind , placebo-controlled crossover design . After an overnight fast , subjects ingested 140 mL of BRJ either containing or devoid of 11.2 mmol of NO3(- ) . After 2 h , knee extensor contractile function was assessed using a Biodex 4 isokinetic dynamometer . Breath NO levels were also measured periodically using a Niox Mino analyzer as a biomarker of whole-body NO production . No significant changes in breath NO were observed in the placebo trial , whereas breath NO rose by 61 % ( P < 0.001 ; effect 
    Output:
    
Thus , the present study indicates that dietary NO3 - supplementation  improves physical performance in non-athletes , particularly during long- duration open-ended tests