***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: AIMS Flavanol-rich chocolate ( FRC ) is beneficial for vascular and platelet function by increasing nitric oxide bioavailability and decreasing oxidative stress . Congestive heart failure ( CHF ) is characterized by impaired endothelial and increased platelet reactivity . As statins are ineffective in CHF , alternative therapies are a clinical need . We therefore investigated whether FRC might improve cardiovascular function in patients with CHF . METHODS AND RESULTS Twenty patients with CHF were enrolled in a double-blind , r and omized placebo-controlled trial , comparing the effect of commercially available FRC with cocoa-liquor-free control chocolate ( CC ) on endothelial and platelet function in the short term ( 2 h after ingestion of a chocolate bar ) and long term ( 4 weeks , two chocolate bars/day ) . Endothelial function was assessed non-invasively by flow-mediated vasodilatation of the brachial artery . Flow-mediated vasodilatation significantly improved from 4.98 ± 1.95 to 5.98 ± 2.32 % ( P = 0.045 and 0.02 for between-group changes ) 2h after intake of FRC to 6.86 ± 1.76 % after 4 weeks of daily intake ( P = 0.03 and 0.004 for between groups ) . No effect on endothelial-independent vasodilatation was observed . Platelet adhesion significantly decreased from 3.9 ± 1.3 to 3.0 ± 1.3 % ( P = 0.03 and 0.05 for between groups ) 2 h after FRC , an effect that was not sustained at 2 and 4 weeks . Cocoa-liquor-free CC had no effect , either on endothelial function or on platelet function . Blood pressure and heart rate did not change in either group . CONCLUSION Flavanol-rich chocolate acutely improves vascular function in patients with CHF . A sustained effect was seen after daily consumption over a 4-week period , even after 12 h abstinence . These beneficial effects were paralleled by an inhibition of platelet function in the presence of FRC only Background Dark chocolate ( DC ) is abundant in flavanols which have been reported to increase the bioavailability and bioactivity of nitric oxide ( NO ) . Increasing NO bioavailability has often demonstrated reduced oxygen cost and performance enhancement during submaximal exercise . Methods Nine moderately-trained male participants volunteered to undertake baseline ( BL ) measurements that comprised a cycle V.O2max$$ \overset{.}{V}{O}_{2 max } $ $ test followed by cycling at 80 % of their established gas exchange threshold ( GET ) for 20-min and then immediately followed by a two-minute time-trial ( TT ) . Using a r and omised crossover design participants performed two further trials , two weeks apart , with either 40 g of DC or white chocolate ( WC ) being consumed daily . Oxygen consumption , RER , heart rate and blood lactate ( BLa ) were measured during each trial . Results  DC consumption increased GET and TT performance compared to both BL and WC ( P < 0.05 ) .  DC consumption increased V.O2max$$ \overset{.}{V}{O}_{2 max } $ $ by 6 % compared to BL ( P < 0.05 ) , but did not reach statistical significance compared to WC . There were no differences in the moderate-intensity cycling for V.O2$$ \overset{.}{V}{O}_2 $ $ , RER , BLa and heart rate between conditions , although , V.O2$$ \overset{.}{V}{O}_2 $ $ and RER exhibited consistently lower trends following DC consumption compared to BL and WC , these did not reach statistical significance . Conclusion Chronic supplementation with DC result ed in a higher GET and enhanced TT performance . Consequently , ingestion of DC reduced the oxygen cost of moderate intensity exercise and may be an effective ergogenic aid for short- duration moderate intensity exercise The consumption of a diet rich in certain flavonoids , including the flavanol sub-class , has been associated with a reduced risk for vascular disease . We evaluated the effects of the regular consumption ( 14 d ) of a flavanol-containing milk chocolate ( FCMC ) or cocoa butter chocolate ( CBC ) on variables related to vascular disease risk , oxidative stress and physical activity . Twenty-eight free-living , young ( 18–20 years old ) male soccer players consumed daily 105 g of FCMC ( 168 mg of flavanols ) or CBC ( < 5 mg of flavanols ) , as part of their normal diet . The consumption of FCMC was significantly associated with a decrease in diastolic blood pressure ( -5 mm Hg ) , mean blood pressure ( -5 mm Hg ) , plasma cholesterol ( -11 % ) , LDL-cholesterol ( -15 % ) , malondialdehyde ( -12 % ) , urate ( -11 % ) and lactate dehydrogenase ( LDH ) activity ( -11 % ) , and an increase in vitamin E/cholesterol ( + 12 % ) . No relevant changes in these variables were associated with CBC consumption . No changes in the plasma levels of (-)-epicatechin were observed following analysis of fasting blood sample s. In conclusion , FCMC consumption was associated with changes in several variables often associated with cardiovascular health and oxidant stress . The presence of significant quantities of flavanols in FCMC is likely to have been one of the contributing factors to these results Impaired endothelial vasodilatation may contribute to the exaggerated blood pressure ( BP ) responses to exercise in individuals who are overweight/obese . The present study investigated whether consumption of cocoa flavanols , which improve endothelium-dependent flow-mediated dilatation ( FMD ) , can modify BP responsiveness to exercise . Twenty-one volunteers ( eight females and thirteen males , 54.9 ( se 2.2 ) years , BMI 31.6 ( se 0.8 ) kg/m2 , systolic BP 134 ( se 2 ) mmHg , diastolic BP ( DBP ) 87 ( se 2 ) mmHg ) were r and omised to consume single servings of either a high-flavanol ( HF , 701 mg ) or a low-flavanol ( LF , 22 mg ) cocoa beverage in a double-blind , cross-over design with 3 - 7-d washout between treatments . Two hours after cocoa consumption , FMD was measured , followed by continuous beat-to-beat assessment ( Finapres ) of BP before and during 10 min of cycling at 75 % of age-predicted maximum heart rate . Averaged data from two assessment s on each type of beverage were compared by analysis of covariance using pre-exercise BP as the covariate . Pre-exercise BP was similar after taking LF and HF ( 153 ( se 3)/88 ( se 3 ) v. 153 ( se 4)/87 ( se 2 ) mmHg , respectively , P>0.05 ) . However , the BP response to exercise ( area under BP curve ) was attenuated by HF compared with LF . BP increases were 68 % lower for DBP ( P = 0.03 ) and 14 % lower for mean BP ( P = 0.05 ) . FMD measurements were higher after taking HF than after taking LF ( 6.1 ( se 0.6 ) % v. 3.4 ( se 0.5 ) % , P < 0.001 ) . By facilitating vasodilation and attenuating exercise-induced increases in BP , cocoa flavanols may decrease cardiovascular risk and enhance the cardiovascular benefits of moderate intensity exercise in at-risk individuals Dietary flavanols have been associated with reduced oxidative stress , however their efficacy in promoting recovery after exercise induced muscle damage is unclear . This study examined the effectiveness of acute consumption of cocoa-flavanols on indices of muscle recovery including : subsequent exercise performance , creatine kinase , muscle tenderness , force , and self-perceived muscle soreness .  Eight endurance-trained athletes ( VO2max 64.4 ± 7.6 mL/kg/min ) completed a downhill running protocol to induce muscle soreness , and 48-h later completed a 5-K ( kilometer ) time trial . Muscle recovery measurements were taken at PRE , 24 h-POST , 48 h-POST , and POST-5 K . Participants consumed 1.0 g of carbohydrate per kilogram of body weight of a r and omly assigned beverage ( CHOC : 0 mg flavanols vs. CocoaCHOC : 350 mg flavanols per serving ) immediately after the downhill run and again 2 h later . The same protocol was repeated three weeks later with the other beverage . An ANOVA revealed no significant difference ( p = 0.97 ) between trials for 5 K completion time  ( CHOC 1198.3 ± 160.6 s , CocoaCHOC 1195.5 ± 148.8 s ) . No significant difference was found for creatine kinase ( CK ) levels ( p = 0.31 ) , or muscle soreness ( p = 0.21 ) between groups over time . These findings suggest that the acute addition of cocoa flavanols to low-fat chocolate milk offer no additional recovery benefits This study investigated the effects of regular consumption of dark chocolate ( DC ) , rich in cocoa polyphenols , on plasma metabolites , hormones , and markers of oxidative stress after prolonged exhaustive exercise . Twenty active men cycled at 60 % maximal oxygen uptake ( VO2max ) for 1.5 hr , with the intensity increased to 90 % VO2max for a 30-s period every 10 min , followed by a ride to exhaustion at 90 % VO2max . In the 2 wk before exercise participants consumed 40 g of DC or an isocarbohydrate-fat control cocoa liquor-free chocolate ( CON ) twice daily and once 2 hr before exercise in a r and omized , counterbalanced , crossover design . Venous blood sample s were taken immediately before exercise , postexercise ( fixed duration ) , postexhaustion , and after 1 hr of recovery . F2-isoprostanes were significantly lower ( post hoc tests : p < .001 ) at exhaustion and after 1 hr of recovery with DC . Oxidized low-density lipoproteins were significantly lower with DC ( p < .001 ) both before and after exercise and at exhaustion . DC was also associated with ~21 % greater rises in free fatty acids during exercise ( main effect : p < .05 ) . Changes in circulating glucose , insulin , glucagon , cortisol , and interleukin (IL)-6 , IL-10 , and IL-1ra were unaffected by treatment . Time to exhaustion at 90 % VO2max was not significantly different between trials ( 398 ± 204 and 374 ± 194 s for DC and CON , respectively ) . These results suggest that regular DC intake is associated with reduced oxidative-stress markers and increased mobilization of free fatty acids after exercise but has no observed effect on exercise performance OBJECTIVES This study was design ed to assess the effect of flavanol-rich food on the circulating pool of bioactive nitric oxide ( NO ) and endothelial dysfunction in smokers . BACKGROUND Studies suggest that smoking-related vascular disease is caused by impaired NO synthesis and that diets rich in flavanols can increase bioactive NO in plasma . METHODS In smokers ( n = 11 ) , the effects of flavanol-rich cocoa on circulating NO species in plasma ( RXNO ) measured by reductive gas-phase chemiluminescence and endothelial function as assessed by flow-mediated dilation ( FMD ) were characterized in a dose-finding study orally administering cocoa containing 88 to 370 mg flavanols and in a r and omized double-blind crossover study using 100 ml cocoa drink with high ( 176 to 185 mg ) or low ( < 11 mg ) flavanol content on two separate days . In addition to cocoa drink , ascorbic acid and NO-synthase inhibitor L-NMMA ( n = 4 ) were applied . RESULTS There were significant increases in RXNO ( 21 + /- 3 nmol/l to 29 + /- 5 nmol/l ) and FMD ( 4.5 + /- 0.8 % to 6.9 + /- 0.9 % , each p < 0.05 ) at 2 h after ingestion of 176 to 185 mg flavanols , a dose potentially exerting maximal effects . These changes correlated with increases in flavanol metabolites . Cocoa-associated increases in RXNO and FMD were reversed by L-NMMA . Ascorbic acid had no effect . CONCLUSIONS The circulating pool of bioactive NO and endothelium-dependent vasodilation is acutely increased in smokers following the oral ingestion of a flavanol-rich cocoa drink . The increase in circulating NO pool may contribute to beneficial vascular health effects of flavanol-rich food Acute exercise-induced improvements in cognitive function are accompanied by increased ( cerebral ) blood flow and increased brain-derived neurotrophic factor ( BDNF ) levels . Acute cocoa flavanol ( CF ) intake may improve cognitive function , cerebral blood flow ( in humans ) , and BNDF levels ( in animals ) . This study investigated ( i ) the effect of CF intake in combination with exercise on cognitive function and ( ii ) cerebral hemodynamics and 
    Output:
    
Results Acute , sub-chronic ( 2 weeks ) and chronic ( 3 months ) CF intake  reduced exercise-induced oxidative stress .
Evidence on the effect of CF on exercise-induced inflammation and platelet activation was scarce .
Acute CF intake reduced and tempered the exercise-induced increase in blood pressure in obese participants .
Acute and sub-chronic CF intake altered fat and carbohydrate metabolism during exercise .
Acute and sub-chronic CF intake did not have ergogenic effects in athletes , while chronic CF intake improved mitochondrial efficiency in untrained participants .
While combining sub-chronic CF intake and exercise training improved cardiovascular risk factors and vascular function , evidence on the synergistic effects of CF and exercise training on oxidative stress , inflammation , and fat and glucose metabolism was lacking .
Conclusion CF intake may improve vascular function , reduce exercise-induced oxidative stress , and alter fat and carbohydrate utilization during exercise , but without affecting exercise performance .