***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: The effects of caffeine on anaerobic exercise in young boys was investigated . Twenty-four healthy 8 - 10 year old boys participated in a r and omized double-blind , double-crossover , counter-balanced study . Each subject received the caffeinated drink ( CAF--5 mg · kg(-1 ) ) or placebo ( PL ) twice each on four separate visits . Sixty minutes following ingestion of either CAF or PL boys performed a static h and -grip test and then a Wingate test . Reliability was moderately high for the Wingate test ( R = .70 - 0.95 ) . H and -grip reliability was higher for CAF ( R = .88 ) than PL ( R = .52 ) . Mean power ( 180 ± 36 vs 173 ± 28 W ) was significantly higher ( p < .05 ) in CAF versus PL , respectively . There were no differences in peak power or static h and -grip maximal voluntary contraction with CAF . Further , peak HR ( 190 ± 10 vs 185 ± 10 beats · min(-1 ) ) was significantly higher in CAF versus PL , respectively . Thus , in this study a moderately high dose of CAF significantly increased the average power during a Wingate test , yet it does not affect peak power or static h and -grip strength PURPOSE We determined the effect of caffeine restriction and fluid manipulation in the treatment of patients with urodynamic stress incontinence and detrusor overactivity . MATERIAL S AND METHODS This was a 4-week r and omized , prospect i ve , observational crossover study in 110 women with urodynamic stress incontinence ( USI ) or idiopathic detrusor overactivity ( IDO ) to determine the effect of caffeine restriction , and of increasing and decreasing fluid intake on urinary symptoms . Data were recorded in a urinary diary for the entire study period on urgency episodes , frequency , pad weight increase , wetting episodes and quality of life . RESULTS A total of 69 women with a mean age of 54.8 years completed the study , including 39 with USI and 30 with IDO . In the IDO group decreasing fluid intake significantly decreased voiding frequency , urgency and wetting episodes with improved quality of life . In the USI group there was a significant decrease in wetting episodes when fluid intake was decreased . Changing from caffeine containing to decaffeinated drinks produced no improvement in symptoms . CONCLUSIONS Conservative and life-style interventions are first line treatments in the management of incontinence and storage lower urinary tract symptoms . This study shows that a decrease in fluid intake improves some of these symptoms in patients with USI and IDO and , therefore , it should be considered when treating such patients The purpose of this study was to assess the influence of rehydration with a caffeinated beverage during nonexercise periods on hydration status throughout consecutive practice s in the heat . Ten ( 7 women , 3 men ) partially heat- acclimated athletes ( age 24 + /-1y , body fat 19.2 + /- 2 % , weight 68.4 + /- 4.0 kg , height 170 + /- 3 cm ) completed 3 successive days of 2-a-day practice s ( 2 h/ practice , 4 h/d ) in mild heat ( WBGT = 23 C ) . The 2 trials ( double-blind , r and om , cross-over design ) included ; 1 ) caffeine ( CAF ) rehydrated with Coca-Cola and 2 ) caffeine-free ( CF ) rehydrated with Caffeine-Free Coca-Cola .  Urine and psychological measures were determined before and after each 2-h practice . A significant difference was found for urine color for the post-AM time point , F = 5.526 , P = 0.031 . No differences were found among other variables ( P > 0.05 ) . In summary , there is little evidence to suggest that the use of beverages containing caffeine during nonexercise might hinder hydration status The effect of a single oral dose of caffeine was examined in a r and omised double-blind placebo-controlled repeated- measures cross-over study . Eighteen children with AD/HD , aged between 8 and 13 years , were individually age- and gender-matched with a control group . All children participated in two sessions , one week apart . Skin conductance level ( SCL ) from a 3 min eyes-closed epoch , commencing 30 min after ingestion of caffeine or placebo , was examined . Across conditions , mean SCL was lower in the AD/HD group than controls , confirming hypoarousal in AD/HD . Caffeine produced an increase in SCL , and this increase did not differ between the groups . However , arousal increases were dose-dependent in controls , but not in AD/HD . Rather , caffeine-induced arousal increases in the AD/HD group were positively related to their hyperactivity/impulsivity levels . This suggests an anomalous arousal mechanism in AD/HD functionally related to impairment in one symptom dimension There is a belief that caffeinated drinks , such as tea , may adversely affect hydration . This was investigated in a r and omised controlled trial . Healthy resting males ( n 21 ) were recruited from the general population . Following 24 h of abstention from caffeine , alcohol and vigorous physical activity , including a 10 h overnight fast , all men underwent four separate test days in a counter-balanced order with a 5 d washout in between . The test beverages , provided at regular intervals , were 4 × 240 ml black ( i.e. regular ) tea and 6 × 240 ml black tea , providing 168 or 252 mg of caffeine . The controls were identical amounts of boiled water . The tea was prepared in a st and ardised way from tea bags and included 20 ml of semi-skimmed milk . All food taken during the 12 h intervention period was controlled , and subjects remained at rest . No other beverages were offered . Blood was sample d at 0 , 1 , 2 , 4 , 8 and 12 h , and a 24 h urine sample was collected . Outcome variables were whole blood cell count , Na , K , bicarbonate , total protein , urea , creatinine and osmolality for blood ; and total volume , colour , Na , K , creatinine and osmolality for urine . Although data for all twenty-one participants were included in the analysis ( mean age 36 years and mean BMI 25·8 kg/m(2 ) ) , nineteen men completed all conditions . Statistical analysis , using a factorial ANOVA approach within PROC MIXED , revealed no significant differences between tea and water for any of the mean blood or urine measurements . It was concluded that black tea , in the amounts studied , offered similar hydrating properties to water We compared the influence of caffeine on physiological responses to exercise between boys and men . Fifty-two participants ( 26 boys and 26 men ) participated in a double blind , r and omized , double crossover study . Each participant received the caffeinated ( 5 mg/kg ) drink ( CAF ) and placebo ( PL ) twice each on 4 separate days . One hour after drink consumption preexercise heart rate ( HR ) and blood pressure ( BP ) were measured . Then while the participants rode stationary cycle ergometers at two different exercise intensities , HR , BP , and oxygen consumption ( VO2 ) were measured . Blood pressure was not significantly affected by CAF , although on average it was always higher in boys for diastolic BP ( 3 mmHg ) and systolic BP ( 3 - 4 mmHg ) and men for diastolic BP ( 2 - 3 mmHg ) and systolic BP ( 1 - 6 mmHg ) both at rest and during exercise . HR was significantly ( p < .05 ) lower at rest , 25W and 50W in CAF versus PL in boys , with no change in adults . During exercise , VO2 and respiratory exchange ratio ( RER ) were not different in CAF versus PL in either group . In conclusion , metabolism is not affected by a moderate caffeine dose in children or adults . The same dose has a similar effect on BP in both groups . The effect on HR was different , however , with a significant ( p < .05 ) lowering in children in CAF versus PL , with no adult effects INTRODUCTION / PURPOSE This study investigated the effects of three different doses of caffeine on physiological responses to exercise in young children . METHODS Forty healthy children ( 20 boys and 20 girls ) volunteered for a r and om , double-blind , counterbalanced study where they received either placebo ( PL ) , 1 mg.kg(-1 ) ( CAF-1 ) , 3 mg.kg(-1 ) ( CAF-3 ) , or 5 mg.kg(-1 ) ( CAF-5 ) caffeine , 60 min prior to preexercise measures , followed by cycle ergometer exercise at 25 W and then 60 % VO2peak . During this time , heart rate ( HR ) , oxygen consumption ( VO2 ) , and respiratory exchange ratio ( RER ) were measured continuously , while blood pressure ( BP ) was measured every 2 min . RESULTS There were no significant gender x treatment interactions , and so the boys ' and girls ' data were combined . At preexercise , CAF-5 SBP and DBP were significantly ( P < 0.05 ) higher than PL . Both CAF-1 and CAF-3  DBP were also significantly ( P < 0.05 ) higher versus PL at preexercise . There were no treatment effects for exercise BP . At rest and during both exercise intensities , HR was significantly ( P < 0.05 ) lower in CAF-3 ( approximately 5 bpm ) and CAF-5 ( approximately 6 bpm ) versus PL . There were no significant effects of CAF on metabolism ( VO2 or RER ) except for a lower RER in CAF-1 versus CAF-5 at 60 % VO2peak . CONCLUSION Low , mild , and moderate ( 1 , 3 , and 5 mg.kg(-1 ) ) doses of caffeine have no effect on substrate use as reflected by RER . Further , caffeine intake result ed in an increase in BP and decrease in HR at preexercise and a slight decrease in HR with CAF-3 and CAF-5 versus PL during exercise Objective : To examine the effect of various combinations of beverages on hydration status in healthy free-living adult males . Methods : In a counterbalanced , crossover manner , 18 healthy adult males ages 24 to 39 , on four separate occasions , consumed water or water plus varying combinations of beverages . Clinical guidelines were used to determine the fluid allowance for each subject . The beverages were carbonated , caffeinated caloric and non-caloric colas and coffee . Ten of the 18 subjects consumed water and carbonated , non-caffeinated , citrus soft drink during a fifth trial . Body weight , urine and blood assays were measured before and after each treatment . Results : Slight body weight loss was observed on all treatments , with an average of 0.30 % for all treatments . No differences ( p>0.05 ) among treatments were found for body weight changes or any of the biochemical assays . Biochemical assays conducted on first voids and 24-hour urines included electrolytes , creatine , osmolality and specific gravity . Blood sample s were analyzed for hemoglobin , hematocrit , electrolytes , osmolality , urea nitrogen , creatinine and protein . Conclusions : This preliminary study found no significant differences in the effect of various combinations of beverages on hydration status of healthy adult males . Advising people to disregard caffeinated beverages as part of the daily fluid intake is not substantiated by the results of this study . The across-treatment weight loss observed , when combined with data on fluid-disease relationships , suggests that optimal fluid intake may be higher than common recommendations . Further research is needed to confirm these results and to explore optimal fluid intake for healthy individuals AIM : This in vitro study was to evaluate the endogenous pH , titratable acidity , total soluble solids content ( TSSC ) and nonreducing sugars of energy drinks . METHODS : Nine energy drinks ( Bad Boy Power Drink , Red Bull , Red Bull Sugar Free , Flying Horse , Burn , Night Power , Flash Power , Flying Horse Light and 220V )  were evaluated by a r and omised experiment with 3 repetitions on each sample . pH analysis performed by potentiometry and buffering capacity was assessed by dilution of each drink . Increments of 0.1 N KOH were titrated until neutrality reached . TSSC readings were performed by Brix refractometry using an Abbé refractometer . RESULTS : pH values ranged from 1.52 ( Flash Power ) to 3.20 ( Red Bull ) and all drinks showed pH 5.5 . Titratable acidity values ranged from 0.56 ( 220V ) to 1.04 ( Bad Boy Power Drink ) . Flying Horse Light presented the lowest TSSC content ( 1.66 % ) and Flying Horse presented the highest ( 12.58 % ) . Non-reducing sugars values ranged from 0.00 % ( Red Bull Sugar Free and Flying Horse Light ) to 54.33 % ( Flying Horse ) . CONCLUSION : The energy drinks evaluated have a high erosive potential , as they present low pH and a high non-reducing sugar content OBJECTIVE The purpose of this investigation was to study the acute effects of caffeine on learning , performance , and anxiety in normal prepubertal children . METHOD Twenty-one children were evaluated in a double-blind , placebo-controlled crossover design . Subjects were studied during four sessions , 1 week apart , under the following conditions : baseline 
    Output:
    
High caffeine intakes ( e.g. > 5 mg kg(-1 ) body weight day(-1 ) ) were associated with an increased risk of anxiety and withdrawal symptoms .
However , smaller amounts were not linked with such effects and may benefit cognitive function and sports performance based on adult studies .
Lower contributors of caffeine , such as tea , may be more appropriate for children because they contribute to daily fluid intakes and provide flavonoids .
By contrast , caffeinated soft drinks may be less suitable options for children as a result of their acidity , higher caffeine content , presence of added sugar ( in some cases ) and absence of bioactive compounds .