***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: CONTEXT Sodium bicarbonate ( NaHCO₃ ) is often ingested at a dose of 0.3 g/kg body mass ( BM ) , but ingestion protocol s are inconsistent in terms of using solution or capsules , ingestion period , combining NaHCO₃ with sodium citrate ( Na₃C₆H₅O₇ ) , and coingested food and fluid . PURPOSE To quantify the effect of ingesting 0.3 g/kg NaHCO₃ on blood pH , [ HCO₃- ] , and gastrointestinal ( GI ) symptoms over the subsequent 3 hr using a range of ingestion protocol s and , thus , to determine an optimal protocol . METHODS In a crossover design , 13 physically active subjects undertook 8 NaHCO₃ experimental ingestion protocol s and 1 placebo protocol .  Capillary blood was taken every 30 min and analyzed for pH and [ HCO₃- ] . GI symptoms were quantified every 30 min via question naire . Statistics used were pairwise comparisons between protocol s ; differences were interpreted in relation to smallest worthwhile changes for each variable . A likelihood of > 75 % was a substantial change . RESULTS [ HCO₃- ] and pH were substantially greater than in placebo for all other ingestion protocol s at almost all time points . When NaHCO3 was coingested with food , the greatest [ HCO₃- ] ( 30.9 mmol/kg ) and pH ( 7.49 ) and lowest incidence of GI symptoms were observed . The greatest incidence of GI side effects was observed 90 min after ingestion of 0.3 g/kg NaHCO₃ solution . CONCLUSIONS The changes in pH and [ HCO₃- ] for the 8 NaHCO₃-ingestion protocol s were similar , so an optimal protocol can not be recommended . However , the results suggest that NaHCO₃ coingested with a high-carbohydrate meal should be taken 120 - 150 min before exercise to induce substantial blood alkalosis and reduce GI symptoms ABSTRACT The aim of this study was to investigate the effects of sodium bicarbonate ( NaHCO3 ) on 4 km cycling time trial ( TT ) performance when individualised to a predetermined time to peak blood bicarbonate ( HCO3− ) . Eleven male trained cyclists volunteered for this study ( height 1.82 ± 0.80 m , body mass ( BM ) 86.4 ± 12.9 kg , age 32 ± 9 years , peak power output ( PPO ) 382 ± 22 W ) . Two trials were initially conducted to identify time to peak HCO3− following both 0.2 g.kg−1 BM ( SBC2 ) and 0.3 g.kg−1 BM ( SBC3 ) NaHCO3 . Thereafter , on three separate occasions using a r and omised , double-blind , crossover design , participants completed a 4 km TT following ingestion of either SBC2 , SBC3 , or a taste-matched placebo ( PLA ) containing 0.07 g.kg−1 BM sodium chloride ( NaCl ) at the predetermined individual time to peak HCO3−. Both SBC2 ( −8.3 ± 3.5 s ; p < 0.001 , d = 0.64 ) and SBC3 ( −8.6 ± 5.4 s ; p = 0.003 , d = 0.66 ) reduced the time to complete the 4 km TT , with no difference between SBC conditions ( mean difference = 0.2 ± 0.2 s ; p = 0.87 , d = 0.02 ) . These findings suggest trained cyclists may benefit from individualising NaHCO3 ingestion to time to peak HCO3− to enhance 4 km TT performance The aim of the present study was to examine the effects of sodium bicarbonate ( NaHCO3 ) administration on  lower-body , hypertrophy-type resistance exercise ( HRE )  . Using a double-blind r and omized counterbalanced design , 12 resistance-trained male participants ( mean ± SD ; age = 20.3 ± 2 years , mass = 88.3 ± 13.2 kg , height = 1.80 ± 0.07 m ) ingested 0.3 g kg−1 of NaHCO3 or placebo 60 min before initiation of an HRE regimen . The protocol employed multiple exercises : squat , leg press , and knee extension , utilizing four sets each , with 10–12 repetition-maximum loads and short rest periods between sets . Exercise performance was determined by total repetitions generated during each exercise , total accumulated repetitions , and a performance test involving a fifth set of knee extensions to failure . Arterialized capillary blood was collected via fingertip puncture at four time points and analyzed for pH , [ HCO3− ] , base excess ( BE ) , and lactate [ Lac− ] . NaHCO3 supplementation induced a significant alkaline state ( pH : NaHCO3 : 7.49 ± 0.02 , placebo : 7.42 ± 0.02 , P < 0.05 ; [ HCO3− ] : NaHCO3 : 31.50 ± 2.59 , placebo : 25.38 ± 1.78 mEq L−1 , P < 0.05 ; BE : NaHCO3 : 7.92 ± 2.57 , placebo : 1.08 ± 2.11 mEq L−1 , P < 0.05 ) . NaHCO3 administration result ed in significantly more total repetitions  than placebo ( NaHCO3 : 139.8 ± 13.2 , placebo : 134.4 ± 13.5 ) , as well as significantly greater blood [ Lac− ] after the exercise protocol ( NaHCO3 : 17.92 ± 2.08 , placebo : 15.55 ± 2.50 mM , P < 0.05 ) . These findings demonstrate ergogenic efficacy for NaHCO3 during HRE and warrant further investigation into chronic training applications Sodium bicarbonate ingestion has been shown to improve performance in single-bout , high intensity events , probably due to an increase in buffering capacity , but its influence on single-bout swimming performance has not been investigated . The effects of sodium bicarbonate supplementation on 200 m freestyle swimming performance were investigated in elite male competitors . Following a r and omised , double blind counterbalanced design , 9 swimmers completed maximal effort swims on 3 separate occasions : a control trial ( C ) ; after ingestion of sodium bicarbonate ( SB : NaHCO3 300 mg . kg ( -1 ) body mass ) ; and after ingestion of a placebo ( P : CaCO3 200 mg . kg ( -1 ) body mass ) . The SB and P agents were packed in gelatine capsules and ingested 90 - 60 min prior to each 200 m swim . Mean 200 m performance times were significantly faster for SB than C or P ( 1 : 52.2 + /- 4.7 ; 1 : 53.7 + /- 3.8 ; 1 : 54.0 + /- 3.6 min : ss ; p < 0.05 ) . Base excess , pH and blood bicarbonate were all elevated pre-exercise in the SB compared to C and P trials ( p < 0.05 ) . Post-200 m blood lactate concentrations were significantly higher following the SB trial compared with P and C ( p < 0.05 ) . It was concluded that SB supplementation can improve 200 m freestyle performance time in elite male competitors , most likely by increasing buffering capacity We tested the hypothesis that reducing hydrogen ion accumulation during training would result in greater improvements in muscle oxidative capacity and time to exhaustion ( TTE ) .  Male Wistar rats were r and omly assigned to one of three groups ( CON , PLA , and BIC ) . CON served as a sedentary control , whereas PLA ingested water and BIC ingested sodium bicarbonate 30 min prior to every training session . Training consisted of seven to twelve 2-min intervals performed five times/wk for 5 wk . Following training , TTE was significantly greater in BIC ( 81.2 + /- 24.7 min ) compared with PLA ( 53.5 + /- 30.4 min ) , and TTE for both groups was greater than CON ( 6.5 + /- 2.5 min ) . Fiber respiration was determined in the soleus ( SOL ) and extensor digitorum longus ( EDL ) , with either pyruvate ( Pyr ) or palmitoyl carnitine ( PC ) as substrates . Compared with CON ( 14.3 + /- 2.6 nmol O(2).min(-1).mg dry wt(-1 ) ) , there was a significantly greater SOL-Pyr state 3 respiration in both PLA ( 19.6 + /- 3.0 nmol O(2).min(-1).mg dry wt(-1 ) ) and BIC ( 24.4 + /- 2.8 nmol O(2).min(-1).mg dry wt(-1 ) ) , with a significantly greater value in BIC . However , state 3 respiration was significantly lower in the EDL from both trained groups compared with CON . These differences remained significant in the SOL , but not the EDL , when respiration was corrected for citrate synthase activity ( an indicator of mitochondrial mass ) . These novel findings suggest that reducing muscle hydrogen ion accumulation during running training is associated with greater improvements in both mitochondrial mass and mitochondrial respiration in the soleus PURPOSE Fifteen males were studied before , during , and in recovery from exhaustive resistance exercise  105 min after ingesting 0.3 g.kg-1 of either a placebo ( white flour ) or sodium bicarbonate ( NaHCO3 ) . METHODS The exercise consisted of five maximal sets on a leg press machine , The load was adjusted to maintain the number of repetitions per set for each subject at approximately 12 repetitions . A significant ( P < 0.05 ) increase in pH ( 7.40 to 7.47 ) , oxygenated base excess ( OxyBE ) ( -1.3 to 4.0 mEq . L-1 ) , and bicarbonate concentration ( [ HCO3- ] ) ( 22.8 to 27.4 mM ) was achieved before exercise with the ingestion of NaHCO3 . RESULTS The exercise protocol produced significant changes in acid base status consistent with metabolic acidosis for both trials ( pH sets 1 - 5 : placebo , 7.4 to 7.26 ; NaHCO3 , 7.47 to 7.33 ) , ( OxyBE sets 1 - 5 : placebo , -1.3 to -12.3 mEq . L-1 ; NaHCO3 , 4.0 to -6.9 mEq . L-1 ) and ( [ HCO3- ] sets 1 - 5 : placebo , 22.9 to 14.0 mM ; NaHCO3 , 27.4 to 17.6 mM ) . After every set ; pH , OxyBE , and [ HCO3- ] were significantly higher in the NaHCO3 trial . Blood lactate concentration ( [ La- ] ) significantly increased throughout exercise for both trials ( [ La- ] sets 1 - 5 : placebo , 4.6 to 11.3 mM ; NaHCO3 , 4.8 to 13.4 mM ) . After sets 4 and 5 , blood [ La- ] was significantly higher in the NaHCO3 trial . Bicarbonate ingestion did not improve performance ( total repetitions : NaHCO3 = 59 + /- 3 ; placebo = 60 + /- 2 ) . CONCLUSIONS This may be a result of a lower dem and on the whole body metabolic system in comparison with that for other modes of exercise in which ergogenic effects have been found Alkalosis enhances human exercise performance , and reduces K+ loss in contracting rat muscle . We investigated alkalosis effects on K+ regulation , ionic regulation and fatigue during intense exercise in nine untrained volunteers .  Concentric finger flexions were conducted at 75 % peak work rate ( 3 W ) until fatigue , under alkalosis ( Alk , NaHCO3 , 0.3 g kg(-1 ) ) and control ( Con , CaCO3 ) conditions , 1 month apart in a r and omised , double-blind , crossover design . Deep antecubital venous ( v ) and radial arterial ( a ) blood was drawn at rest , during exercise and recovery , to determine arterio-venous differences for electrolytes , fluid shifts , acid-base and gas exchange . Finger flexion exercise barely perturbed arterial plasma ions and acid-base status , but induced marked arterio-venous changes . Alk elevated [ HCO3- ] and PCO2 , and lowered [ H+ ] ( P < 0.05 ) . Time to fatigue increased substantially during Alk ( 25 + /- 8 % , P < 0.05 ) , whilst both [K+]a and [K+]v were reduced ( P < 0.01 ) and [K+]a-v during exercise tended to be greater ( P= 0.056 , n= 8) . Muscle K+ efflux at fatigue was greater in Alk ( 21.2+/- 7.6 micromol min(-1 ) , 32 + /- 7 % , P < 0.05 , n= 6 ) , but peak K+ uptake rate was elevated during recovery ( 15 + /- 7 % , P < 0.05 ) suggesting increased muscle Na+,K+-ATPase activity . Alk induced greater [Na+]a , [Cl-]v , muscle Cl- influx and muscle lactate concentration ( [ Lac- 
    Output:
    
No significant linear trends in the effects of timing of sodium bicarbonate ingestion or acute increase in blood bicarbonate concentrations on muscular endurance or muscular strength were found .
Overall , sodium bicarbonate supplementation acutely improves muscular endurance of small and large muscle groups , but no significant ergogenic effect on muscular strength was found