scholarly journals The influence of alkalosis on repeated high-intensity exercise performance and acid–base balance recovery in acute moderate hypoxic conditions

2018 ◽  
Vol 118 (12) ◽  
pp. 2489-2498 ◽  
Author(s):  
Lewis Anthony Gough ◽  
Danny Brown ◽  
Sanjoy K. Deb ◽  
S. Andy Sparks ◽  
Lars R. McNaughton
2014 ◽  
Vol 116 (5) ◽  
pp. 553-559 ◽  
Author(s):  
Audrey Baguet ◽  
Inge Everaert ◽  
Benito Yard ◽  
Verena Peters ◽  
Johannes Zschocke ◽  
...  

Given the ergogenic properties of β-alanyl-L-histidine (carnosine) in skeletal muscle, it can be hypothesized that elevated levels of circulating carnosine could equally be advantageous for high-intensity exercises. Serum carnosinase (CN1), the enzyme hydrolyzing the dipeptide, is highly active in the human circulation. Consequently, dietary intake of carnosine usually results in rapid degradation upon absorption, yet this is less pronounced in subjects with low CN1 activity. Therefore, acute carnosine supplementation before high-intensity exercise could be ergogenic in these subjects. In a cross-sectional study, we determined plasma CN1 activity and content in 235 subjects, including 154 untrained controls and 45 explosive and 36 middle- to long-distance elite athletes. In a subsequent double-blind, placebo-controlled, crossover study, 12 men performed a cycling capacity test at 110% maximal power output (CCT 110%) following acute carnosine (20 mg/kg body wt) or placebo supplementation. Blood samples were collected to measure CN1 content, carnosine, and acid-base balance. Both male and female explosive athletes had significantly lower CN1 activity (14% and 21% lower, respectively) and content (30% and 33% lower, respectively) than controls. Acute carnosine supplementation resulted only in three subjects in carnosinemia. The CCT 110% performance was not improved after carnosine supplementation, even when accounting for low/high CN1 content. No differences were found in acid-base balance, except for elevated resting bicarbonate following carnosine supplementation and in low CN1 subjects. In conclusion, explosive athletes have lower serum CN1 activity and content compared with untrained controls, possibly resulting from genetic selection. Acute carnosine supplementation does not improve high-intensity performance.


1989 ◽  
Vol 58 (8) ◽  
pp. 858-864 ◽  
Author(s):  
John M. Kowalchuk ◽  
Stephen A. Maltais ◽  
Keiji Yamaji ◽  
Richard L. Hughson

2017 ◽  
Vol 27 (5) ◽  
pp. 429-438 ◽  
Author(s):  
Lewis A. Gough ◽  
Steven Rimmer ◽  
Callum J. Osler ◽  
Matthew F. Higgins

This study evaluated the ingestion of sodium bicarbonate (NaHCO3) on postexercise acid-base balance recovery kinetics and subsequent high-intensity cycling time to exhaustion. In a counterbalanced, crossover design, nine healthy and active males (age: 23 ± 2 years, height: 179 ± 5 cm, body mass: 74 ± 9 kg, peak mean minute power (Wpeak) 256 ± 45 W, peak oxygen uptake (V̇O2peak) 46 ± 8 ml.kg-1.min-1) performed a graded incremental exercise test, two familiarization and two experimental trials. Experimental trials consisted of cycling to volitional exhaustion (TLIM1) at 100% WPEAK on two occasions (TLIM1 and TLIM2) interspersed by a 90 min passive recovery period. Using a double-blind approach, 30 min into a 90 min recovery period participants ingested either 0.3 g.kg-1 body mass sodium bicarbonate (NaHCO3) or a placebo (PLA) containing 0.1 g.kg-1 body mass sodium chloride (NaCl) mixed with 4 ml.kg-1 tap water and 1 ml.kg-1 orange squash. The mean differences between TLIM2 and TLIM1 was larger for PLA compared with NaHCO3 (-53 ± 53 vs. -20 ± 48 s; p = .008, d = 0.7, CI =-0.3, 1.6), indicating superior subsequent exercise time to exhaustion following NaHCO3. Blood lactate [Bla-] was similar between treatments post TLIM1, but greater for NaHCO3 post TLIM2 and 5 min post TLIM2. Ingestion of NaHCO3 induced marked increases (p < .01) in both blood pH (+0.07 ± 0.02, d = 2.6, CI = 1.2, 3.7) and bicarbonate ion concentration [HCO3-] (+6.8 ± 1.6 mmo.l-1, d = 3.4, CI = 1.8, 4.7) compared with the PLA treatment, before TLIM2. It is likely both the acceleration of recovery, and the marked increases of acid-base after TLIM1 contributed to greater TLIM2 performance compared with the PLA condition.


2005 ◽  
Vol 2 (2) ◽  
pp. 119-127 ◽  
Author(s):  
Amanda Waller ◽  
Michael I Lindinger

AbstractThe present study used the physicochemical approach to characterize the changes in acid–base status that occur in Standardbred racehorses during recovery from high-intensity exercise. Jugular venous blood was sampled from nine Standardbreds in racing condition, at rest and for 2 h following a high-intensity training workout. Plasma [H+] increased from 39.1±1.0 neq l−1 at rest to 44.8±2.7 neq l−1 at 1 min of recovery. A decreased strong ion difference ([SID]) was the primary contributor to the increased [H+] immediately at the end of exercise, while increased plasma weak ion concentration ([Atot]) was a minor contributor to the acidosis. A decreased partial pressure of carbon dioxide (PCO2) at 1 min of recovery had a slight alkalinizing effect. The decreased [SID] at 1 min of recovery was a result of a 15.1±3.1 meq l−1 increase in [lactate−], as [Na+] and [K+] were also increased by 6.5±0.7 and 1.14±0.06 meq l−1, respectively, at 1 min of recovery. It is concluded that high-intensity exercise and recovery is associated with significant changes in acid–base balance, and that full recovery of many parameters that determine acid–base status requires 60–120 min.


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