Elevated muscle acidity and energy production during exhaustive exercise in humans

Bangsbo, Jens; Graham, T. E.; Johansen, Lykke; Strange, S.; Christensen, Carol M.; Saltin, Bengt

doi:10.1152/ajpregu.1992.263.4.r891

Cited by 50 publications

(72 citation statements)

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“…The results also offered no evidence that low pH i accelerates muscle fatigue by decreasing glycolysis. Similarly, in humans, glycolysis and glycogenolysis are not inhibited by the pH i decreases occurring in exhaustive exercise (29,30,194), and studies with electrical stimulation in humans have shown that even though glycolysis and glycogenolysis are reduced somewhat when pH i falls from 6.7 to 6.45, significant activity still remains (415).…”

Section: Effects Of Low Ph On the Rate Of Fatiguementioning

confidence: 97%

Skeletal Muscle Fatigue: Cellular Mechanisms

Allen¹,

Lamb²,

Westerblad³

2008

Physiological Reviews

1,895

1,876

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Repeated, intense use of muscles leads to a decline in performance known as muscle fatigue. Many muscle properties change during fatigue including the action potential, extracellular and intracellular ions, and many intracellular metabolites. A range of mechanisms have been identified that contribute to the decline of performance. The traditional explanation, accumulation of intracellular lactate and hydrogen ions causing impaired function of the contractile proteins, is probably of limited importance in mammals. Alternative explanations that will be considered are the effects of ionic changes on the action potential, failure of SR Ca2+ release by various mechanisms, and the effects of reactive oxygen species. Many different activities lead to fatigue, and an important challenge is to identify the various mechanisms that contribute under different circumstances. Most of the mechanistic studies of fatigue are on isolated animal tissues, and another major challenge is to use the knowledge generated in these studies to identify the mechanisms of fatigue in intact animals and particularly in human diseases.

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Section: Effects Of Low Ph On the Rate Of Fatiguementioning

confidence: 97%

Skeletal Muscle Fatigue: Cellular Mechanisms

Allen¹,

Lamb²,

Westerblad³

2008

Physiological Reviews

1,895

1,876

View full text Add to dashboard Cite

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“…The concurrent accumulation of potassium in the muscle interstitium (21) has been suggested to be one cause of fatigue during intense exercise in humans (10). This hypothesis is supported by the finding of the same [K ϩ ] v at exhaustion when subjects performed two exhaustive exercise bouts on the same day, even though time to fatigue was different (3,4). Recently, Juel et al (21) studied interstitial potassium concentrations ([K ϩ ] i ) during graded dynamic exercise in human skeletal muscle using the microdialysis technique.…”

mentioning

confidence: 85%

Muscle interstitial potassium kinetics during intense exhaustive exercise: effect of previous arm exercise

Nordsborg

Mohr²,

Pedersen³

et al. 2003

American Journal of Physiology-Regulatory, Integrative and Comp

131

142

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Interstitial K+ ([K+]i) was measured in human skeletal muscle by microdialysis during exhaustive leg exercise, with (AL) and without (L) previous intense arm exercise. In addition, the reproducibility of the [K+]i determinations was examined. Possible microdialysis-induced rupture of the sarcolemma was assessed by measurement of carnosine in the dialysate, because carnosine is only expected to be found intracellularly. Changes in [K+]i could be reproduced, when exhaustive leg exercise was performed on two different days, with a between-day difference of ∼0.5 mM at rest and 1.5 mM at exhaustion. The time to exhaustion was shorter in AL than in L (2.7 ± 0.3 vs. 4.0 ± 0.3 min; P < 0.05). Furthermore, [K+]i was higher from 0 to 1.5 min of the intense leg exercise period in AL compared with L (9.2 ± 0.7 vs. 6.4 ± 0.9 mM; P < 0.001) and at exhaustion (11.9 ± 0.5 vs. 10.3 ± 0.6 mM; P < 0.05). The dialysate content of carnosine was elevated by exercise, but low-intensity exercise resulted in higher dialysate carnosine concentrations than subsequent intense exercise. Furthermore, no relationship was found between carnosine concentrations and [K+]i. Thus the present data suggest that microdialysis can be used to determine muscle [K+]i kinetics during intense exercise, when low-intensity exercise is performed before the intense exercise. The high [K+]i levels reached at exhaustion can be expected to cause fatigue, which is supported by the finding that a faster accumulation of interstitial K+, induced by prior arm exercise, was associated with a reduced time to fatigue.

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“…In human muscle, a calculation adapted from Newham et al (1995) can be used to estimate the expected value of non-Pi buering capacity to be around 35 slykes (largely due to protein). In the human quadriceps muscle studied by needle biopsy, when the eect of proton consumption by net PCr hydrolysis are taken into account, non-Pi buering capacity is about 40±45 slykes [recalculated from Bangsbo et al (1992a) and Spriet et al (1987a, b) using cell water % 0.66 l á (kg wet) A1 % 3.2 l á (kg dry) A1 (Sahlin 1978;Spriet et al 1987b)]. Estimates of b have also been obtained by magnetic resonance spectroscopy of the human forearm muscle.…”

Section: Possible Errors In the Calculationsmentioning

confidence: 99%

“…Although this depends upon the regulation of glycogenolysis and proton eux, it is substantially constrained by the creatine kinase equilibrium (Kemp et al 1996a) so that under a wide range of conditions the apparent buering capacity is fairly constant. Relative to the true buering capacity, values of 1.4±1.9 can be calculated from published end-exercise values of pH, PCr and lactate concentration (Bangsbo et al 1992a;Chasiotis et al 1987;Spriet et al 1987a, b). Very roughly, this suggests endexercise muscle lactate concentrations of 25, 20, 15, 5, and 1 mmol á l A1 in groups 1±5, respectively.…”

Section: Lactate Euxmentioning

confidence: 99%

Proton efflux in human skeletal muscle during recovery from exercise

Kemp

Thompson

Taylor

et al. 1997

European Journal of Applied Physiology

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In recovery from exercise, phosphocreatine resynthesis results in the net generation of protons, while the net efflux of protons restores pH to resting values. Because proton efflux rate declines as pH increases, it appears to have an approximately linear pH-dependence. We set out to examine this in detail using recovery data from human calf muscle. Proton efflux rates were calculated from changes in pH and phosphocreatine concentration, measured by 31P magnetic resonance spectroscopy, after incremental dynamic exercise to exhaustion. Results were collected post hoc into five groups on the basis of end-exercise pH. Proton efflux rates declined approximately exponentially with time. These were rather similar in all groups, even when pH changes were small, so that the apparent rate constant (the ratio of efflux rate to pH change) varied widely. However, all groups showed a consistent pattern of decrease with time; the halftimes of both proton efflux rate and the apparent rate constant were longer at lower pH. At each time-point, proton efflux rates showed a significant pH-dependence [slope 17 (3) mmol x l(-1) x min(-1) x pH unit(-1) at the start of recovery, mean (SEM)], but also a significant intercept at resting pH [16 (3) mmol x l(-1) x min(-1) at the start of recovery]. The intercept and the slope both decreased with time, with halftimes of 0.37 (0.06) and 1.4 (0.4) min, respectively. We conclude that over a wide range of end-exercise pH, net proton efflux during recovery comprises pH-dependent and pH-independent components, both of which decline with time. Comparison with other data in the literature suggests that lactate/proton cotransport can be only a small component of this initial recovery proton efflux.

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Elevated muscle acidity and energy production during exhaustive exercise in humans

Cited by 50 publications

References 0 publications

Skeletal Muscle Fatigue: Cellular Mechanisms

Skeletal Muscle Fatigue: Cellular Mechanisms

Muscle interstitial potassium kinetics during intense exhaustive exercise: effect of previous arm exercise

Proton efflux in human skeletal muscle during recovery from exercise

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