Changes in blood ammonia, lactate and amino acids in relation to workload during bicycle ergometer exercise in man

Babij, Philip; Matthews, Slade; Rennie, M. J.

doi:10.1007/bf00423246

Cited by 116 publications

(58 citation statements)

References 13 publications

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“…Tables 2 and 3 show mean¡SD plasma ammonia and blood lactate responses to incremental cycle exercise. Resting plasma ammonia concentrations were similar for COPD and similaraged subjects and within published ranges [7,9,24]. Plasma ammonia concentration increased during exercise in subjects with COPD (p,0.001) and similar-aged subjects (p,0.001) and continued to increase at 2 min after exercise, before declining towards baseline at 5 min after exercise.…”

Section: Incremental Exercisesupporting

confidence: 72%

The plasma ammonia response to cycle exercise in COPD

Calvert¹,

Singh²,

Greenhaff³

et al. 2007

Eur Respir J

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The plasma ammonia response to exercise in chronic obstructive pulmonary disease (COPD) was examined and the relationship between plasma ammonia concentration and muscle adenine nucleotide metabolism was explored.In total, 25 stable COPD patients and 13 similar-aged controls underwent incremental and constant-work rate cycle exercise tests. Arterialised venous blood was sampled at rest, at 1-min intervals during exercise and f5 min after exercise for ammonia and lactate concentration.Peak incremental work rate was significantly less in COPD subjects (67¡21 W) than similar-aged controls (156¡46 W). In COPD and control subjects, plasma ammonia concentration increased during incremental exercise until 2 min post-exercise and then declined by 5 min post-exercise. However, two distinct patterns were seen in COPD subjects. In one group (n516), ammonia increased (42.8¡3.3 mmol?L ). In the second COPD group (n59), no ammonia increase was observed despite a similar lactate increase. Ammonia change with incremental and constant-work rate exercise strongly correlated in COPD subjects. Plasma ammonia increase correlated with muscle inosine-59-monophosphate formation after constant-work rate exercise.Plasma ammonia concentration increases during incremental and constant-work rate cycle exercise in chronic obstructive pulmonary disease subjects at lower absolute work rates compared with similar-aged controls. The plasma ammonia response may provide useful information about adenine nucleotide metabolism and, therefore, muscle fatigue during exercise in patients with chronic obstructive pulmonary disease.

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Section: Incremental Exercisesupporting

confidence: 72%

The plasma ammonia response to cycle exercise in COPD

Calvert¹,

Singh²,

Greenhaff³

et al. 2007

Eur Respir J

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“…Ammonia is a product of adenine nucleotide deamination, which occurs during intense exercise when muscle ATP resynthesis rates cannot meet demand. Blood ammonia accumulation has been shown to occur during intense exercise in healthy humans (19,20), and we have recently confirmed that this also occurs during maximal incremental exercise in patients with COPD (17).…”

Section: Discussionsupporting

confidence: 68%

Dichloroacetate Enhances Performance and Reduces Blood Lactate during Maximal Cycle Exercise in Chronic Obstructive Pulmonary Disease

Calvert¹,

Shelley²,

Singh³

et al. 2008

Am J Respir Crit Care Med

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Rationale: Impaired skeletal muscle function contributes to exercise limitation in patients with chronic obstructive pulmonary disease (COPD). This is characterized by reduced mitochondrial adenosine triphosphate generation, and greater reliance on nonmitochondrial energy production. Dichloroacetate (DCA) infusion activates muscle pyruvate dehydrogenase complex (PDC) at rest, reducing inertia in mitochondrial energy delivery at the onset of exercise and diminishing anaerobic energy production. Objectives: This study aimed to determine whether DCA infusion enhanced mitochondrial energy delivery during symptom-limited maximal exercise, thereby reducing exercise-induced lactate and ammonia accumulation and, consequently, improving exercise performance in patients with COPD. Methods: A randomized, double-blind crossover design was used. Eighteen subjects with COPD performed maximal cycle exercise after an intravenous infusion of DCA (50 mg/kg body mass) or saline (control). Exercise work output was determined, and blood lactate and ammonia concentrations were measured at rest, 1 and 2 minutes of exercise, peak exercise, and 2 minutes postexercise. Measurements and Main Results: DCA infusion reduced peak blood lactate concentration by 20% (mean [SE]; difference, 0.48 [0.11] mmol/L, P , 0.001) and peak blood ammonia concentration by 15% (mean [SE]; difference, 14.2 [2.9] mmol/L, P , 0.001] compared with control. After DCA, peak exercise workload improved significantly by a mean (SE) of 8 (1) W (P , 0.001) and peak oxygen consumption by 1.2 (0.5) ml/kg/minute (P 5 0.03) compared with control. Conclusions: We have shown that a pharmacologic intervention known to activate muscle PDC can reduce blood lactate and ammonia accumulation during exercise and improve maximal exercise performance in subjects with COPD. Skeletal muscle PDC activation may be a target for pharmacologic intervention in the management of exercise intolerance in COPD.

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“…In fact it is well documented that, at least with endurance exercise, absolute oxidation of the amino acid leucine increases (4,31,45,67,69,78,92). This effect appears to be greatest at high exercise intensities (4,69,78,92) and in trained individuals (23, 49). Further, the magnitude of this response is substantial and under prolonged endurance exercise conditions can approach daily requirements (31).…”

Section: Possibilitymentioning

confidence: 99%

Protein and Amino Acid Needs of the Strength Athlete

Lemon

1991

International Journal of Sport Nutrition

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The debate regarding optimal proteinlamino acid needs of strength athletes is an old one. Recent evidence indicates that actual requirements are higher than those of more sedentary individuals, although this is not widely recognized. Some data even suggest that high proteinlamino acid diets can enhance the development of muscle mass and strength when combined with heavy resistance exercise training. Novices may have higher needs than experienced strength athletes, and substantial interindividual variability exists. Perhaps the most important single factor determining absolute proteinlamino acid need is the adequacy of energy intake. Present data indicate that strength athletes should consume approximately 12-15% of their daily total energy intake as protein, or about 1.5-2.0 g proteinlkg*d-' (approximately 188-250% of the U.S. recommended dietary allowance). Although routinely consumed by many strength athletes, higher protein intakes have not been shown to be consistently effective and may even be associated with some health risks.Although for most of the 20th century nutritionists have generally believed that proteinlamino acid need is not substantially affected by strength training (87), many athletes, especially body builders, have routinely consumed very high protein diets (41,60). Apparently these individuals think such diets enhance performance, but their opinion is based primarily on hearsay or uncontrolled self-experimentation and therefore lacks the necessary objectivity to convince scientists. However, recent results from several laboratories suggest that the issue of whether such high proteinlamino acid diets are beneficial to strength athletes rnay need to be readdressed (66). This paper reviews new information relative to the previous literature and discusses the potential benefits of protein1 amino acid supplementation for the strength athlete. Importance of ProteinClearly, protein is an essential nutrient for all living organisms. With the exception of water, it is the largest component in our bodies and represents about 15 % of body weight. There are many proteins but each is made up of about 20 amino Peter W.R. Lemon is with the Applied

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Changes in blood ammonia, lactate and amino acids in relation to workload during bicycle ergometer exercise in man

Cited by 116 publications

References 13 publications

The plasma ammonia response to cycle exercise in COPD

The plasma ammonia response to cycle exercise in COPD

Dichloroacetate Enhances Performance and Reduces Blood Lactate during Maximal Cycle Exercise in Chronic Obstructive Pulmonary Disease

Protein and Amino Acid Needs of the Strength Athlete

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