Oxygen consumption is increased relative to work rate in patients with McArdle's disease

O'Dochartaigh, Conor; Ong, Hean‐Yee; Lovell, S; Riley, M.; Patterson, Victor; Nicholls, D. P.

doi:10.1111/j.1365-2362.2004.01423.x

Cited by 14 publications

(28 citation statements)

References 42 publications

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“…They concluded that the low RER was due to the lack of release of CO 2 stores due to the absence of lactate acidosis impairment of mitochondrial respiration. Similar results have been reported in groups of McArdle's patients, such that the increased ratio of O 2 consumption to CO 2 production showed the inverse of an anaerobic threshold (105,220,226). These results are similar to those seen in subjects whose leg cycling muscles have been reduced of glycogen prior to performing a progressive exercise test.…”

Section: Menopausesupporting

confidence: 90%

“…The increased VE versus VCO 2 slope, as well as an increased VE and VE/VCO 2 slope at peak exercise in McArdle's patients led O'Dochartaigh et al (220) to suggest that the catecholamine excess may partially explain their increased ventilatory response to exercise, in agreement with a previous suggestion arising from research in normal individuals (349). The VE/VCO 2 slope provides an indication of the sensitivity of chemoreceptors drive to ventilate.…”

Section: Menopausementioning

confidence: 73%

“…TheirVo 2 max is usually about 1/3 that of control subjects, with reduced muscle O 2 extraction and increased ammonia production in contracting muscle (220,318). Furthermore, contracting muscle experiences a reduced blood flow and perhaps a partial ischemia despite markedly enhanced hyperventilation, heart rate, and catecholamine responses compared with normal controls (220,319).…”

Section: Menopausementioning

confidence: 96%

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Effects of Gas Exchange on Acid‐Base Balance

Lindinger

Heigenhauser

2012

Comprehensive Physiology

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This paper describes the interactions between ventilation and acid-base balance under a variety of conditions including rest, exercise, altitude, pregnancy, and various muscle, respiratory, cardiac, and renal pathologies. We introduce the physicochemical approach to assessing acid-base status and demonstrate how this approach can be used to quantify the origins of acid-base disorders using examples from the literature. The relationships between chemoreceptor and metaboreceptor control of ventilation and acid-base balance summarized here for adults, youth, and in various pathological conditions. There is a dynamic interplay between disturbances in acid-base balance, that is, exercise, that affect ventilation as well as imposed or pathological disturbances of ventilation that affect acid-base balance. Interactions between ventilation and acid-base balance are highlighted for moderate- to high-intensity exercise, altitude, induced acidosis and alkalosis, pregnancy, obesity, and some pathological conditions. In many situations, complete acid-base data are lacking, indicating a need for further research aimed at elucidating mechanistic bases for relationships between alterations in acid-base state and the ventilatory responses.

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Section: Menopausesupporting

confidence: 90%

Section: Menopausementioning

confidence: 73%

Section: Menopausementioning

confidence: 96%

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Effects of Gas Exchange on Acid‐Base Balance

Lindinger

Heigenhauser

2012

Comprehensive Physiology

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“…This has been supported in other publications. 1,7,8 More recent literature supports the concept of there being few adverse effects during pregnancy and subsequent labour thus suggesting that labour and vaginal delivery are not precluded. 1 Perez et al and Maté-Muň oz et al report that adults with McArdle disease can re-condition their fitness with pre-exercise sucrose administration 9 and that training is possible under controlled conditions.…”

Section: Discussionmentioning

confidence: 89%

Myophosphorylase deficiency (McArdle disease) in a patient with normal pregnancy and normal pregnancy outcome

Giles

Maher

2011

Obstet Med

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Summary:McArdle disease is a rare, mostly autosomal recessive disorder of deficient myophosphorylation of glycogen in skeletal muscles. Recent knowledge regarding this condition means that women of childbearing age with McArdle disease can expect to labour normally without ill effect. We report a case of a 30-year-old woman in her first pregnancy who had an episode of exerciseinduced myoglobinuria with a significant rise in serum creatine kinase (CK) levels in early pregnancy who then laboured normally but did require a caesarean section for a malposition of the fetal head.

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“…Biochemical inefficiency may also result in peak V O 2 Ͼ peak work, such as in McArdle disease, where there is a higher V O 2 for a given amount of work, due to altered substrate utilization and a greater cardiovascular response to exercise. 29 Both mechanical and biochemical factors may explain why different levels of work are achieved for the same peak V O 2 depending on the exercise protocol. For example, total work achieved is higher with a greater work increment protocol, as seen here.…”

Section: Discussionmentioning

confidence: 99%

Assessing Maximal Exercise Capacity: Peak Work or Peak Oxygen Consumption?

Kaminsky

Knyazhitskiy²,

Sadeghi

et al. 2013

Respir Care

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BACKGROUND: Exercise capacity assessed by cardiopulmonary exercise testing is usually measured by peak oxygen consumption (V O 2 ). However, not uncommonly, patients achieve a relatively higher work load (peak work) compared to their peak V O 2 . In these situations it is difficult to know which parameter to use in assessing exercise capacity. The purpose of this study was to determine whether there are distinguishing physiological characteristics of patients with discordance between percent-of-predicted peak work versus peak V O 2 , in order to understand how to use these measurements in interpreting exercise capacity. METHODS: We conducted a retrospective study of 172 cardiopulmonary exercise tests performed at our institution between 2003 and 2010. RESULTS: The subjects in the higher peak work group demonstrated higher ventilatory efficiency (lower slope of minute ventilation to carbon dioxide production) and lung function (FEV 1 and FVC), a greater breathing reserve (higher breathing reserve, lower V E /maximal voluntary ventilation), and achieved a higher maximal heart rate. Subjects in the higher maximum V O 2 group were heavier, had lower ventilatory efficiency, and had a reduced breathing reserve. Multivariate logistic regression analysis showed that the predominant independent factors associated with group assignment were body mass index, breathing reserve, and peak heart rate. The subjects with higher percent-of-predicted peak work than peak V O 2 had a lower body mass index, a greater breathing reserve, and a higher peak heart rate. CONCLUSIONS: The observation that there are distinguishing physiological features between those who have a higher peak work and those who have higher peak V O 2 provides insight into the underlying processes determining maximal exercise capacity.

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Oxygen consumption is increased relative to work rate in patients with McArdle's disease

Cited by 14 publications

References 42 publications

Effects of Gas Exchange on Acid‐Base Balance

Effects of Gas Exchange on Acid‐Base Balance

Myophosphorylase deficiency (McArdle disease) in a patient with normal pregnancy and normal pregnancy outcome

Assessing Maximal Exercise Capacity: Peak Work or Peak Oxygen Consumption?

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