Impaired oxidative metabolism increases adenine nucleotide breakdown in McArdle's disease

1990 ◽  
Vol 69 (4) ◽  
pp. 1231-1235 ◽  
Author(s):  
K. Sahlin ◽  
N. H. Areskog ◽  
R. G. Haller ◽  
K. G. Henriksson ◽  
L. Jorfeldt ◽  
...  
Keyword(s):  
Heart Rate ◽  
Healthy Subjects ◽  
Adenine Nucleotide ◽  
Tricarboxylic Acid Cycle ◽  
Work Load ◽  
Maximal Heart Rate ◽  
Mcardle's Disease ◽  
Mcardle’S Disease ◽  
Arterial Plasma ◽  
Lactate Levels

Two patients with muscle phosphorylase deficiency [McArdle's disease (McA)] were studied during bicycle exercise at 40 (n = 2) and 60 W (n = 1). Peak heart rate was 170 and 162 beats/min, corresponding to approximately 90% of estimated maximal heart rate. Muscle samples were taken at rest and immediately after exercise from the quadriceps femoris. Lactate content remained low in both muscle and blood. Acetylcarnitine, which constitutes a readily available form of acetyl units and thus a substrate for the tricarboxylic acid cycle, was very low in McA patients both at rest and during exercise, corresponding to approximately 17 and 11%, respectively, of that in healthy subjects. Muscle NADH was unchanged during exercise in McA patients in contrast to healthy subjects, in whom NADH increases markedly at high exercise intensities. Despite low lactate levels, arterial plasma NH3 and muscle inosine 5'-monophosphate increased more steeply relative to work load in McA patients than in healthy subjects. The low postexercise levels of lactate, acetylcarnitine, and NADH in McA patients support the idea that exercise performance is limited by the availability of oxidative fuels. Increases in muscle inosine 5'-monophosphate and plasma NH3 indicate that lack of glycogen as an oxidative fuel is associated with adenine nucleotide breakdown and increased deamination of AMP. It is suggested that the early onset of fatigue in McA patients is caused by an insufficient rate of ADP phosphorylation, resulting in transient increases in ADP.

Tricarboxylic Acid Cycle Intermediates during Incremental Exercise in Healthy Subjects and in Patients with McArdle's Disease

1995 ◽  
Vol 88 (6) ◽  
pp. 687-693 ◽  
Author(s):  
K. Sahlin ◽  
L. Jorfeldt ◽  
K.-G. Henriksson ◽  
S. F. Lewis ◽  
R. G. Haller
Keyword(s):  
Healthy Subjects ◽  
Tricarboxylic Acid Cycle ◽  
Peak Level ◽  
Dry Weight ◽  
Tricarboxylic Acid ◽  
Acid Cycle ◽  
Mcardle's Disease ◽  
Mcardle’S Disease ◽  
Tricarboxylic Acid Cycle Intermediates ◽  
High Work

1. The importance of the level of tricarboxylic acid cycle intermediates (malate, citrate and fumarate) for energy transduction during exercise has been investigated in six healthy subjects and in two patients with muscle phosphorylase deficiency (McArdle's disease). 2. Healthy subjects cycled for 10 min at low (50 W), moderate [130 ± 6 W (mean ± SEM)] and high (226 ± 12 W) work rates, corresponding to 26, 50 and 80% of their maximal O2 uptake, respectively. Patients with McArdle's disease cycled for 11–13 min at submaximal (40 W) rates, and to fatigue at maximal work rates of 60–90 W. 3. In healthy subjects, phosphocreatine was unchanged during low work rates, but decreased to 79 and 32% of the initial level during moderate and high work rates. In patients with McArdle's disease, phosphocreatine decreased to 82 and 34% of the initial level during submaximal and peak exercise. Muscle lactate increased in healthy subjects during exercise at moderate and high work rates, but remained low in patients with McArdle's disease. 4. In healthy subjects, tricarboxylic acid cycle intermediates were similar at rest and at low work rates (0.48 ± 0.04 mmol/kg dry weight), but increased to 1.6 ± 0.2 mmol/kg dry weight and 4.0 ± 0.3 mmol/kg dry weight at moderate and high work rates. The tricarboxylic acid cycle intermediate level in patients with McArdle's disease was similar to that in healthy subjects at rest, but was markedly reduced during exercise when compared at the same relative intensity. The peak level of tricarboxylic acid cycle intermediates in patients with McArdle's disease was 22% of that in healthy subjects. However, when compared at the same absolute workload, tricarboxylic acid cycle intermediates were similar in patients with McArdle's disease and in healthy subjects. 5. The decrease in glutamate and increase in alanine suggest that the alanine aminotransaminase reaction was the major anaplerotic process in healthy subjects. However, in patients with McArdle's disease (n = 1), muscle alanine remained unchanged and the purine nucleotide cycle may instead be the route of a limited anaplerosis during maximal exercise. The muscle content of glutamate and glutamine (n = 1) was markedly reduced in patients with McArdle's disease. 6. It is concluded that the tricarboxylic acid cycle intermediate level is related to the work rate in healthy subjects, and that the attenuated peak level in patients with McArdle's disease may be a limitation for aerobic energy transduction.

Cardiovascular response to cycle exercise during and after pregnancy

1989 ◽  
Vol 66 (1) ◽  
pp. 336-341 ◽  
Author(s):  
S. P. Sady ◽  
M. W. Carpenter ◽  
P. D. Thompson ◽  
M. A. Sady ◽  
B. Haydon ◽  
...  
Keyword(s):  
Heart Rate ◽  
Maximal Exercise ◽  
Cardiovascular Response ◽  
Work Load ◽  
Cycle Ergometry ◽  
Maximal Heart Rate ◽  
O2 Uptake ◽  
Cycle Exercise ◽  
Vascular Beds ◽  
Response To Exercise

Our purpose was to determine if pregnancy alters the cardiovascular response to exercise. Thirty-nine women [29 +/- 4 (SD) yr], performed submaximal and maximal exercise cycle ergometry during pregnancy (antepartum, AP, 26 +/- 3 wk of gestation) and postpartum (PP, 8 +/- 2 wk). Neither maximal O2 uptake (VO2max) nor maximal heart rate (HR) was different AP and PP (VO2 = 1.91 +/- 0.32 and 1.83 +/- 0.31 l/min; HR = 182 +/- 8 and 184 +/- 7 beats/min, P greater than 0.05 for both). Cardiac output (Q, acetylene rebreathing technique) averaged 2.2 to 2.8 l/min higher AP (P less than 0.01) at rest and at each exercise work load. Increases in both HR and stroke volume (SV) contributed to the elevated Q at the lower exercise work loads, whereas an increased SV was primarily responsible for the higher Q at higher levels. The slope of the Q vs. VO2 relationship was not different AP and PP (6.15 +/- 1.32 and 6.18 +/- 1.34 l/min Q/l/min VO2, P greater than 0.05). In contrast, the arteriovenous O2 difference (a-vO2 difference) was lower at each exercise work load AP, suggesting that the higher Q AP was distributed to nonexercising vascular beds. We conclude that Q is greater and a-vO2 difference is less at all levels of exercise in pregnant subjects than in the same women postpartum but that the coupling of the increase in Q to the increase in systemic O2 demand (VO2) is not different.(ABSTRACT TRUNCATED AT 250 WORDS)

Fibrinolytic and hemostatic changes during and after maximal exercise in males

1976 ◽  
Vol 40 (3) ◽  
pp. 287-292 ◽  
Author(s):  
G. L. Davis ◽  
C. F. Abildgaard ◽  
E. M. Bernauer ◽  
M. Britton
Keyword(s):  
Heart Rate ◽  
Factor Viii ◽  
Fibrinolytic Activity ◽  
Work Load ◽  
Bicycle Ergometer ◽  
Maximal Heart Rate ◽  
Relative Level ◽  
Maximum Exercise ◽  
Activity Factor ◽  
Male Subjects

To evaluate changes in fibrinolytic activity, factor VIII and other hematological variables during and after a progressive step increment in work load, 10 healthy male subjects (22–27 yr of age) were exercised to exhaustion on an electromagnetic bicycle ergometer. Blood samples were drawn serially throughout the experiment. Little change in fibrinolytic activity was observed before 70–80% maximum heart rate (MHR) was achieved. Major changes occurred after 80% MHR. Peak values coincided with maximum exercise. In contrast major changes in factor VIII were observed between 95 and 100% MHR with peak values occurring 5–10 min postexercise. An increase in white blood cell count, platelet count, and retention was observed at maximum exercise. One individual failed to demonstrate an increase in either fibrinolytic or factor VIII activity. Relating the data to either the percent maximal oxygen uptake or percent maximal heart rate demonstrates the importance of the exercise protocol and exerting all subjects to the same relative level of physiological work.

Physical work capacity of college women

1965 ◽  
Vol 20 (2) ◽  
pp. 263-266 ◽  
Author(s):  
Ernest D. Michael ◽  
Steven M. Horvath
Keyword(s):  
Heart Rate ◽  
Body Weight ◽  
Exercise Tolerance ◽  
Maximal Exercise ◽  
Work Load ◽  
Work Capacity ◽  
Physical Work ◽  
Physical Work Capacity ◽  
Maximal Heart Rate ◽  
Cardiorespiratory Function

Maximal exercise tolerance tests were given to 30 female subjects 17-22 years old. The test consisted of exercising 1 min at a work load of 300 kpm/min and increasing the work load 150 kpm/min each minute until the subject could no longer exercise. The maximal heart rate level averaged 184 beat/min with a range between 170 and 202 beat/min. The average maximal Vo2 was 1.78 liter/min or 29.8 ml/kg per min. The submaximal ventilatory measurements were similar for all subjects while the heart rate levels at the submaximal work loads differentiated the subjects when grouped according to maximal work-load capacities. Prediction of maximal work capacity could not be made for individuals from any single submaximal measurement. There was .56 correlation between body weight and maximal work capacity with only a .32 relationship between maximal Vo2 and Vo2 per kilogram body weight. exercise tolerance of women; cardiorespiratory function of women during exercise; submaximal cardiorespiratory response; maximal cardiorespiratory measurements of women; response to maximal exercise; prediction of exercise tolerance Submitted on May 5, 1964

Relationship between ammonia, heart rate, and exertion in McArdle's disease

1992 ◽  
Vol 262 (2) ◽  
pp. E167-E172 ◽  
Author(s):  
J. H. Coakley ◽  
A. J. Wagenmakers ◽  
R. H. Edwards
Keyword(s):  
Heart Rate ◽  
Perceived Exertion ◽  
Total Work ◽  
Variable Effect ◽  
Plasma Ammonia ◽  
Mcardle's Disease ◽  
Mcardle’S Disease ◽  
Branched Chain ◽  
Deficiency Type ◽  
Type V

We studied plasma ammonia and exercise tolerance in six patients with McArdle's disease (myophosphorylase deficiency, type V glycogenosis) during incremental cycle ergometry. Tests were performed either in the postabsorptive state or after supplementation with branched-chain amino and 2-oxoacids and glucose. Glucose and branched-chain 2-oxoacid combined increased total work performed from control 49 +/- 22 to 80 +/- 36 kJ (P less than 0.05). Glucose alone also improved total work performed from 49 +/- 22 to 64 +/- 33 kJ (P less than 0.05). Branched-chain 2-oxoacids alone had a variable effect, and branched-chain amino acids were of no benefit. Correlations between plasma ammonia and heart rate for individual patients were r = 0.99, P less than 0.01; r = 0.95, P less than 0.01; r = 0.84, P less than 0.01; r = 0.76, P less than 0.01; r = 0.73, P less than 0.01; and r = 0.63, P less than 0.05 and between ammonia and perceived exertion for all patients combined was r = 0.70, P less than 0.0001. In two patients, correlation of ammonia with heart rate at a power output of 60 W was r = 0.91, P less than 0.001 and at 40 W was r = 0.77, P less than 0.001. We conclude that ammonia is either a mediator or a marker of the metabolic events leading to fatigue.

Maximal heart rate during work in older men

1959 ◽  
Vol 14 (4) ◽  
pp. 562-566 ◽  
Author(s):  
Irma Åstrand ◽  
Per-Olof Åstrand ◽  
Kaare Rodahl
Keyword(s):  
Heart Rate ◽  
Ambient Air ◽  
Work Load ◽  
Work Capacity ◽  
Bicycle Ergometer ◽  
Maximal Heart Rate ◽  
Average Maximum ◽  
Work Up ◽  
Aerobic Work Capacity ◽  
Male Subjects

Nine 56–68-year-old male subjects performed muscular work up to maximal loads on a bicycle ergometer while breathing both ambient air and oxygen. Heart rate increased to an average maximum of 163/min. The maximal O2 intake averaged 2.24 l/min. and the blood lactic acid concentration 85 mg/100 ml. In no case was the maximal heart rate higher when breathing O2 than when breathing air. This low maximal heart rate in older people probably limits the capacity for O2 intake. Four subjects were able to work for about 1 hour without any sign of exhaustion on a work load requiring an O2 consumption of about 50% of their maximal aerobic work capacity. Submitted on October 3, 1958

scholarly journals Myophosphorylase Deficiency (McArdle's Disease): Report of a Family

1976 ◽  
Vol 3 (3) ◽  
pp. 175-179 ◽  
Author(s):  
M. Zafar Mahmud ◽  
R. Rodney Howell ◽  
Roger E. Stevenson ◽  
John Gilroy
Keyword(s):  
Clinical Features ◽  
Quantitative Estimation ◽  
Enzyme Systems ◽  
Mcardle's Disease ◽  
The Family ◽  
Mcardle’S Disease ◽  
Lactate Levels ◽  
Biochemical Abnormalities

SUMMARY:The clinical and biochemical findings are presented of two brothers suffering from McArdle's Disease (Myophosphorylase Deficiency). Tissue enzyme estimations and lactate levels were done in affected and non-affected members of the family. Affected members showed absence of phosphorylase enzyme by histochemical and quantitative estimation. No quantitative abnormalities were found in other enzyme systems of glycolytic pathways in the family investigated. Various other aspects of clinical features, biochemical abnormalities and inheritance are discussed.

Breakdown of adenine nucleotide pool in fatiguing skeletal muscle in McArdle's disease: A noninvasive31P-MRS and EMG study

2003 ◽  
Vol 27 (6) ◽  
pp. 728-736 ◽  
Author(s):  
Jochen Zange ◽  
Torsten Grehl ◽  
Catherine Disselhorst-Klug ◽  
Günter Rau ◽  
Klaus Müller ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Adenine Nucleotide ◽  
Mcardle's Disease ◽  
Mcardle’S Disease ◽  
Adenine Nucleotide Pool

Exercise hyperventilation in patients with McArdle's disease

1982 ◽  
Vol 52 (4) ◽  
pp. 991-994 ◽  
Author(s):  
J. M. Hagberg ◽  
E. F. Coyle ◽  
J. E. Carroll ◽  
J. M. Miller ◽  
W. H. Martin ◽  
...  
Keyword(s):  
Blood Lactate ◽  
Normal Subjects ◽  
O2 Consumption ◽  
Intense Exercise ◽  
Mcardle's Disease ◽  
Normal Individuals ◽  
Mcardle’S Disease ◽  
Muscle Phosphorylase ◽  
Lactate Levels ◽  
End Tidal

This study was undertaken to determine if patients who lack muscle phosphorylase (i.e., McArdle's disease), and therefore the ability to produce lactic acid during exercise, demonstrate a normal hyperventilatory response during progressive incremental exercise. As expected these patients did not increase their blood lactate above resting levels, whereas the blood lactate levels of normal subjects increased 8- to 10-fold during maximal exercise. The venous pH of the normal subjects decreased markedly during exercise that resulted in hyperventilation. The patients demonstrated a distinct increase in ventilation with respect to O2 consumption similar to that seen in normal individuals during submaximal exercise. However their hyperventilation resulted in an increase in pH because there was no underlying metabolic acidosis. End-tidal partial pressures of O2 and CO2 also reflected a distinct hyperventilation in both groups at approximately 70–85% maximal O2 consumption. These data show that hyperventilation occurs during intense exercise, even when there is no increase in plasma [H+]. Since arterial CO2 levels were decreasing and O2 levels were increasing during the hyperventilation, it is possible that nonhumoral stimuli originating in the active muscles or in the brain elicit the hyperventilation observed during intense exercise.

Age-Predicted Maximal Heart Rate in 3320 Healthy Subjects; The HUNT Fitness Study

2011 ◽  
Vol 43 (Suppl 1) ◽  
pp. 628-629
Author(s):  
Bjarne M. Nes ◽  
Ulrik Wisløff ◽  
Asbjørn Støylen ◽  
Trine Karlsen
Keyword(s):  
Heart Rate ◽  
Healthy Subjects ◽  
Maximal Heart Rate
Sign in / Sign up

Export Citation Format

Share Document