III. Arbeitsfähigkeit und Ernährung<sup>1</sup>

Christensen, E. Hohwü; Hansen, Ove

doi:10.1111/j.1748-1716.1939.tb01320.x

Cited by 246 publications

(113 citation statements)

References 2 publications

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“…It is known that propranolol inhibits either lipolysis or glycolysis (Lundborg et al, 1981;Deacon, 1978;Issekutz, 1978), but it is also likely that the utilization of free fatty acids as a fuel is more compromised than that of glucose (Lundborg et al, 1981). Under these circumstances V0, must be reduced, since the caloric value of 1 1 Of 02 iS greater for carbohydrates than fat metabolism, whereas tissue respiratory quotient (RQ) increases (Christensen & Hansen, 1939;Douglas & Priestly, 1948).…”

Section: Discussionmentioning

confidence: 99%

Effects of beta‐adrenoceptor blockade on exercise performance and respiratory response in healthy, physically untrained humans.

Violante¹,

Buccheri²,

Brusasco³

1984

Brit J Clinical Pharma

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The effects of propranolol 80 mg orally were compared with those of placebo on the response to a stepwise increasing exercise test in 17 healthy and physically untrained volunteers, of whom eight were female. Propranolol showed no significant effects on maximum work rate or perceived exertion rate. However, submaximal O2 uptake, CO2 output and minute ventilation tended to be lower after propranolol than after placebo. It is concluded that in subjects with a low work capacity, beta‐adrenoceptor blockade does not impair maximal exercise capacity. The mechanisms underlying changes in respiratory response to exercise after propranolol are not fully explained. However, changes in substrate utilisation, the reduction in cardiac output and an alteration in respiratory drive may all be involved.

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Section: Discussionmentioning

confidence: 99%

Effects of beta‐adrenoceptor blockade on exercise performance and respiratory response in healthy, physically untrained humans.

Violante¹,

Buccheri²,

Brusasco³

1984

Brit J Clinical Pharma

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“…It is also known that dietary status is of importance for metabolism and performance during exercise. Thus, ingestion of a fat-rich diet for 3-5 days decreases carbohydrate metabolism and performance during exercise in man (Christensen & Hansen, 1939;Bergstrom, Hermansen, Hultman & Saltin, 1967;Galbo, Holst & Christensen, 1979). However, studies in man (Phinney, Bistrian, Evans, Gervino & Blackburn, 1983;Muoio, Leddy, Horvath, Awad & Pendergast, 1994;Lambert, Speechly, Dennis & Noakes, 1994) and rat (Miller, Bryce & Conlee, 1984;Conlee, Hammer, Winder, Bracken, Nelson & Barnett, 1990;Simi, Sempore, Mayet & Favier, 1991) have also suggested that when a fat-rich diet is ingested for 1-5 weeks, endurance may not be impaired (Phinney et al 1983;Conlee et al 1990) and may even be improved (Miller et al 1984;Simi et al 1991;Muoio et al 1994;Lambert et al 1994).…”

mentioning

confidence: 98%

Interaction of training and diet on metabolism and endurance during exercise in man.

Helge

Richter

1996

The Journal of Physiology

144

130

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1. Ten untrained young men ingested a carbohydrate-rich diet (65 energy percent (E %) carbohydrate, T-CHO) and ten similar subjects a fat-rich diet (62 E% fat, T-FAT) while endurance training was performed 3-4 times a week for 7 weeks. For another 8th week of training both groups ingested the carbohydrate-rich diet (T-CHO and T-FAT/CHO). 2. Maximal oxygen uptake increased by 11 % (P < 0 05) in both groups after 7 and 8 weeks.Time to exhaustion at 81 % of pre-training maximal oxygen uptake increased significantly from a mean (± S.E.M.) of 35 + 4 min to 102 + 5 and 65 + 7 min in T-CHO and T-FAT, respectively, after 7 weeks (P < 0 05, T-CHO vs. T-FAT). After 8 weeks, endurance remained unchanged in T-CHO but increased (P < 0 05) to 77 + 9 min in T-FAT/CHO which, however, was still less (P < 0 05) than in T-CHO. 3. Muscle glycogen breakdown rate during exercise was halved by endurance training equally in both T-CHO and T-FAT after 7 and 8 weeks, and muscle glycogen stores at exhaustion were not depleted in any group. 4. During exercise after 7 weeks, the respiratory exchange ratio (RER) was unchanged in T-CHO (0-88 + 0 01) compared with pre-training but decreased (P < 0 05) to 0-82 + 0-02 in T-FAT. After 8 weeks, RER in both T-CHO and T-FAT/CHO was approximately 0-87. 5. During exercise, plasma noradrenaline concentration and heart rate were higher in T-FAT than in T-CHO both at 7 and at 8 weeks. 6. It is concluded that ingesting a fat-rich diet during an endurance training programme is detrimental to improvement in endurance. This is not due to a simple lack of carbohydrate fuel, but rather to suboptimal adaptations that are not remedied by short-term increased carbohydrate availability. Furthermore, the study suggests that the decrease in RER usually seen after training when exercising at the same absolute intensity as before training can be prevented by a carbohydrate-rich diet.Physical endurance training results in marked changes in muscle metabolism and endurance during exercise. Classical adaptations to training include a switch to increased fat metabolism when exercising on the same absolute intensity as before training (

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“…The lower rate of ATP turnover can be matched by oxidative phosphorylation that employs a combination of glucose/glycogen and fatty acids as the substrates. Early studies demonstrated the balance between fat and carbohydrate oxidation through indirect calorimetry method using expired gases (Christensen & Hansen 1939, Asmussen 1971. The use of the needle biopsy technique by Bergstrom & Hultman (1966) permitted direct measurement of intramuscular substrates, primarily glycogen and the glycolytic intermediates.…”

Section: Muscle Energetics and The Metabolic Demands Of Exercisementioning

confidence: 99%

Metabolic and endocrine response to exercise: sympathoadrenal integration with skeletal muscle

Ball¹

2014

Journal of Endocrinology

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Skeletal muscle has the capacity to increase energy turnover by w1000 times its resting rate when contracting at the maximum force/power output. Since ATP is not stored in any appreciable quantity, the muscle requires a coordinated metabolic response to maintain an adequate supply of ATP to sustain contractile activity. The integration of intracellular metabolic pathways is dependent upon the cross-bridge cycling rate of myosin and actin, substrate availability and the accumulation of metabolic byproducts, all of which can influence the maintenance of contractile activity or result in the onset of fatigue. In addition, the mobilisation of extracellular substrates is dependent upon the integration of both the autonomic nervous system and endocrine systems to coordinate an increase in both carbohydrate and fat availability. The current review examines the evidence for skeletal muscle to generate power over short and long durations and discusses the metabolic response to sustain these processes. The review also considers the endocrine response from the perspective of the sympathoadrenal system to integrate extracellular substrate availability with the increased energy demands made by contracting skeletal muscle. Finally, the review briefly discusses the evidence that muscle acts in an endocrine manner during exercise and what role this might play in mobilising extracellular substrates to augment the effects of the sympathoadrenal system.

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III. Arbeitsfähigkeit und Ernährung¹

Cited by 246 publications

References 2 publications

Effects of beta‐adrenoceptor blockade on exercise performance and respiratory response in healthy, physically untrained humans.

Effects of beta‐adrenoceptor blockade on exercise performance and respiratory response in healthy, physically untrained humans.

Interaction of training and diet on metabolism and endurance during exercise in man.

Metabolic and endocrine response to exercise: sympathoadrenal integration with skeletal muscle

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III. Arbeitsfähigkeit und Ernährung1

Cited by 246 publications

References 2 publications

Effects of beta‐adrenoceptor blockade on exercise performance and respiratory response in healthy, physically untrained humans.

Effects of beta‐adrenoceptor blockade on exercise performance and respiratory response in healthy, physically untrained humans.

Interaction of training and diet on metabolism and endurance during exercise in man.

Metabolic and endocrine response to exercise: sympathoadrenal integration with skeletal muscle

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III. Arbeitsfähigkeit und Ernährung¹