Norepinephrine spillover from skeletal muscle during exercise in humans: role of muscle mass

Savard, G.; Richter, Erik A.; Strange, S.; Christensen, Niels Juel; Saltin, Bengt

doi:10.1152/ajpheart.1989.257.6.h1812

Cited by 80 publications

(104 citation statements)

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“…a respiratory 'steal' phenomenon). Also, in contrast to the findings of Secher et al (1977), but consistent with the results of Richardson et al (1995), Richter et al (1992), Savard et al (1989), Strange (1999), and most recently Wetter et al (1999), our data suggest that when exercise intensity, and thus cardiac output and muscle O 2 extraction, is not maximal, blood flow to active muscle is not reduced as a result of increases in active muscle mass that occur during a period of resistive breathing.…”

Section: Discussionsupporting

confidence: 87%

“…The power output and thus ◊J for the heavy-intensity exercise used in the present study was lower than that used by Harms et al (1997;1998), but higher than that used by Secher et al (1977) and others (Savard et al 1989;Richter et al 1992;Richardson et al 1995), and could be tolerated for 12 ± 1 min before fatigue. Consistent with the supra-U L intensity, the associated ◊J response in the present study increased slowly and progressively throughout the exercise period (i.e.…”

Section: _1mentioning

confidence: 50%

“…However, several other studies using similar exercise protocols with exercise intensities ranging between 24 and 82 % ◊J ,max have been unable to confirm these findings (Savard et al 1989;Richter et al 1992;Richardson et al 1995). These differences may reflect the increased noradrenaline spillover in these latter studies, the associated lower leg vascular conductance suggesting that vasoconstriction had constrained further increases in leg blood flow (Savard et al 1989;Richter et al 1992).…”

Section: _1mentioning

confidence: 84%

“…Thus, for the combined arm-leg exercise (◊J= 3.4 l min _1 or 78 % of ◊J ,max ), leg blood flow was reduced by ~15 % (from 12.4 to 10.5 l min _1 ) and the arterio-venous O 2 difference across the exercising leg muscle increased by ~13 % (from 156 to 176 ml l _1 ) to compensate for the reduced flow, with no change in pulmonary or leg ◊J (Secher et al 1977). However, several other studies using similar exercise protocols with exercise intensities ranging between 24 and 82 % ◊J ,max have been unable to confirm these findings (Savard et al 1989;Richter et al 1992;Richardson et al 1995). These differences may reflect the increased noradrenaline spillover in these latter studies, the associated lower leg vascular conductance suggesting that vasoconstriction had constrained further increases in leg blood flow (Savard et al 1989;Richter et al 1992).…”

Section: _1mentioning

confidence: 95%

“…In this study, the reduction in leg blood flow was associated with a compensatory increase in its arterio-venous O 2 content difference with leg ◊J being maintained. Others, using combinations of leg and arm exercise to increase the mass of active muscle, have been unable to confirm that recruitment of additional muscle groups leads to reductions in blood flow to active leg muscle during submaximal exercise (Savard et al 1989;Richter et al 1992;Richardson et al 1995;Strange, 1999). Recently, Wetter et al (1999) demonstrated that when exercising at a submaximal power output requiring 75 % ◊J ,max , leg ◊J and leg muscle blood flow were lower (with no change in arterio-venous O 2 content difference) during a period of inspiratory 'resistive' breathing compared to a period of respiratory 'unloaded' breathing, although no such differences were found relative to normal breathing or when exercising at only 50 % ◊J ,max .…”

mentioning

confidence: 99%

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The Effect of Resistive Breathing on Leg Muscle Oxygenation Using Near‐Infrared Spectroscopy During Exercise in Men

Kowalchuk

Rossiter

Ward

et al. 2002

Experimental Physiology

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The effect of added respiratory work on leg muscle oxygenation during constant‐load cycle ergometry was examined in six healthy adults. Exercise was initiated from a baseline of 20 W and increased to a power output corresponding to 90% of the estimated lactate threshold (moderate exercise) and to a power output yielding a tolerance limit of 11.8 min (± 1.4, S.D.) (heavy exercise). Ventilation and pulmonary gas exchange were measured breath‐by‐breath. Profiles of leg muscle oxygenation were determined throughout the protocol using near‐infrared (NIR) spectroscopy (Hamamatsu NIRO 500) with optodes aligned midway along the vastus lateralis of the dominant leg. Four conditions were tested: (i) control (Con) where the subjects breathed spontaneously throughout, (ii) controlled breathing (Con Br) where breathing frequency and tidal volume were matched to the Con profile, (iii) increased work of breathing (Resist Br) in which a resistance of 7 cmH2O l−1 s−1 was inserted into the mouthpiece assembly, and (iv) partial leg blood flow occlusion (Leg Occl), where muscle perfusion was reduced by inflating a pressure cuff (∼90 mmHg) around the upper right thigh. During Resist Br and Leg Occl, subjects controlled their breathing pattern to reproduce the ventilatory profile of Con. An ∼3 min period with respiratory resistance or pressure cuff was introduced ∼4 min after exercise onset. NIR spectroscopy data for reduced haemoglobin‐myoglobin (Δ[Hb]) were extracted from the continuous display at specific times prior to, during and after removal of the resistance or pressure cuff. While the Δ[Hb] increased during moderate‐ and heavy‐intensity exercise, there was no additional increase in Δ[Hb] with Resist Br. In contrast, Δ[Hb] increased further with Leg Occl, reflecting increased muscle O2 extraction during the period of reduced muscle blood flow. In conclusion, increasing the work of breathing did not increase leg muscle deoxygenation during heavy exercise. Assuming that leg muscle O2 consumption did not decrease, this implies that leg blood flow was not reduced consequent to a redistribution of flow away from the working leg muscle.

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Section: Discussionsupporting

confidence: 87%

Section: _1mentioning

confidence: 50%

Section: _1mentioning

confidence: 84%

Section: _1mentioning

confidence: 95%

mentioning

confidence: 99%

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The Effect of Resistive Breathing on Leg Muscle Oxygenation Using Near‐Infrared Spectroscopy During Exercise in Men

Kowalchuk

Rossiter

Ward

et al. 2002

Experimental Physiology

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Peripheral adaptations to endurance training—Effect of active muscle mass

2019

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This is an open access article under the terms of the Creat ive Commo ns Attri butio n-NonCo mmercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. AbstractThe purpose of this study was to evaluate whether adaptations to endurance training are affected by active muscle mass during training. Eleven healthy subjects performed 5 weeks of one-legged knee extension (1-KE) training with both legs, separately. During the 1-KE workouts for one of the legs, arm cycling was added (1L2A), while the other leg only performed 1-KE (1L). During the training sessions, the 1-KE power output and session duration were equal for both legs. Whole-body oxygen uptake (VȮ 2 ), adrenaline, and noradrenaline plasma concentrations were 112% ± 11%, 139% ± 144%, and 197% ± 101% higher during 1L2A than 1L, respectively. However, this did not affect the 1-KE training adaptations since submaximal O 2 -cost, heart rate and blood lactate concentration, maximal VȮ 2 , and power output all improved equally in both legs. This was supported by similar capillarization and concentration of oxidative enzymes in the legs after the training period. The present study therefore indicates that the size of active muscle mass per se during exercise does not affect adaptations to endurance training. K E Y W O R D S arm cranking, muscle fiber, pulmonary oxygen uptake, single-leg, skeletal muscle, training adaptation ORCID Knut Sindre Mølmen https://orcid. org/0000-0001-8924-6848 How to cite this article: Mølmen KS, Hallén J, Rud B. Peripheral adaptations to endurance training-Effect of active muscle mass. Transl Sports Med.

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The Oxygen Transport System and Maximal Oxygen Uptake

Mitchell¹,

Saltin²

2003

Exercise Physiology

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Norepinephrine spillover from skeletal muscle during exercise in humans: role of muscle mass

Cited by 80 publications

References 0 publications

The Effect of Resistive Breathing on Leg Muscle Oxygenation Using Near‐Infrared Spectroscopy During Exercise in Men

The Effect of Resistive Breathing on Leg Muscle Oxygenation Using Near‐Infrared Spectroscopy During Exercise in Men

Peripheral adaptations to endurance training—Effect of active muscle mass

The Oxygen Transport System and Maximal Oxygen Uptake

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