Effects of systemic arterial blood pressure  on the contractile force of a human hand muscle

Wright, Julie R.; McCloskey, D.I.; Fitzpatrick, Richard C.

doi:10.1152/jappl.2000.88.4.1390

Cited by 24 publications

(34 citation statements)

References 17 publications

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“…Conversely, minimal flow recovery was observed when local forearm perfusion pressure was acutely reduced via positional changes (i.e., forearm above heart level) (498). A lack of flow restoration with positional perfusion lowering is further supported by the idea that muscle force production is reduced and fatigue can be increased by reductions in perfusion pressure (517,518). Taken together, the magnitude of flow restoration or compensation and mechanisms involved appear to be dependent on the experimental approach used to induce hypoperfusion in contracting skeletal muscle.…”

Section: O Blood-borne Vasodilator Substancesmentioning

confidence: 98%

Regulation of Increased Blood Flow (Hyperemia) to Muscles During Exercise: A Hierarchy of Competing Physiological Needs

Joyner

Casey

2015

Physiological Reviews

552

513

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LJoyner MJ, Casey DP. Regulation of Increased Blood Flow (Hyperemia) to Muscles During Exercise: A Hierarchy of Competing Physiological Needs. Physiol Rev 95: 549 -601, 2015; doi:10.1152/physrev.00035.2013.-This review focuses on how blood flow to contracting skeletal muscles is regulated during exercise in humans. The idea is that blood flow to the contracting muscles links oxygen in the atmosphere with the contracting muscles where it is consumed. In this context, we take a top down approach and review the basics of oxygen consumption at rest and during exercise in humans, how these values change with training, and the systemic hemodynamic adaptations that support them. We highlight the very high muscle blood flow responses to exercise discovered in the 1980s. We also discuss the vasodilating factors in the contracting muscles responsible for these very high flows. Finally, the competition between demand for blood flow by contracting muscles and maximum systemic cardiac output is discussed as a potential challenge to blood pressure regulation during heavy large muscle mass or whole body exercise in humans. At this time, no one dominant dilator mechanism accounts for exercise hyperemia. Additionally, complex interactions between the sympathetic nervous system and the microcirculation facilitate high levels of systemic oxygen extraction and permit just enough sympathetic control of blood flow to contracting muscles to regulate blood pressure during large muscle mass exercise in humans.

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Section: O Blood-borne Vasodilator Substancesmentioning

confidence: 98%

Regulation of Increased Blood Flow (Hyperemia) to Muscles During Exercise: A Hierarchy of Competing Physiological Needs

Joyner

Casey

2015

Physiological Reviews

552

513

View full text Add to dashboard Cite

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“…The different rate of increase in mean arterial pressure when the upper arm was vertical suggests that the muscle mass involved differed for the two tasks (66,69). Indeed, the EMG activity for the anterior deltoid muscle increased more rapidly during the position task when the upper arm was vertical (33), whereas the rate of increase was similar for the two tasks when the upper arm was horizontal (62).…”

Section: Limb Posturementioning

confidence: 99%

Task failure during fatiguing contractions performed by humans

Maluf¹,

Enoka²

2005

Journal of Applied Physiology

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By comparing the physiological adjustments that occur when two similar fatiguing contractions are performed to failure, it is possible to identify mechanisms that limit the duration of the more difficult task. This approach has been used to study two fatiguing contractions, referred to as the force and position tasks, which differed in the type of feedback given to the subject and the amount of support provided by the surroundings. Even though the two tasks required a similar net muscle torque during submaximal isometric contractions, the duration that the position task could be sustained was consistently much briefer than that for the force task. The position task involved a greater rate of increase in EMG activity and more marked changes in motor unit recruitment and rate coding compared with the force task. These observations are consistent with the hypothesis that the motor unit pool was recruited more rapidly during the position task. The difference in motor unit behavior appeared to be caused by variation in synaptic input, likely involving heightened sensitivity of the stretch reflex during the position task. Upon repeat performances of the two fatiguing contractions, some subjects were able to increase the time to failure for the force task but not the position task. Furthermore, the time to failure for the position task could be influenced by the postural demands associated with maintaining the position of the limb, and the difference in the two durations was enhanced when the postural activity evoked a pressor response. These observations indicate that the difference in the duration of the two fatiguing contractions was attributable to differences in the control strategy used to sustain the tasks and the magnitude of the associated postural activity.

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mentioning

confidence: 99%

“…In contrast, the response of vasoregulatory mechanisms to altered perfusion pressure-induced changes in oxygen delivery may be less effective (31,36,37). Wright et al have demonstrated that force output of electrically stimulated contracting human hand muscle is sensitive to changes in perfusion pressure evoked either by altering hand position relative to heart level (36) or via metaboreflex-induced elevation in systemic arterial blood pressure (37). Similar alterations in electrically stimulated canine muscle force output when oxygen delivery is systematically altered (9) would suggest that in the experiments of Wright et al, exercising muscle blood flow was altered with perfusion pressure and vasoregulatory mechanisms did not fully compensate.…”

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confidence: 99%

Do vasoregulatory mechanisms in exercising human muscle compensate for changes in arterial perfusion pressure?

Walker

Saunders²,

Jensen³

et al. 2007

American Journal of Physiology-Heart and Circulatory Physiology

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We tested the hypothesis that vasoregulatory mechanisms completely counteract the effects of sudden changes in arterial perfusion pressure on exercising muscle blood flow. Twelve healthy young subjects (7 female, 5 male) lay supine and performed rhythmic isometric handgrip contractions (2 s contraction/ 2 s relaxation 30% maximal voluntary contraction). Forearm blood flow (FBF; echo and Doppler ultrasound), mean arterial blood pressure (arterial tonometry), and heart rate (ECG) were measured. Moving the arm between above the heart (AH) and below the heart (BH) level during contraction in steady-state exercise achieved sudden ∼30 mmHg changes in forearm arterial perfusion pressure (FAPP). We analyzed cardiac cycles during relaxation (FBFrelax). In an AH-to-BH transition, FBFrelax increased immediately, in excess of the increase in FAPP (∼69% vs. ∼41%). This was accounted for by pressure-related distension of forearm resistance vasculature [forearm vascular conductance (FVCrelax) increased by ∼19%]. FVCrelax was restored by the second relaxation. Continued slow decreases in FVCrelax stabilized by 2 min without restoring FBFrelax. In a BH-to-AH transition, FBFrelax decreased immediately, in excess of the decrease in FAPP (∼37% vs. ∼29%). FVCrelax decreased by ∼14%, suggesting pressure-related passive recoil of resistance vessels. The pattern of FVCrelax was similar to that in the AH-to-BH transition, and FBFrelax was not restored. These data support rapid myogenic regulation of vascular conductance in exercising human muscle but incomplete flow restoration via slower-acting mechanisms. Local arterial perfusion pressure is an important determinant of steady-state blood flow in the exercising human forearm.

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Effects of systemic arterial blood pressure on the contractile force of a human hand muscle

Cited by 24 publications

References 17 publications

Regulation of Increased Blood Flow (Hyperemia) to Muscles During Exercise: A Hierarchy of Competing Physiological Needs

Regulation of Increased Blood Flow (Hyperemia) to Muscles During Exercise: A Hierarchy of Competing Physiological Needs

Task failure during fatiguing contractions performed by humans

Do vasoregulatory mechanisms in exercising human muscle compensate for changes in arterial perfusion pressure?

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