Control of Skin Sympathetic Nerve Activity During Intermittent Static Handgrip Exercise

Leuenberger, Urs A.; Mostoufi‐Moab, Sogol; Herr, Michael D.; Gray, Kristen S.; Kunselman, Allen R.; Sinoway, Lawrence I.

doi:10.1161/01.cir.0000093280.40118.30

Cited by 16 publications

(15 citation statements)

References 19 publications

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“…Blangsted et al (2004) also found no differences in trapezius muscle activity when psychosocial loads were added to computer work. Recent studies have shown a direct influence of muscular contractions on skin sympathetic activity (Leuenberger et al 2003), and that relative muscular effort influences exercise-induced skin sympathetic activity (Ray and Wilson 2004), which might partly explain our findings of increased electrodermal activity during MDT.…”

Section: Muscle Oxygenationsupporting

confidence: 50%

Effects of time pressure and precision demands during computer mouse work on muscle oxygenation and position sense

Heiden¹,

Lyskov

Djupsjöbacka

et al. 2005

Eur J Appl Physiol

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The present study investigated the effects of time pressure and precision demands during computer mouse work on muscle oxygenation and position sense in the upper extremity. Twenty-four healthy subjects (12 males and 12 females) performed a 45-min standardized mouse-operated computer task on two occasions. The task consisted of painting rectangles that were presented on the screen. On one occasion, time pressure and precision demands were imposed (more demanding task, MDT), whereas, on the other occasion, no such restraints were added (less demanding task, LDT). The order of the two task versions was randomized. Tissue oxygen saturation in the trapezius and extensor carpi radialis muscles was recorded throughout, and the position-matching ability of the wrist was measured before and after the tasks. In addition, measurements of autonomic nervous system reactivity and subjective ratings of tenseness and physical fatigue were obtained. Performance was measured in terms of the number of rectangles that were painted during the task. During MDT, oxygen saturation in extensor carpi radialis decreased (P < 0.05) compared to LDT. These data were paralleled by increased electrodermal activity (P < 0.05), skin blood flow (P < 0.05), ratings of tenseness and fatigue (P < 0.01), and increased performance (P < 0.01) during MDT. Females exhibited lower oxygen saturation than males, during rest as well as during the computer tasks (P < 0.01). Wrist repositioning error increased following LDT as compared to MDT (P < 0.05). In conclusion, computer mouse work under time pressure and precision demands caused a decrease in forearm muscle oxygenation, but did not affect wrist position sense accuracy. We attribute our changes in oxygenation more to increased oxygen consumption as a result of enhanced performance, than to vasoconstriction.

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Section: Muscle Oxygenationsupporting

confidence: 50%

Effects of time pressure and precision demands during computer mouse work on muscle oxygenation and position sense

Heiden¹,

Lyskov

Djupsjöbacka

et al. 2005

Eur J Appl Physiol

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“…However, when expressed solely as total activity, this value does not identify whether changes in SSNA activation occurred via increase in amplitude and/or increase in burst frequency. Although quantification of SSNA via burst rate has been used in some studies (9,11,12,16), SSNA burst number can be very difficult to count, because integrated SSNA bursts are irregular and are not synchronized with the cardiac cycle (7), and some bursts have more than one peak (Fig. 1).…”

Section: Perspectivesmentioning

confidence: 99%

Spectral characteristics of skin sympathetic nerve activity in heat-stressed humans

Cui¹,

Sathishkumar²,

Wilson³

et al. 2006

American Journal of Physiology-Heart and Circulatory Physiology

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Skin sympathetic nerve activity (SSNA) exhibits low- and high-frequency spectral components in normothermic subjects. However, spectral characteristics of SSNA in heat-stressed subjects are unknown. Because the main components of the integrated SSNA during heat stress (sudomotor/vasodilator activities) are different from those during normothermia and cooling (vasoconstrictor activity), we hypothesize that spectral characteristics of SSNA in heat-stressed subjects will be different from those in subjects subjected to normothermia or cooling. In 17 healthy subjects, SSNA, electrocardiogram, arterial blood pressure (via Finapres), respiratory activity, and skin blood flow were recorded during normothermia and heat stress. In 7 of the 17 subjects, these variables were also recorded during cooling. Spectral characteristics of integrated SSNA, R-R interval, beat-by-beat mean blood pressure, skin blood flow variability, and respiratory excursions were assessed. Heat stress and cooling significantly increased total SSNA. SSNA spectral power in the low-frequency (0.03-0.15 Hz), high-frequency (0.15-0.45 Hz), and very-high-frequency (0.45-2.5 Hz) regions was significantly elevated by heat stress and cooling. Interestingly, heat stress caused a greater relative increase of SSNA spectral power within the 0.45- to 2.5-Hz region than in the other spectral ranges; cooling did not show this effect. Differences in the SSNA spectral distribution between normothermia/cooling and heat stress may reflect different characteristics of central modulation of vasoconstrictor and sudomotor/vasodilator activities.

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“…This exercise-induced increase in skin sympathetic nerve activity (SSNA) is controlled by the engagement of central command and activation of muscle mechanoreceptors, and it may be controlled, under very specific conditions, by activation of muscle metaboreceptors (11). Unlike muscle sympathetic nerve activity, the precise determinants of exercise-induced increases in SSNA are equivocal.…”

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confidence: 99%

Determinants of skin sympathetic nerve responses to isometric exercise

Wilson

Dyckman²,

Ray³

2006

Journal of Applied Physiology

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Determinants of skin sympathetic nerve responses to isometric exercise. J Appl Physiol 100: 1043-1048, 2006. First published November 10, 2005 doi:10.1152/japplphysiol.00579.2005.-Exercise-induced increases in skin sympathetic nerve activity (SSNA) are similar between isometric handgrip (IHG) and leg extension (IKE) performed at 30% of maximal voluntary contraction (MVC). However, the precise effect of exercise intensity and level of fatigue on this relationship is unclear. This study tested the following hypotheses: 1) exercise intensity and fatigue level would not affect the magnitude of exercise-induced increase in SSNA between IHG and IKE, and 2) altering IHG muscle mass would also not affect the magnitude of exercise-induced increase in SSNA. In protocol 1, SSNA (peroneal microneurography) was measured during baseline and during the initial and last 30 s of isometric exercise to volitional fatigue in 12 subjects who randomly performed IHG and IKE bouts at 15, 30, and 45% MVC. In protocol 2, SSNA was measured in eight subjects who performed one-arm IHG at 30% MVC with the addition of IHG of the contralateral arm in 10-s intervals for 1 min. Exercise intensity significantly increased SSNA responses during the first 30 s of IHG (34 Ϯ 13, 70 Ϯ 11, and 92 Ϯ 13% change from baseline) and IKE (30 Ϯ 17, 69 Ϯ 12, and 76 Ϯ 13% change from baseline) for 15, 30, and 45% MVC. During the last 30 s of exercise to volitional fatigue, there were no significant differences in SSNA between exercise intensities or limb. SSNA did not significantly change between onearm and two-arm IHG. Combined, these data indicate that exerciseinduced increases in SSNA are intensity dependent in the initial portion of isometric exercise, but these differences are eliminated with the development of fatigue. Moreover, the magnitude of exerciseinduced increase in SSNA responses is not dependent on either muscle mass involved or exercising limb. skin blood flow; sweat rate; and microneurography SYMPATHETIC OUTFLOW TO THE skin is increased during isometric and rhythmic exercise (7,12,26). This exercise-induced increase in skin sympathetic nerve activity (SSNA) is controlled by the engagement of central command and activation of muscle mechanoreceptors, and it may be controlled, under very specific conditions, by activation of muscle metaboreceptors (11). Unlike muscle sympathetic nerve activity, the precise determinants of exercise-induced increases in SSNA are equivocal.Previous studies indicate that the exercise-induced increases in SSNA are intensity dependent to ϳ45% of maximal voluntary contraction (MVC) and that level of effort modulates SSNA responses to isometric exercise (27,28). Seals (20) observed another determinant to exercise-induced increases in SSNA by demonstrating that the level of fatigue may be a prime factor regardless of exercise intensity. In these experiments, he observed no difference in SSNA responses between higher exercise intensities (i.e., 45 and 60% MVC) during isometric handgrip (IHG) at and near volitional fatigu...

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Control of Skin Sympathetic Nerve Activity During Intermittent Static Handgrip Exercise

Cited by 16 publications

References 19 publications

Effects of time pressure and precision demands during computer mouse work on muscle oxygenation and position sense

Effects of time pressure and precision demands during computer mouse work on muscle oxygenation and position sense

Spectral characteristics of skin sympathetic nerve activity in heat-stressed humans

Determinants of skin sympathetic nerve responses to isometric exercise

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