Effect of muscle mass on muscle mechanoreflex-mediated heart rate increase at the onset of dynamic exercise

Vianna, Lauro C.; Oliveira, Ricardo B.; Ramos, Plínio dos Santos; Ricardo, Djalma Rabelo; Araújo, Cláudio Gil Soares de

doi:10.1007/s00421-009-1237-9

Cited by 20 publications

(18 citation statements)

References 32 publications

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“…It is recognized that the CVW at the onset of exercise is governed by a complex redundant neural interaction between descending impulses originating from higher centers of the brain directed to skeletal muscles, which in parallel influence the activity of autonomic neurons (central command mechanism -feedforward system) (Williamson et al 1995(Williamson et al , 2006, and muscle afferent impulses mostly from type III fibers, which are predominantly mechanically sensitive and provide information to autonomic neurons about the state of peripheral muscles (peripheral mechanism -feedback system) (McCloskey and Mitchell 1972;Vianna et al 2010). The central and peripheral neural mechanisms inhibit the cardiac vagal activity (Lador et al 2006) and reset the arterial baroreflex operating point (DiCarlo and Bishop 1992), thus increasing the HR.…”

Section: Methodological Considerationsmentioning

confidence: 99%

Cardiac vagal withdrawal and reactivation during repeated rest–exercise transitions

et al. 2010

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It is not known whether subjects that have higher cardiac vagal reactivation (CVR) during repeated exercise transitions also have higher cardiac vagal withdrawal (CVW) at the onset of exercise, which would lead to better heart rate (HR) regulation during exercise transitions. Therefore, our aims were to investigate: (a) the influence of CVR on CVW during repeated rest-exercise transitions; and (b) the influence of the sympathetic activity on CVR and CVW. Fifty-eight healthy men (22 ± 4 years) performed 20 rest-exercise transitions interspaced by 30 s. In addition, nine healthy men (24 ± 3 years) ingested either 25 mg of atenolol or placebo, on a crossover, double-blind, randomized design, then performed 20 rest-exercise transitions interspaced by 30 s. Cardiac vagal reactivation was assessed by a HR variability index (RMSSD) and CVW by the HR increase at the onset of a valid and reliable cycling protocol. The CVR and CVW responses were associated (partial r ranged from 0.60 to 0.66; p < 0.05). Participants with higher CVR over transitions maintained their CVW over repeated transitions [first transition (mean ± SEM) = 1.59 ± 0.04 vs. 20th = 1.50 ± 0.03 (a.u.), p = 0.24], while participants with lower CVR had a CVW decrease over repeated transitions [first transition (mean ± SEM) = 1.38 ± 0.04 vs. 20th = 1.19 ± 0.03 (a.u.), p < 0.01). In addition, the CVR and CVW over the rest-exercise transitions were similar during atenolol and placebo (ANCOVA interaction p = 0.12 and p = 0.48, respectively). In conclusion, the CVR among repeated rest-exercise transitions influenced the CVW at the onset of exercise, which was not affected by a partial β(1) cardioselective adrenoceptor blockade.

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Section: Methodological Considerationsmentioning

confidence: 99%

Cardiac vagal withdrawal and reactivation during repeated rest–exercise transitions

et al. 2010

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“…Experimental sessions consisted of three 5-s bouts of passive unloading cycling followed by three 5-s bouts of active unloading cycling separated by at least 5 min with a metronome-controlled cadence of 1 Hz. Each exercise bout was performed at the end-expiratory breath to avoid the possible confounding influence of respiratory sinus arrhythmia (17,24,41,49,60). Passive movement was carried out by the experimenter manually cycling the subject's legs in which visual and auditory feedback from EMG were provided to the subjects throughout passive cycling trials to help him/her keep leg muscles relaxed (38,39,60,63).…”

Section: Subjectsmentioning

confidence: 99%

“…It has been proposed that the isolation of muscle mechanoreflex can be evoked by passive movement (11,25,38,39,60,63) or muscle stretch (9,12,22). Interestingly, Nóbrega and Araújo (38) observed a similar increase in HR during voluntary and passive cycling, indicating that the HR response at the onset of exercise is not affected when central command and muscle metaboreflex are absent.…”

Section: Introductionmentioning

confidence: 99%

GABAergic contribution to the muscle mechanoreflex-mediated heart rate responses at the onset of exercise in humans

Teixeira

Ramos

Samora

et al. 2018

American Journal of Physiology-Heart and Circulatory Physiology

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Previous studies have indicated that central GABAergic mechanisms are involved in the heart rate (HR) responses at the onset of exercise. On the basis of previous research that showed similar increases in HR during passive and active cycling, we reasoned that the GABAergic mechanisms involved in the HR responses at the exercise onset are primarily mediated by muscle mechanoreceptor afferents. Therefore, in this study, we sought to determine whether central GABA mechanisms are involved in the muscle mechanoreflex-mediated HR responses at the onset of exercise in humans. Twenty-eight healthy subjects (14 men and 14 women) aged between 18 and 35 yr randomly performed three bouts of 5-s passive and active cycling under placebo and after oral administration of diazepam (10 mg), a benzodiazepine that produces an enhancement in GABA activity. Beat-to-beat HR (electrocardiography) and arterial blood pressure (finger photopletysmography) were continuously measured. Electromyography of the vastus lateralis was obtained to confirm no electrical activity during passive trials. HR increased from rest under placebo and further increased after administration of diazepam in both passive (change: 12 ± 1 vs. 17 ± 1 beats/min, P < 0.01) and active (change: 14 ± 1 vs. 18 ± 1 beats/min, P < 0.01) cycling. Arterial blood pressure increased from rest similarly during all conditions ( P > 0.05). Importantly, no sex-related differences were found in any variables during experiments. These findings demonstrate, for the first time, that the GABAergic mechanisms significantly contribute to the muscle mechanoreflex-mediated HR responses at the onset of exercise in humans. NEW & NOTEWORTHY We found that passive and voluntary cycling evokes similar increases in heart rate and that these responses were enhanced after diazepam administration, a benzodiazepine that enhances GABA activity. These findings suggest that the GABAergic system may contribute to the muscle mechanoreflex-mediated vagal withdrawal at the onset of exercise in humans.

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“…chemoreflex, hemodynamics, mechanoreflex, metaboreflex, ventilation metaboreflex responds primarily to chemical stimuli, notably metabolite build-up postexercise (e.g., lactic acid) via unmyelinated group IV afferent fibers (Rotto & Kaufman, 1988;Sinoway, Hill, Pickar, & Kaufman, 1993;Thimm & Baum, 1987), while the mechanoreflex responds primarily to mechanical muscle activity via thinly myelinated group III afferent fibers (Hayes & Kaufman, 2001;Mark, Victor, Nerhed, & Wallin, 1985). Overall, the exercise pressor response results in higher sympathetic output, heart rate (HR), cardiac output (Q), and mean arterial pressure (MAP) (Edgell & Stickland, 2014;Jarvis et al, 2011;Katayama et al, 2018;Llwyd, Panerai, & Robinson, 2017;Vianna, Oliveira, Ramos, Ricardo, & Araujo, 2010). The CO 2 chemoreflex is also activated during prolonged high intensity exercise above the anaerobic threshold, stimulating respiratory compensation to metabolic acidosis from increased lactate and CO 2 production (Eldridge, Kiley, & Millhorn, 1985;Rausch, Whipp, Wasserman, & Huszczuk, 1991;Teppema, Barts, & Evers, 1984).…”

Section: Introductionmentioning

confidence: 99%

Oral contraceptives and menstrual cycle influence autonomic reflex function

et al. 2020

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Progesterone and its analogues are known to influence ventilation. Therefore, the purpose of this study was to investigate the role of endogenous and pharmaceutical female sex hormones in ventilatory control during the activation of the metaboreflex, mechanoreflex, and CO2 chemoreflex. Women aged 18–30 taking (n = 14) or not taking (n = 12) oral contraceptives (OC and NOC, respectively) were tested in the low hormone (LH) and high hormone (HH) conditions corresponding to the early follicular and mid‐luteal phases (NOC) or placebo and high‐dose pills (OC). Women underwent three randomized trials: (a) 3 min of passive leg movement (PLM), (b) 2 min of 40% maximal voluntary handgrip exercise followed by 2 min of post‐exercise circulatory occlusion (PECO), and (c) 5 min of breathing 5% CO2. We primarily measured hemodynamics and ventilation. During PLM, the OC group had a smaller pressor response (p = .012). During PECO, the OC group similarly exhibited a smaller pressor response (p = .043) and also exhibited a greater ventilatory response (p = .024). Lastly, in response to breathing 5% CO2, women in the HH phase had a greater ventilatory response (p = .022). We found that OC use attenuates the pressor response to both the metaboreflex and mechanoreflex while increasing the ventilatory response to metaboreflex activation. We also found evidence of an enhanced CO2 chemoreflex in the HH phase. We hypothesize that OC effects are from the chronic upregulation of pulmonary and vascular β‐adrenergic receptors. We further suggest that the increased cyclic progesterone in the HH phase enhances the chemoreflex.

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Effect of muscle mass on muscle mechanoreflex-mediated heart rate increase at the onset of dynamic exercise

Cited by 20 publications

References 32 publications

Cardiac vagal withdrawal and reactivation during repeated rest–exercise transitions

Cardiac vagal withdrawal and reactivation during repeated rest–exercise transitions

GABAergic contribution to the muscle mechanoreflex-mediated heart rate responses at the onset of exercise in humans

Oral contraceptives and menstrual cycle influence autonomic reflex function

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