Individual Differences in Cardiac and Vascular Components of the Pressor Responses to Isometric Handgrip Exercise in Humans

The purpose of this study was to determine the respective contributions of tachycardia and increases in sympathetic nerve activity (SNA) in mediating the pressor responses to fatiguing vs. nonfatiguing levels of isometric handgrip exercise (IHE) in humans. We performed direct (microneurographic) measurements of muscle SNA from the right peroneal nerve in the leg and recorded arterial pressure (AP) and heart rate (HR) in eight healthy subjects before (control), during, and after 2.5 min of IHE at 15, 25, or 35% of maximal voluntary contraction (MVC). At 15% MVC, AP increased during the initial 1.5 min of IHE (7 mmHg, P less than 0.05) and remained at this level; at 25 and 35% MVC, AP increased throughout IHE (22 and 34 mmHg vs. control, respectively, P less than 0.05). HR increased during the initial 1.5 min of IHE at all three levels (5, 12, and 19 beats/min, respectively, P less than 0.05) but did not increase further over the last minute. At 15% MVC, muscle SNA did not increase above control; during 25 and 35% MVC, muscle SNA did not increase during the 1st min of IHE but increased progressively thereafter (109 and 205% vs. control, respectively, P less than 0.05). The magnitudes of the average increases in AP and muscle SNA over the last minute of IHE were directly related (r = 0.99, P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

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Individual differences in cardiac and vascular components of the pressor response to isometric handgrip exercise in humans

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00699.2013 ◽

2014 ◽

Vol 306 (2) ◽

pp. H251-H260 ◽

Cited By ~ 14

Author(s):

Kazuhito Watanabe ◽

Masashi Ichinose ◽

Rei Tahara ◽

Takeshi Nishiyasu

Keyword(s):

Individual Differences ◽

Arterial Pressure ◽

Pressor Response ◽

Voluntary Contraction ◽

Handgrip Exercise ◽

Isometric Handgrip ◽

Muscle Metaboreflex ◽

Coefficients Of Variation ◽

Isometric Handgrip Exercise ◽

Induced Changes

We tested the hypotheses that, in humans, changes in cardiac output (CO) and total peripheral vascular resistance (TPR) occurring in response to isometric handgrip exercise vary considerably among individuals and that those individual differences are related to differences in muscle metaboreflex and arterial baroreflex function. Thirty-nine healthy subjects performed a 1-min isometric handgrip exercise at 50% of maximal voluntary contraction. This was followed by a 4-min postexercise muscle ischemia (PEMI) period to selectively maintain activation of the muscle metaboreflex. All subjects showed increases in arterial pressure during exercise. Interindividual coefficients of variation (CVs) for the changes in CO and TPR between rest and exercise periods (CO: 95.1% and TPR: 87.8%) were more than twofold greater than CVs for changes in mean arterial pressure (39.7%). There was a negative correlation between CO and TPR responses during exercise ( r = −0.751, P < 0.01), but these CO and TPR responses correlated positively with the corresponding responses during PEMI ( r = 0.568 and 0.512, respectively, P < 0.01). The CO response during exercise did not correlate with PEMI-induced changes in an index of cardiac parasympathetic tone and cardiac baroreflex sensitivity. These findings demonstrate that the changes in CO and TPR that occur in response to isometric handgrip exercise vary considerably among individuals and that the two responses have an inverse relationship. They also suggest that individual differences in components of the pressor response are attributable in part to variations in muscle metaboreflex-mediated cardioaccelerator and vasoconstrictor responses.

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A cholinergic contribution to the circulatory responses evoked at the onset of handgrip exercise in humans

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00236.2014 ◽

2015 ◽

Vol 308 (7) ◽

pp. R597-R604 ◽

Cited By ~ 8

Author(s):

Lauro C. Vianna ◽

Paul J. Fadel ◽

Niels H. Secher ◽

James P. Fisher

Keyword(s):

Muscle Blood Flow ◽

Maximum Voluntary Contraction ◽

Handgrip Exercise ◽

Isometric Handgrip ◽

Cycling Exercise ◽

Cholinergic Mechanism ◽

Cholinergic Blockade ◽

Leg Cycling ◽

Isometric Handgrip Exercise ◽

Exercise In Humans

A cholinergic (muscarinic) contribution to the initial circulatory response to exercise in humans remains controversial. Herein, we posit that this may be due to exercise mode with a cholinergic contribution being important during isometric handgrip exercise, where the hyperemic response of the muscle is relatively small compared with the onset of leg cycling, where a marked increase in muscle blood flow rapidly occurs as a consequence of multiple redundant mechanisms. We recorded blood pressure (BP; brachial artery), stroke volume (pulse contour analysis), cardiac output, and systemic vascular resistance (SVR) in young healthy males, while performing either 20 s of isometric handgrip contraction at 40% maximum voluntary contraction ( protocol 1; n = 9) or 20 s of low-intensity leg cycling exercise ( protocol 2; n = 8, 42 ± 8 W). Exercise trials were conducted under control (no drug) conditions and following cholinergic blockade (glycopyrrolate). Under control conditions, isometric handgrip elicited an initial increase in BP (+5 ± 2 mmHg at 3 s and +3 ± 1 mmHg at 10 s, P < 0.05), while SVR dropped after 3 s (−27 ± 6% at 20 s; P < 0.05). Cholinergic blockade abolished the isometric handgrip-induced fall in SVR and, thereby, augmented the pressor response (+13 ± 3 mmHg at 10 s; P < 0.05 vs. control). In contrast, cholinergic blockade had a nonsignificant effect on changes in BP and SVR at the onset of leg cycling exercise. These findings suggest that a cholinergic mechanism is important for the BP and SVR responses at the onset of isometric handgrip exercise in humans.

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Isometric Handgrip Exercise Training Improves Spirometric Parameters and Pulmonary Capacity

Pathophysiology ◽

10.3390/pathophysiology28030022 ◽

2021 ◽

Vol 28 (3) ◽

pp. 328-338

Author(s):

Ogbutor Udoji Godsday ◽

Nwangwa Eze Kingsley ◽

Nwogueze Bartholomew Chukwuebuka ◽

Chukwuemeka Ephraim ◽

Ezunu Emmanuel ◽

...

Keyword(s):

Pulmonary Function ◽

Isometric Exercise ◽

Handgrip Exercise ◽

Isometric Handgrip ◽

Post Exercise ◽

Significant Difference ◽

Isometric Handgrip Exercise ◽

Group 3 ◽

Group 2 ◽

Group 1

Decline in normal physiological pulmonary function has been attributed to premorbid conditions such as prehypertension. Research evidence suggests that physical activity reduces age-related decline in pulmonary function and improves the efficiency of the lungs in prehypertensive patients. However, there is a scarcity of data evidence relating to isometric exercise and pulmonary function. Furthermore, the interrelationship between the intensity and duration of isometric exercise and pulmonary function in these patients is still uncertain. Therefore, this study was undertaken to investigate the effect of isometric handgrip exercise on pulmonary function capacity in adults with prehypertension. To determine the effectiveness of isometric handgrip exercise on pulmonary function capacity in adults with prehypertension. A quasi experiment using a pre- and post-exercise method was carried out in two out-patients hospital settings. The sample comprised 192 sedentary pre-hypertensive subjects, aged between 30–50 years, that were randomly distributed into three groups of 64 participants each. The subjects performed, for 24 consecutive days, an isometric handgrip exercise at 30% Maximum Voluntary Contraction (M.V.C.). At the end of the 24 days, group one (GP1) discontinued, while group two (GP2) continued the exercise protocol for another 24 consecutive days and group three (GP3) continued with the exercise protocol for another 24 consecutive days but at 50% M.V.C. Determinants of lung function (outcomes) were Forced Expiratory Volume in 1 s (FEV1), Forced Vital Capacity (FVC), FEV1/FVC Ratio and Peak Expiratory Flow Rate (PEFR). The study shows that there was no statistically significant difference in the pre- and post-exercise outcomes for FEV1, FVC, FEV1/FVC Ratio and PEFR after 24 days for group 1. In group 2, there was a statistically significant difference in the FVC [(mean = 0.12 ± 0.12), (p = 0.002)], FEV1 [(mean = 0.15 ± 0.17), (p = 0.003)] and PEF [(mean = 0.85 ± 0.35), (p = 0.001)] after 48 days. In group 3, there was a statistically significant difference (p = 0.001) in all the outcomes assessed after 48 days. There was a between groups difference in favour of group 2 compared with group 1 for outcomes of FEV1 [(mean = 0.142 ± 0.68), (p = 0.005)] and PEF [(mean = 0.83 ± 0.19), (p = 0.0031)]. There was statistically significant difference in favour of group 3 compared to group 2, by increasing the exercise intensity from 30% to 50% M.V.C., for outcomes of FVC [mean change = 0.10 ± 0.052), (p = 0.005)], FEV1/FVC [mean change = 3.18 ± 0.75), (p = 0.017)] and PEF [(mean change = 0.86 ± 0.35), (p = 0.001)] after 48 days. Isometric handgrip exercise (after 48 days at 30% to 50% M.V.C.) improves outcomes of pulmonary function capacity in adults with prehypertension. Meanwhile, duration and/or increase in intensity of the isometric effort significantly contributed to the affects attained.

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Association of changes of pulse wave velocity and augmentation index after isometric handgrip exercise with coronary lesion extent and revascularization

Clinical Hypertension ◽

10.1186/s40885-021-00163-5 ◽

2021 ◽

Vol 27 (1) ◽

Author(s):

Seong Taeg Kim ◽

Yeekyoung Ko ◽

Jong-Wook Beom ◽

Ki Yung Boo ◽

Jae-Geun Lee ◽

...

Keyword(s):

Arterial Stiffness ◽

Pulse Wave Velocity ◽

Iliac Artery ◽

Pulse Wave ◽

Augmentation Index ◽

Coronary Revascularization ◽

External Iliac Artery ◽

Handgrip Exercise ◽

Isometric Handgrip ◽

Isometric Handgrip Exercise

Abstract Background Arterial stiffness is associated with myocardial ischemia and incident coronary artery disease (CAD), and indexes of arterial stiffness are usually increased in patients with CAD. However, these indexes are often increased in elderly without CAD. Arterial stiffness in patients with CAD may become more evident after isometric handgrip exercise which increases systolic pressure and ventricular afterload. We investigated the association of the change of stiffness indexes after isometric handgrip exercise with the lesion extent of CAD and the necessity for coronary revascularization. Methods Patients who were scheduled a routine coronary angiography via a femoral artery were enrolled. Arterial waveforms were traced at aortic root and external iliac artery using coronary catheters at baseline and 3 min after handgrip exercise. Augmentation index (AIx) was measured on the recorded aortic pressure waveform, and pulse wave velocity (PWV) was calculated using the ECG-gated time difference of the upstroke of arterial waveforms and distance between aortic root and external iliac artery. Results Total 37 patients were evaluated. Both PWV and AIx increased after handgrip exercise. ΔPWV was significantly correlated with ΔAIx (r = 0.344, P = 0.037). Patients were divided into higher and lower ΔPWV or ΔAIx groups based on the median values of 0.4 m/sec and 3.3%, respectively. Patients with higher PWV had more 2- or 3-vessel CAD (69% vs. 27%, P = 0.034), and underwent percutaneous coronary intervention (PCI) more frequently (84% vs. 50%, P = 0.038), but higher ΔAIx was not associated with either the lesion extent or PCI. Area under curve (AUC) of ΔPWV in association with PCI by C-statistics was 0.70 (95% confidence interval [CI] 0.51–0.88; P = 0.056). In multiple logistic regression analysis, ΔPWV was significantly associated with PCI (odds ratio 7.78; 95% CI 1.26–48.02; P = 0.027). Conclusions Higher ΔPWV after isometric handgrip exercise was associated with the lesion extent of CAD and the necessity for coronary revascularization, but higher ΔAIx was not.

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Developmental Changes in Hemodynamic Responses and Cardiovagal Modulation during Isometric Handgrip Exercise

International Journal of Pediatrics ◽

10.1155/2010/153780 ◽

2010 ◽

Vol 2010 ◽

pp. 1-11 ◽

Cited By ~ 6

Author(s):

Styliani Goulopoulou ◽

Bo Fernhall ◽

Jill A. Kanaley

Keyword(s):

Mean Arterial Pressure ◽

Arterial Pressure ◽

Isometric Contraction ◽

Pressor Response ◽

Reflex Response ◽

Group Differences ◽

Handgrip Exercise ◽

Isometric Handgrip ◽

Isometric Handgrip Exercise ◽

Pressor Reflex

The purpose of this study was to examine differences in pressor response and cardiovagal modulation during isometric handgrip exercise (IHG) between children and adults. Beat-to-beat heart rate (HR) and blood pressure were measured in 23 prepubertal children and 23 adults at baseline and during IHG. Cardiovagal modulation was quantified by analysis of HR variability. Mean arterial pressure responses to IHG were greater in adults compared to children (P<.05) whereas there were no group differences in HR responses (P>.05). Children had a greater reduction in cardiovagal modulation in response to IHG compared to adults (P<.05). Changes in mean arterial pressure during IHG were correlated with baseline cardiovagal modulation and force produced during isometric contraction (P<.05). In conclusion, differences in pressor reflex response between children and adults cannot be solely explained by differences in autonomic modulation and appear to be associated with factors contributing to the force produced during isometric contraction.

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Effect of isometric handgrip exercise on intraocular pressure among healthy adult males

Comparative Exercise Physiology ◽

10.3920/cep200048 ◽

2020 ◽

pp. 1-6

Author(s):

S. Ezhilnila ◽

S. Brinda ◽

A. Meena ◽

P.J. Samuel

Keyword(s):

Intraocular Pressure ◽

Healthy Adult ◽

Lifestyle Modification ◽

Maximum Voluntary Contraction ◽

South Indian Population ◽

Adult Males ◽

Handgrip Exercise ◽

Isometric Handgrip ◽

South Indian ◽

Isometric Handgrip Exercise

Glaucoma is the main cause for irreversible blindness in India. The main determinant of glaucoma is raised intraocular pressure (IOP) which is influenced by many factors. One of the main factors is physical exercise. Objective of this study is to exhibit the effect of isometric handgrip exercise using Smedley’s handgrip dynamometer on IOP among young adult males in the south Indian population. In this quasi experimental study, 150 young healthy adult male subjects with ages between 15 to 40 years were selected on the basis of fulfilling our inclusion and exclusion criteria with the help of a questionnaire. Baseline IOP and maximum voluntary contraction (MVC) of the subjects were measured using non-contact tonometer and Smedley’s Handgrip Dynamometer, respectively. The subjects were instructed to hold the handgrip dynamometer with 20% of MVC in sustained manner for minimum 2 min or until fatigue sets in. IOP were measured on both eyes immediately and 15 min following exercise and IOP variation was analysed using paired t-test. A small but significant decrease in IOP was noted immediately as well as 15 min following exercise. Average fall in right eye was 1.75 mm Hg immediately and 2.14 mm Hg 15 min following exercise (P<0.01). The average fall in the left eye was 1.62 mm Hg immediately and 1.91 mm Hg after 15 min (P<0.01). Isometric handgrip exercise of the single upper limb showed significant reduction of IOP on both eyes following exercise and the decrease was much higher 15 min after exercise. This result can be extrapolated and clinically applied for glaucoma prevention and supplemented as lifestyle modification during glaucoma treatment.

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