Effects of Isometric Handgrip Protocol on Blood Pressure and Neurocardiac Modulation

Abstract

Isometric handgrip (IHG) remains a well-studied cardiovascular and autonomic stimulus, however the effects of rhythmic IHG protocols remain largely unknown. The purpose of this study was to investigate the acute effects of 4 IHG protocols on blood pressure (BP) and neurocardiac reactivity and recovery responses. 12 healthy older participants (70±5 yrs, ♀=4) each completed 4 bilateral 12-min protocols (sham, IHG1, IHG2, IHG3) on separate visits. IHG1, IHG2, and IHG3 consisted of 4×2-min, 8×1-min, and 16×30-s isometric contractions, respectively, each completed at 30% MVC, while sham consisted of 4×2-min contractions completed at 3% MVC. BP and neurocardiac modulation were assessed during and following each protocol. Systolic BP (SBP) reactivity was increased during IHG1 compared to IHG2 (p<0.05), IHG3 (p<0.05), and sham (p<0.01), although during recovery delta SBP was lower following IHG1 (p<0.01), IHG2 (p<0.01), and IHG3 (p<0.05), compared to sham. Sample entropy, a measure of nonlinear heart rate variability was reduced during IHG1 (p<0.01) and IHG2 (p<0.05), while increased following IHG1 (p<0.05) and IHG3 (p<0.05), compared to sham. In conclusion, recovery responses from rhythmic IHG appear independent of contraction and/or rest period frequency-duration relationships. Investigation of rhythmic IHG protocols warrants further examination.

Key words

isometric exercise - autonomic nervous system - heart rate variability - blood pressure

References

• 1 Barcroft H, Millen JL. The blood flow through muscle during sustained contraction.  J Physiol. 1939;  97 17-31
• 2 Freeman R. Assessment of cardiovascular autonomic function.  Clin Neurophysiol. 2006;  117 716-730
• 3 Gálvez JM, Alonso JP, Sangrador LA, Navarro G. Effect of muscle mass and intensity of isometric contraction on heart rate.  J Appl Physiol. 2000;  88 487-492
• 4 Gandevia SC, Hobbs SF. Cardiovascular responses to static exercise in man: central and reflex contributions.  J Physiol. 1990;  430 105-117
• 5 Goodwin GM, McCloskey DI, Mitchell JH. Cardiovascular and respiratory responses to changes in central command during isometric exercise at constant muscle tension.  J Physiol. 1972;  226 173-190
• 6 Goldberger AL, Amaral LAN, Glass L, Hausdorff JM, Ivanov PC, Mark RG, Mietus JE, Moody GB, Peng CK, Stanley HE. PhysioBank, PhysioToolkit, and PhysioNet: components of a new research resource for complex physiologic signals.  Circulation. 2000;  101 e215-e220
• 7 Hagerman I, Berglund M, Lorin M, Nowak J, Sylven C. Chaos-related deterministic regulation of heart rate variability in time- and frequency domains: effects of autonomic blockade and exercise.  Cardiovasc Res. 1996;  31 410-418
• 8 Harriss DJ, Atkinson G. International Journal of Sports Medicine – Ethical Standards in Sport and Exercise Science Research.  Int J Sports Med. 2009;  30 701-702
• 9 Heffernan KS, Sosnoff JJ, Jae SY, Gates GJ, Fernhall B. Acute resistance exercise reduces heart rate complexity and increases QTc interval.  Int J Sports Med. 2008;  29 289-293
• 10 Howden R, Lightfoot JT, Brown SJ, Swaine IL. The effects of isometric exercise training on resting blood pressure and orthostatic intolerance in humans.  Exp Physiol. 2004;  89 507-515
• 11 Karavirta L, Tulppo MP, Laaksonen DE, Nyman K, Laukkanen RT, Kinnunen H, Häkkinen A, Häkkinen K. Heart rate dynamics after combined endurance and strength training in older men.  Med Sci Sports Exerc. 2009;  41 1436-1443
• 12 Kaufman MP, Hayes SG. The exercise pressor reflex.  Clin Auton Res. 2002;  12 429-439
• 13 Kelley GA, Kelley KS. Isometric handgrip exercise and resting blood pressure: a meta-analysis of randomized controlled trials.  J Hypertens. 2010;  28 411-418
• 14 Kuusela TA, Jartti TT, Tahvanainen KU, Kaila TJ. Nonlinear methods of biosignal analysis in assessing terbutaline-induced heart rate and blood pressure changes.  Am J Physiol. 2002;  282 H773-H783
• 15 MacDougall JD, Tuxen D, Dale D, Moroz J, Sutton J. Arterial blood pressure response to heavy resistance exercise.  J Appl Physiol. 1985;  58 785-790
• 16 Mäkikallio TH, Tapanainen JM, Tulppo MP, Huikuri HV. Clinical applicability of heart rate variability analysis by methods based on nonlinear dynamics.  Card Electrophysiol Rev. 2002;  6 250-255
• 17 Mark AR, Victor R, Nerhed C, Wallin B. Microneurographic studies of the mechanisms of sympathetic nerve responses to static exercise in humans.  Circ Res. 1985;  57 461-469
• 18 McGowan CL, Levy AS, Millar PJ, Guzman JC, Morillo CA, McCartney N, Macdonald MJ. Acute vascular responses to isometric handgrip (IHG) exercise and the effects of training in persons medicated for hypertension.  Am J Physiol. 2006;  291 H1797-H1802
• 19 McGowan CL, Visocchi A, Faulkner M, Verduyn R, Rakobowchuk M, Levy AS, McCartney N, MacDonald MJ. Isometric handgrip training improves local flow-mediated dilation in medicated hypertensives.  Eur J Appl Physiol. 2007;  99 227-234
• 20 Millar PJ, Bray SR, MacDonald MJ, McCartney N. The hypotensive effects of isometric handgrip training using an inexpensive spring handgrip training device.  J Cardiopulm Rehabil Prev. 2008;  28 203-207
• 21 Millar PJ, Cotie LM, St Amand T, McCartney N, Ditor DS. Effects of autonomic blockade on nonlinear heart rate dynamics.  Clin Auton Res. 2010;  20 241-247
• 22 Millar PJ, MacDonald MJ, Bray SR, McCartney N. Isometric handgrip exercise improves acute neurocardiac regulation.  Eur J Appl Physiol. 2009;  107 509-515
• 23 Millar PJ, Rakobowchuk M, McCartney N, MacDonald MJ. Heart rate variability and nonlinear analysis of heart rate dynamics following single and multiple Wingate bouts.  Appl Physiol Nutr Metab. 2009;  34 875-883
• 24 Mitchell JH, Payne FC, Saltin B, Schibye B. The role of muscle mass in the cardiovascular responses to static contractions.  J Physiol (Lond). 1980;  309 45-54
• 25 Mitchell JH, Schibye B, Payne 3rd FC, Saltin B. Response of arterial blood pressure to static exercise in relation to muscle mass, force development, and electromyographic activity.  Circ Res. 1981;  48 I70-I75
• 26 Mitchell JH, Reeves Jr DR, Rogers HB, Secher NH, Victor RG. Autonomic blockade and cardiovascular responses to static exercise in partially curarized man.  J Physiol. 1989;  413 433-445
• 27 Notarius CF, Floras JS. Limitations of the use of spectral analysis of heart rate variability for the estimation of cardiac sympathetic activity in heart failure.  Europace. 2001;  3 29-38
• 28 Owen A, Wiles J, Swaine I. Effect of isometric exercise on resting blood pressure: a meta-analysis.  J Hum Hypertens. [Epub ahead of print Feb. 25, 2010]
• 29 Peng CK, Havlin S, Stanley HE, Goldberger AL. Quantification of scaling exponents and crossover phenomena in nonstationary heartbeat time series.  Chaos. 1995;  5 82-87
• 30 Penttilä J, Helminen A, Jartti T, Kuusela T, Huikuri HV, Tulppo MP, Scheinin H. Effect of cardiac vagal outflow on complexity and fractal correlation properties of heart rate dynamics.  Auton Autacoid Pharmacol. 2003;  23 173-179
• 31 Peters PG, Alessio HM, Hagerman AE, Ashton T, Nagy S, Wiley RL. Short-term isometric exercise reduces systolic blood pressure in hypertensive adults: possible role of reactive oxygen species.  Int J Cardiol. 2006;  110 199-205
• 32 Porta A, Gnecchi-Ruscone T, Tobaldini E, Guzzetti S, Furlan R, Montano N. Progressive decrease of heart period variability entropy-based complexity during graded head-up tilt.  J Appl Physiol. 2007;  103 1143-1149
• 33 Ray CA, Carrasco DI. Isometric handgrip training reduces arterial pressure at rest without changes in sympathetic nerve activity.  Am J Physiol. 2000;  279 H245-H249
• 34 Richman JS, Moorman JR. Physiological time-series analysis using approximate entropy and sample entropy.  Am J Physiol. 2000;  278 H2039-H2049
• 35 Rowell LB, O’Leary DS. Reflex control of the circulation during exercise: chemoreflexes and mechanoreflexes.  J Appl Physiol. 1990;  69 407-418
• 36 Seals DR. Influence of force on muscle and skin sympathetic nerve activity during sustained isometric contractions in humans.  J Physiol (Lond). 1993;  462 147-159
• 37 Stewart JM, Montgomery LD, Glover JL, Medow MS. Changes in regional blood volume and blood flow during static handgrip.  Am J Physiol. 2007;  292 H215-H223
• 38 Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology . Heart rate variability. Standards of measurement, physiological interpretation, and clinical use.  Circulation. 1996;  93 1043-1065
• 39 Taylor AC, McCartney N, Kamath MV, Wiley RL. Isometric training lowers resting blood pressure and modulates autonomic control.  Med Sci Sports Exerc. 2003;  35 251-256
• 40 Tulppo MP, Hughson RL, Mäkikallio TH, Airaksinen KE, Seppänen T, Huikuri HV. Effects of exercise and passive head-up tilt on fractal and complexity properties of heart rate dynamics.  Am J Physiol. 2001;  280 H1081-H1087
• 41 Wiley RL, Dunn CL, Cox RH, Hueppchen NA, Scott MS. Isometric exercise training lowers resting blood pressure.  Med Sci Sports Exerc. 1992;  24 749-754

Correspondence