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Ratchford SM, Broxterman RM, La Salle DT, Kwon OS, Hopkins PN, Richardson RS, Trinity JD. Obesity does not alter vascular function and handgrip exercise hemodynamics in middle-aged patients with hypertension. Am J Physiol Regul Integr Comp Physiol 2024; 326:R1-R9. [PMID: 37842741 PMCID: PMC11283903 DOI: 10.1152/ajpregu.00105.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 09/19/2023] [Accepted: 10/09/2023] [Indexed: 10/17/2023]
Abstract
Lifestyle modification including exercise training is often the first line of defense in the treatment of obesity and hypertension (HTN), however, little is known regarding how these potentially compounding disease states impact vasodilatory and hemodynamic responses at baseline and exercise. Therefore, this study sought to compare the impact of obesity on vascular function and hemodynamics at baseline and during handgrip (HG) exercise among individuals with HTN. Non-obese (13M/7F, 56 ± 16 yr, 25 ± 4 kg/m2) and obese (17M/4F, 50 ± 7 yr, 35 ± 4 kg/m2) middle-aged individuals with HTN forwent antihypertensive medication use for ≥2 wk before assessment of vascular function by brachial artery flow-mediated dilation (FMD) and exercise hemodynamics during progressive HG exercise at 15-30-45% maximal voluntary contraction (MVC). FMD was not different between Non-Obese (4.1 ± 1.7%) and Obese (5.2 ± 1.9%, P = 0.11). Systolic blood pressure (SBP) was elevated by ∼15% during the supine baseline and during HG exercise in the obese group. The blood flow response to HG exercise at 30% and 45% MVC was ∼20% greater (P < 0.05) in the obese group but not different after normalizing for the higher, albeit, nonsignificant differences in workloads (MVC: obese: 24 ± 5 kg, non-obese: 21 ± 5 kg, P = 0.11). Vascular conductance and the brachial artery shear-induced vasodilatory response during HG were not different between groups (P > 0.05). Taken together, despite elevated SBP during HG exercise, obesity does not lead to additional impairments in vascular function and peripheral exercising hemodynamics in patients with HTN. Obesity may not be a contraindication when prescribing exercise for the treatment of HTN among middle-aged adults, however, the elevated SBP should be appropriately monitored.NEW & NOTEWORTHY This study examined vascular function and handgrip exercise hemodynamics in obese and nonobese individuals with hypertension. Obesity, when combined with hypertension, was neither associated with additional vascular function impairments at baseline nor peripheral hemodynamics and vasodilation during exercise compared with nonobese hypertension. Interestingly, systolic blood pressure and pulse pressure were greater in the obese group during supine baseline and exercise. These findings should not be ignored and may be particularly important for rehabilitation strategies.
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Affiliation(s)
- Stephen M Ratchford
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veteran Affairs Medical Center, Salt Lake City, Utah, United States
| | - Ryan M Broxterman
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veteran Affairs Medical Center, Salt Lake City, Utah, United States
- Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah, United States
| | - D Taylor La Salle
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, United States
| | - Oh Sung Kwon
- Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah, United States
- Department of Kinesiology, University of Connecticut, Storrs, Connecticut, United States
| | - Paul N Hopkins
- Department of Internal Medicine, Division of Cardiovascular Genetics, University of Utah, Salt Lake City, Utah, United States
| | - Russell S Richardson
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veteran Affairs Medical Center, Salt Lake City, Utah, United States
- Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah, United States
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, United States
| | - Joel D Trinity
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veteran Affairs Medical Center, Salt Lake City, Utah, United States
- Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah, United States
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, United States
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2
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Hori A, Fukazawa A, Katanosaka K, Mizuno M, Hotta N. Mechanosensitive channels in the mechanical component of the exercise pressor reflex. Auton Neurosci 2023; 250:103128. [PMID: 37925831 DOI: 10.1016/j.autneu.2023.103128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 10/24/2023] [Accepted: 10/26/2023] [Indexed: 11/07/2023]
Abstract
The cardiovascular response is appropriately regulated during exercise to meet the metabolic demands of the active muscles. The exercise pressor reflex is a neural feedback mechanism through thin-fiber muscle afferents activated by mechanical and metabolic stimuli in the active skeletal muscles. The mechanical component of this reflex is referred to as skeletal muscle mechanoreflex. Its initial step requires mechanotransduction mediated by mechanosensors, which convert mechanical stimuli into biological signals. Recently, various mechanosensors have been identified, and their contributions to muscle mechanoreflex have been actively investigated. Nevertheless, the mechanosensitive channels responsible for this muscular reflex remain largely unknown. This review discusses progress in our understanding of muscle mechanoreflex under healthy conditions, focusing on mechanosensitive channels.
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Affiliation(s)
- Amane Hori
- College of Life and Health Sciences, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan; Japan Society for the Promotion of Science, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo 102-8472, Japan; Department of Applied Clinical Research, UT Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Ayumi Fukazawa
- Japan Society for the Promotion of Science, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo 102-8472, Japan; Department of Applied Clinical Research, UT Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Kimiaki Katanosaka
- College of Life and Health Sciences, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan
| | - Masaki Mizuno
- Department of Applied Clinical Research, UT Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Norio Hotta
- College of Life and Health Sciences, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan.
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Matsukawa K, Iwamoto GA, Mitchell JH, Mizuno M, Kim HK, Williamson JW, Smith SA. Exaggerated renal sympathetic nerve and pressor responses during spontaneously occurring motor activity in hypertensive rats. Am J Physiol Regul Integr Comp Physiol 2023; 324:R497-R512. [PMID: 36779670 DOI: 10.1152/ajpregu.00271.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
Stimulation of the mesencephalic locomotor region elicits exaggerated sympathetic nerve and pressor responses in spontaneously hypertensive rats (SHR) as compared with normotensive Wistar-Kyoto rats (WKY). This suggests that central command or its influence on vasomotor centers is augmented in hypertension. The decerebrate animal model possesses an ability to evoke intermittent bouts of spontaneously occurring motor activity (SpMA) and generates cardiovascular responses associated with the SpMA. It remains unknown whether the changes in sympathetic nerve activity and hemodynamics during SpMA are altered by hypertension. To test the hypothesis that the responses in renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP) during SpMA are exaggerated with hypertension, this study aimed to compare the responses in decerebrate, paralyzed SHR, WKY, and normotensive Sprague-Dawley (SD) rats. In all strains, an abrupt increase in RSNA occurred in synchronization with tibial motor discharge (an index of motor activity) and was followed by rises in MAP and heart rate. The centrally evoked increase in RSNA and MAP during SpMA was much greater (306 ± 110%) in SHR than WKY (187 ± 146%) and SD (165 ± 44%). Although resting baroreflex-mediated changes in RSNA were not different across strains, mechanically or pharmacologically induced elevations in MAP attenuated or abolished the RSNA increase during SpMA in WKY and SD but had no effect in SHR. It is likely that the exaggerated sympathetic nerve and pressor responses during SpMA in SHR are induced along a central command pathway independent of the arterial baroreflex and/or result from central command-induced inhibition of the baroreflex.
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Affiliation(s)
- Kanji Matsukawa
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, United States
- Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Gary A Iwamoto
- Department of Surgery, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Jere H Mitchell
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Masaki Mizuno
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, United States
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Han-Kyul Kim
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, United States
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Jon W Williamson
- Department of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Scott A Smith
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, United States
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States
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Franklin BA, Eijsvogels TM, Pandey A, Quindry J, Toth PP. Physical activity, cardiorespiratory fitness, and cardiovascular health: A clinical practice statement of the ASPC Part I: Bioenergetics, contemporary physical activity recommendations, benefits, risks, extreme exercise regimens, potential maladaptations. Am J Prev Cardiol 2022; 12:100424. [PMID: 36281324 PMCID: PMC9586848 DOI: 10.1016/j.ajpc.2022.100424] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 09/05/2022] [Accepted: 10/06/2022] [Indexed: 11/07/2022] Open
Abstract
Regular moderate-to-vigorous physical activity (PA) and increased levels of cardiorespiratory fitness (CRF) or aerobic capacity are widely promoted as cardioprotective measures in the primary and secondary prevention of atherosclerotic cardiovascular (CV) disease (CVD). Nevertheless, physical inactivity and sedentary behaviors remain a worldwide concern. The continuing coronavirus (COVID-19) pandemic has been especially devastating to patients with known or occult CVD since sitting time and recreational PA have been reported to increase and decrease by 28% and 33%, respectively. Herein, in this first of a 2-part series, we discuss foundational factors in exercise programming, with specific reference to energy metabolism, contemporary PA recommendations, the dose-response relationship of exercise as medicine, the benefits of regular exercise training, including the exercise preconditioning cardioprotective phenotype, as well as the CV risks of PA. Finally, we discuss the 'extreme exercise hypothesis,' specifically the potential maladaptations resulting from high-volume, high-intensity training programs, including accelerated coronary artery calcification and incident atrial fibrillation. The latter is commonly depicted by a reverse J-shaped or U-shaped curve. On the other hand, longevity data argue against this relationship, as elite endurance athletes live 3-6 years longer than the general population.
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Affiliation(s)
- Barry A. Franklin
- Preventive Cardiology and Cardiac Rehabilitation, Beaumont Health, Royal Oak, Michigan, USA
- Professor, Internal Medicine, Oakland University William Beaumont School of Medicine, Rochester, Michigan, USA
| | - Thijs M.H. Eijsvogels
- Radboud Institute for Health Sciences, Department of Physiology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Ambarish Pandey
- Department of Internal Medicine at UT Southwestern Medical Center, Dallas, TX, Michigan, USA
| | - John Quindry
- Integrative Physiology and Athletic Training, University of Montana, Missoula, Montana and International Heart Institute – St. Patrick's Hospital, Providence Medical Center, Missoula, Montana, USA
| | - Peter P. Toth
- CGH Medical Center, Sterling, IL, USA
- Ciccarone Center for the Prevention of Cardiovascular Disease, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Broxterman RM, La Salle DT, Zhao J, Reese VR, Kwon OS, Richardson RS, Trinity JD. Dietary Nitrate Supplementation and Small Muscle Mass Exercise Hemodynamics in Patients with Essential Hypertension. J Appl Physiol (1985) 2022; 133:506-516. [PMID: 35834624 PMCID: PMC9377785 DOI: 10.1152/japplphysiol.00218.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Exaggerated blood pressure and diminished limb hemodynamics during exercise in patients with hypertension often are not resolved by antihypertensive medications. We hypothesized that, independent of antihypertensive medication status, dietary nitrate supplementation would increase limb blood flow, decrease mean arterial pressure (MAP), and increase limb vascular conductance during exercise in patients with hypertension. Patients with hypertension either abstained from (n=14, Off-Meds) or continued (n=12, On-Meds) antihypertensive medications. Within each group, patients consumed (cross-over design) nitrate-rich or nitrate-depleted (placebo) beetroot juice for 3-days before performing handgrip (HG) and knee-extensor exercise (KE). Blood flow and MAP were measured using Doppler ultrasound and an automated monitor, respectively. Dietary nitrate increased plasma-[nitrite] Off-Meds and On-Meds. There were no significant effects of dietary nitrate on blood flow, MAP, or vascular conductance during HG in Off-Meds or On-Meds. For KE, dietary nitrate decreased MAP (mean±SD across all three exercise intensities, 118±14 vs. 122±14 mmHg, p=0.024) and increased vascular conductance (26.2±6.1 vs. 24.7±7.0 ml/min/mmHg, p=0.024), but did not affect blood flow for Off-Meds, with no effects On-Meds. Dietary nitrate-induced changes in blood flow (r=-0.67, p<0.001), MAP (r=-0.43, p=0.009), and vascular conductance (r=-0.64, p<0.001) during KE, but only vascular conductance (r=-0.35, p=0.039) during HG, were significantly related to the magnitude of placebo values, with no differentiation between groups. Thus, the effects of dietary nitrate on limb hemodynamics and MAP during exercise in patients with hypertension are dependent on the values at baseline, independent of antihypertensive medication status, and dependent on whether exercise was performed by the forearm or quadriceps.
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Affiliation(s)
- Ryan M Broxterman
- Geriatric Research, Education, and Clinical Center, Salt Lake City VAMC, Salt Lake City, UT, United States.,Department of Internal Medicine, University of Utah, Salt Lake City, Utah, United States.,Center on Aging, University of Utah, Salt Lake City, UT, United States
| | - D Taylor La Salle
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, United States
| | - Jia Zhao
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, United States
| | - Van R Reese
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, United States
| | - Oh Sung Kwon
- Department of Kinesiology, University of Connecticut, Storrs, CT, United States.,Department of Orthopedic Surgery and Center of Aging, University of Connecticut School of Medicine, Farmington, CT, United States
| | - Russell S Richardson
- Geriatric Research, Education, and Clinical Center, Salt Lake City VAMC, Salt Lake City, UT, United States.,Department of Internal Medicine, University of Utah, Salt Lake City, Utah, United States.,Center on Aging, University of Utah, Salt Lake City, UT, United States.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, United States
| | - Joel D Trinity
- Geriatric Research, Education, and Clinical Center, Salt Lake City VAMC, Salt Lake City, UT, United States.,Department of Internal Medicine, University of Utah, Salt Lake City, Utah, United States.,Center on Aging, University of Utah, Salt Lake City, UT, United States.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, United States
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6
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Haas A, Borsook D, Adler G, Freeman R. Stress, hypoglycemia, and the autonomic nervous system. Auton Neurosci 2022; 240:102983. [PMID: 35417827 DOI: 10.1016/j.autneu.2022.102983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 03/30/2022] [Accepted: 04/01/2022] [Indexed: 11/29/2022]
Abstract
Stress can be classified as either psychosocial or physiologic. Physiologic stress refers to stresses due to acute illness, trauma, pain, hypoglycemia, and sleep deprivation-much less is known regarding its health consequences. This review focuses on hypoglycemia as a model to further investigate physiological stress. Experimental mild to moderate hypoglycemia is a paradigmatic physiological stress that evokes autonomic, neuroendocrine, and immune responses. Hypoglycemic stress is an ideal model to examine the interactions and consequences of physiological stress on the autonomic nervous system. Acute hypoglycemia has been demonstrated to increase inflammatory markers, prolong QTc, and impair cardiac-vagal baroreflex sensitivity. Some of these consequences may not reverse completely when euglycemia is restored. For example, there is attenuation of the cardiac-vagal baroreflex, attenuation of the vascular sympathetic baroreflex (muscle sympathetic nerve activity response to transient hypotension), and attenuation of the catecholamine response to lower body negative pressure that is present the next day after hypoglycemia has resolved.
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Affiliation(s)
- Andrea Haas
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women's Hospital, Boston, MA, USA
| | - David Borsook
- Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Gail Adler
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women's Hospital, Boston, MA, USA
| | - Roy Freeman
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
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Wenner MM, Greaney JL, Matthews EL, McGinty S, Kaur J, Vongpatanasin W, Fadel PJ. Influence of Age and Estradiol on Sympathetic Nerve Activity Responses to Exercise in Women. Med Sci Sports Exerc 2022; 54:408-416. [PMID: 34711708 PMCID: PMC8847319 DOI: 10.1249/mss.0000000000002823] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Postmenopausal women (PMW) display exaggerated increases in blood pressure (BP) during exercise, yet the mechanism(s) involved remain unclear. Moreover, research on the impact of menopausal changes in estradiol on cardiovascular control during exercise are limited. Herein, we tested the hypothesis that sympathetic responses during exercise are augmented in PMWcompared with young women (YW), and estradiol administration attenuates these responses. METHODS Muscle sympathetic nerve activity (MSNA) and mean arterial pressure (MAP) were measured in 13 PMW (58 ± 1 yr) and 17 YW (22 ± 1 yr) during 2 min of isometric handgrip. Separately, MSNA and BP responses were measured during isometric handgrip in six PMW (53 ± 1 yr) before and after 1 month of transdermal estradiol (100 μg·d-1). A period of postexercise ischemia (PEI) to isolate muscle metaboreflex activation followed all handgrip bouts. RESULTS Resting MAP was similar between PMW and YW, whereas MSNA was greater in PMW (23 ± 3 vs 8 ± 1 bursts per minute; P < 0.05). During handgrip, the increases in MSNA (PMW Δ16 ± 2 vs YW Δ6 ± 1 bursts per minute; P < 0.05) and MAP (PMW Δ18 ± 2 vs YW Δ12 ± 2 mm Hg; P < 0.05) were greater in PMW and remained augmented during PEI. Estradiol administration decreased resting MAP but not MSNA in PMW. Moreover, MSNA (PMW (-E2) Δ27 ± 8 bursts per minute versus PMW (+E2) Δ12 ± 5 bursts per minute; P < 0.05) and MAP (Δ31 ± 8 mm Hg vs Δ20 ± 6 mm Hg; P < 0.05) responses during handgrip were attenuated in PMW after estradiol administration. Likewise, MAP responses during PEI were lower after estradiol. CONCLUSIONS These data suggest that PMW exhibit an exaggerated MSNA and BP response to isometric exercise, due in part to heightened metaboreflex activation. Furthermore, estradiol administration attenuated BP and MSNA responses to exercise in PMW.
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Affiliation(s)
- Megan M. Wenner
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE
| | - Jody L. Greaney
- Department of Kinesiology, The University of Texas at Arlington, Arlington, TX
| | - Evan L. Matthews
- Department of Exercise Science and Physical Education, Montclair State University, Montclair, NJ
| | - Shane McGinty
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE
| | - Jasdeep Kaur
- Department of Kinesiology and Health Education, University of Texas at Austin, Austin, TX
| | | | - Paul J. Fadel
- Department of Kinesiology, The University of Texas at Arlington, Arlington, TX
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Hori A, Hotta N, Fukazawa A, Estrada JA, Katanosaka K, Mizumura K, Sato J, Ishizawa R, Kim HK, Iwamoto GA, Vongpatanasin W, Mitchell JH, Smith SA, Mizuno M. Insulin potentiates the response to capsaicin in dorsal root ganglion neurons in vitro and muscle afferents ex vivo in normal healthy rodents. J Physiol 2022; 600:531-545. [PMID: 34967443 PMCID: PMC8810710 DOI: 10.1113/jp282740] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 12/23/2021] [Indexed: 02/03/2023] Open
Abstract
Systemic insulin administration evokes sympathoexcitatory actions, but the mechanisms underlying these observations are unknown. We reported that insulin sensitizes the response of thin-fibre primary afferents, as well as the dorsal root ganglion (DRG) that subserves them, to mechanical stimuli. However, little is known about the effects of insulin on primary neuronal responses to chemical stimuli. TRPV1, whose agonist is capsaicin (CAP), is widely expressed on chemically sensitive metaboreceptors and/or nociceptors. The aim of this investigation was to determine the effects of insulin on CAP-activated currents in small DRG neurons and CAP-induced action potentials in thin-fibre muscle afferents of normal healthy rodents. Additionally, we investigated whether insulin potentiates sympathetic nerve activity (SNA) responses to CAP. In whole-cell patch-clamp recordings from cultured mice DRG neurons in vitro, the fold change in CAP-activated current from pre- to post-application of insulin (n = 13) was significantly (P < 0.05) higher than with a vehicle control (n = 14). Similar results were observed in single-fibre recording experiments ex vivo as insulin potentiated CAP-induced action potentials compared to vehicle controls (n = 9 per group, P < 0.05). Furthermore, insulin receptor blockade with GSK1838705 significantly suppressed the insulin-induced augmentation in CAP-activated currents (n = 13) as well as the response magnitude of CAP-induced action potentials (n = 9). Likewise, the renal SNA response to CAP after intramuscular injection of insulin (n = 8) was significantly (P < 0.05) greater compared to vehicle (n = 9). The findings suggest that insulin potentiates TRPV1 responsiveness to CAP at the DRG and muscle tissue levels, possibly contributing to the augmentation in sympathoexcitation during activities such as physical exercise. KEY POINTS: Evidence suggests insulin centrally activates the sympathetic nervous system, and a chemical stimulus to tissues activates the sympathetic nervous system via thin fibre muscle afferents. Insulin is reported to modulate putative chemical-sensitive channels in the dorsal root ganglion neurons of these afferents. In the present study, it is demonstrated that insulin potentiates the responsiveness of thin fibre afferents to capsaicin at muscle tissue levels as well as at the level of dorsal root ganglion neurons. In addition, it is demonstrated that insulin augments the sympathetic nerve activity response to capsaicin in vivo. These data suggest that sympathoexcitation is peripherally mediated via insulin-induced chemical sensitization. The present study proposes a possible physiological role of insulin in the regulation of chemical sensitivity in somatosensory thin fibre muscle afferents.
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Affiliation(s)
- Amane Hori
- Graduate School of Life and Health Sciences, Chubu University, Kasugai 487-850, Japan;,Japan Society for the Promotion of Science, Tokyo 102-8472, Japan
| | - Norio Hotta
- Graduate School of Life and Health Sciences, Chubu University, Kasugai 487-850, Japan;,College of Life and Health Sciences, Chubu University, Kasugai 487-850, Japan
| | - Ayumi Fukazawa
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Juan A. Estrada
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Kimiaki Katanosaka
- Graduate School of Life and Health Sciences, Chubu University, Kasugai 487-850, Japan;,College of Life and Health Sciences, Chubu University, Kasugai 487-850, Japan
| | - Kazue Mizumura
- Department of Physiology, Nihon University School of Dentistry, Tokyo 101-8310, Japan
| | - Jun Sato
- Graduate School of Life and Health Sciences, Chubu University, Kasugai 487-850, Japan;,College of Life and Health Sciences, Chubu University, Kasugai 487-850, Japan
| | - Rie Ishizawa
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Han-Kyul Kim
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Gary A. Iwamoto
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Wanpen Vongpatanasin
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jere H. Mitchell
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Scott A. Smith
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Masaki Mizuno
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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9
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Mizuno M, Hotta N, Ishizawa R, Kim HK, Iwamoto G, Vongpatanasin W, Mitchell JH, Smith SA. The Impact of Insulin Resistance on Cardiovascular Control During Exercise in Diabetes. Exerc Sport Sci Rev 2021; 49:157-167. [PMID: 33965976 PMCID: PMC8195845 DOI: 10.1249/jes.0000000000000259] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Patients with diabetes display heightened blood pressure response to exercise, but the underlying mechanism remains to be elucidated. There is no direct evidence that insulin resistance (hyperinsulinemia or hyperglycemia) impacts neural cardiovascular control during exercise. We propose a novel paradigm in which hyperinsulinemia or hyperglycemia significantly influences neural regulatory pathways controlling the circulation during exercise in diabetes.
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Affiliation(s)
- Masaki Mizuno
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Norio Hotta
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
- College of Life and Health Sciences, Chubu University, Kasugai 487-850, Japan
| | - Rie Ishizawa
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Han-Kyul Kim
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Gary Iwamoto
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Wanpen Vongpatanasin
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Jere H. Mitchell
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Scott A. Smith
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
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Washio T, Suzuki K, Saito S, Watanabe H, Ando S, Brothers RM, Ogoh S. Effects of acute interval handgrip exercise on cognitive performance. Physiol Behav 2021; 232:113327. [PMID: 33493545 DOI: 10.1016/j.physbeh.2021.113327] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 01/12/2021] [Accepted: 01/19/2021] [Indexed: 12/16/2022]
Abstract
Previous studies have reported that even a single bout of dynamic exercise improves cognitive performance. However, the acute effect of the interval handgrip (HG) exercise protocol, which is effective in reducing resting blood pressure, on cognitive performance is poorly understood. Cognitive performance was assessed in 17 young healthy subjects before and after a resting control (e.g., time control) and the interval HG exercise (Exercise), which consisted of four trials of 2-min HG exercise at 25% of maximum voluntary contraction with 3-min recovery in between each trial. Mean arterial blood pressure (MAP) and middle cerebral artery blood velocity (MCA V) were measured continuously throughout the experiment. Memory recognition and executive function were assessed using memory recognition and Go/No-Go tasks, respectively. During interval HG exercise, MAP and mean MCA V increased from the resting baseline condition (both P < 0.049) and returned to the resting baseline levels during recovery after the interval HG exercise (both P = 1.000). The reaction time and performance accuracy of the memory recognition task did not change in either the time control condition or Exercise condition (P = 0.514 and P = 0.414 respectively). However, the changes in reaction time of Go/No-Go task from the baseline in Exercise condition was significantly shorter than that in time-control condition (P = 0.004) without affecting performance accuracy (P = 0.482). The results of the present study show that an acute interval HG exercise could improve the processing speed in executive function despite no post-exercise improvement in hemodynamic parameters in young healthy subjects. These findings suggest that the interval HG exercise is a useful exercise mode that can be expected to have a positive effect on the processing speed in executive function regardless of cardiovascular adaptation to exercise.
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Affiliation(s)
- Takuro Washio
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan; Research Fellow of Japan Society for the Promotion of Science, Tokyo, Japan
| | - Kazuya Suzuki
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan
| | - Shotaro Saito
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan
| | - Hironori Watanabe
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan
| | - Soichi Ando
- Graduate School of Informatics and Engineering, The University of Electro-Communications, Tokyo, Japan
| | - R Matthew Brothers
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
| | - Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan.
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11
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Ishizawa R, Kim HK, Hotta N, Iwamoto GA, Mitchell JH, Smith SA, Vongpatanasin W, Mizuno M. TRPV1 (Transient Receptor Potential Vanilloid 1) Sensitization of Skeletal Muscle Afferents in Type 2 Diabetic Rats With Hyperglycemia. Hypertension 2021; 77:1360-1371. [PMID: 33641357 DOI: 10.1161/hypertensionaha.120.15672] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Rie Ishizawa
- From the Departments of Applied Clinical Research (R.I., S.A.S., M.M.), University of Texas Southwestern Medical Center, Dallas
| | - Han-Kyul Kim
- Internal Medicine (H.-K.K., J.H.M., S.A.S., W.V., M.M.), University of Texas Southwestern Medical Center, Dallas
| | - Norio Hotta
- College of Life and Health Sciences, Chubu University, Kasugai, Japan (N.H.)
| | - Gary A Iwamoto
- Cell Biology (G.A.I.), University of Texas Southwestern Medical Center, Dallas
| | - Jere H Mitchell
- Internal Medicine (H.-K.K., J.H.M., S.A.S., W.V., M.M.), University of Texas Southwestern Medical Center, Dallas
| | - Scott A Smith
- From the Departments of Applied Clinical Research (R.I., S.A.S., M.M.), University of Texas Southwestern Medical Center, Dallas.,Internal Medicine (H.-K.K., J.H.M., S.A.S., W.V., M.M.), University of Texas Southwestern Medical Center, Dallas
| | - Wanpen Vongpatanasin
- Internal Medicine (H.-K.K., J.H.M., S.A.S., W.V., M.M.), University of Texas Southwestern Medical Center, Dallas
| | - Masaki Mizuno
- From the Departments of Applied Clinical Research (R.I., S.A.S., M.M.), University of Texas Southwestern Medical Center, Dallas.,Internal Medicine (H.-K.K., J.H.M., S.A.S., W.V., M.M.), University of Texas Southwestern Medical Center, Dallas
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12
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Augmented Hemodynamic Responses in Obese Young Men during Dynamic Exercise: Role of the Muscle Metaboreflex. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17197321. [PMID: 33036416 PMCID: PMC7579031 DOI: 10.3390/ijerph17197321] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/04/2020] [Accepted: 10/05/2020] [Indexed: 02/03/2023]
Abstract
Studies found that cardiovascular responses to exercise are enhanced in individuals with obesity and are associated with a greater cardiac output (CO) response compared to normal weight controls. However, the mechanisms underlying these altered responses during dynamic exercise are not clear. We investigated whether the cardiovascular responses mediated by the muscle metaboreflex (MMR) activation are augmented in obese men during both static and dynamic exercise. Twenty males (10 obese (OG) and 10 non-obese (NOG)) were studied. Changes in CO, mean arterial pressure (MAP), and total vascular conductance (TVC) were compared between the two groups during dynamic handgrip exercise (DHE), post-exercise muscular ischemia (PEMI), and dynamic exercise corresponding to 40%, 60% and 80% workloads. Subjects completed 2 min of DHE at 30% of MVC, followed by 2 min of PEMI. MAP, CO, and TVC responses to DHE and dynamic exercise were significantly higher in OG, whereas there were no differences during PEMI. Increases in CO and MAP during mild to heavy dynamic exercise were seen in both groups, but the changes in these variables were greater in the OG. There were no significant differences in TVC between the two groups. Compared to NOG, the augmented blood pressure response to DHE and dynamic exercise in OG was associated with a greater increase in CO. Thus, the augmented CO and MAP responses were not associated with the activation of the MMR. Consequently, additional factors specific to obesity, such as the mechanoreflex, may have been involved.
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13
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Grotle AK, Macefield VG, Farquhar WB, O'Leary DS, Stone AJ. Recent advances in exercise pressor reflex function in health and disease. Auton Neurosci 2020; 228:102698. [PMID: 32861944 DOI: 10.1016/j.autneu.2020.102698] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/01/2020] [Accepted: 07/02/2020] [Indexed: 01/11/2023]
Abstract
Autonomic alterations at the onset of exercise are critical to redistribute cardiac output towards the contracting muscles while preventing a fall in arterial pressure due to excessive vasodilation within the contracting muscles. Neural mechanisms responsible for these adjustments include central command, the exercise pressor reflex, and arterial and cardiopulmonary baroreflexes. The exercise pressor reflex evokes reflex increases in sympathetic activity to the heart and systemic vessels and decreases in parasympathetic activity to the heart, which increases blood pressure (BP), heart rate, and total peripheral resistance through vasoconstriction of systemic vessels. In this review, we discuss recent advancements in our understanding of exercise pressor reflex function in health and disease. Specifically, we discuss emerging evidence suggesting that sympathetic vasoconstrictor drive to the contracting and non-contracting skeletal muscle is differentially controlled by central command and the metaboreflex in healthy conditions. Further, we discuss evidence from animal and human studies showing that cardiovascular diseases, including hypertension, diabetes, and heart failure, lead to an altered exercise pressor reflex function. We also provide an update on the mechanisms thought to underlie this altered exercise pressor reflex function in each of these diseases. Although these mechanisms are complex, multifactorial, and dependent on the etiology of the disease, there is a clear consensus that several mechanisms are involved. Ultimately, approaches targeting these mechanisms are clinically significant as they provide alternative therapeutic strategies to prevent adverse cardiovascular events while also reducing symptoms of exercise intolerance.
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Affiliation(s)
- Ann-Katrin Grotle
- Department of Kinesiology and Health Education, The University of Texas at Austin, Austin, TX, United States of America
| | | | - William B Farquhar
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, United States of America
| | - Donal S O'Leary
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, United States of America
| | - Audrey J Stone
- Department of Kinesiology and Health Education, The University of Texas at Austin, Austin, TX, United States of America.
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14
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Hotta N, Hori A, Okamura Y, Baba R, Watanabe H, Sugawara J, Vongpatanasin W, Wang J, Kim HK, Ishizawa R, Iwamoto GA, Mitchell JH, Smith SA, Mizuno M. Insulin resistance is associated with an exaggerated blood pressure response to ischemic rhythmic handgrip exercise in nondiabetic older adults. J Appl Physiol (1985) 2020; 129:144-151. [PMID: 32584663 DOI: 10.1152/japplphysiol.00247.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Patients with type 2 diabetes display an exaggerated pressor response to exercise. However, evidence supporting the association between the magnitude of the pressor response to exercise and insulin resistance-related factors including hemoglobin A1c (HbA1c) or homeostatic model assessment of insulin resistance (HOMA-IR) in nondiabetic subjects has remained sparse and inconclusive. Thus we investigated the relationship between cardiovascular responses to exercise and insulin resistance-related factors in nondiabetic healthy men (n = 23) and women (n = 22) above 60 yr old. We measured heart rate (HR) and blood pressure (BP) responses during: isometric handgrip (IHG) exercise of 30% maximal voluntary contraction, a period of skeletal muscle ischemia (SMI) induced by tourniqueting the arm after IHG, and rhythmic dynamic handgrip (DHG) exercise during SMI. Greater diastolic BP (DBP) responses to DHG with SMI was associated with male sex (r = 0.44, P = 0.02) and higher HbA1c (r = 0.33, P = 0.03), heart-ankle pulse wave velocity (haPWV) (r = 0.45, P < 0.01), and resting systolic BP (SBP) (r = 0.36, P = 0.02). HbA1c persisted as a significant determinant explaining the variance in the DBP response to DHG with SMI in multivariate models despite adjustment for sex, haPWV, and resting SBP. It was also determined that the DBP response to DHG with SMI in a group in which HOMA-IR was abnormal (Δ33 ± 3 mmHg) was significantly higher than that of groups in which HOMA-IR was at intermediate (Δ20 ± 4 mmHg) and normal (Δ23 ± 2 mmHg) levels. These data suggest that even in nondiabetic older adults, insulin resistance is related to an exaggerated pressor response to exercise especially when performed under ischemic conditions.NEW & NOTEWORTHY The diastolic blood pressure response to rhythmic dynamic handgrip exercise under ischemic conditions was demonstrated to be correlated with insulin resistance-related factors in nondiabetic older adults. This finding provides important insight to the prescription of exercise in this particular patient population as the blood pressure response to exercise, especially under ischemic conditions, could be exaggerated to nonsafe levels.
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Affiliation(s)
- Norio Hotta
- College of Life and Health Sciences, Chubu University, Kasugai, Japan
| | - Amane Hori
- Graduate School of Life and Health Sciences, Chubu University, Kasugai, Japan
| | - Yukiko Okamura
- College of Life and Health Sciences, Chubu University, Kasugai, Japan
| | - Reizo Baba
- College of Life and Health Sciences, Chubu University, Kasugai, Japan
| | - Hidehiro Watanabe
- Department of Rehabilitation, Tokai Memorial Hospital, Kasugai, Japan
| | - Jun Sugawara
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
| | - Wanpen Vongpatanasin
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Jijia Wang
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Han-Kyul Kim
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Rie Ishizawa
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Gary A Iwamoto
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Jere H Mitchell
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Scott A Smith
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Masaki Mizuno
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas
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15
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Raven PB, Young BE, Fadel PJ. Arterial Baroreflex Resetting During Exercise in Humans: Underlying Signaling Mechanisms. Exerc Sport Sci Rev 2020; 47:129-141. [PMID: 30921029 DOI: 10.1249/jes.0000000000000190] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The arterial baroreflex (ABR) resets during exercise in an intensity-dependent manner to operate around a higher blood pressure with maintained sensitivity. This review provides a historical perspective of ABR resetting and the involvement of other neural reflexes in mediating exercise resetting. Furthermore, we discuss potential underlying signaling mechanisms that may contribute to exercise ABR resetting in physiological and pathophysiological conditions.
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Affiliation(s)
- Peter B Raven
- Department of Integrative Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth
| | - Benjamin E Young
- Department of Kinesiology, University of Texas at Arlington, Arlington, TX
| | - Paul J Fadel
- Department of Kinesiology, University of Texas at Arlington, Arlington, TX
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16
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Ishizawa R, Kim HK, Hotta N, Iwamoto GA, Vongpatanasin W, Mitchell JH, Smith SA, Mizuno M. Skeletal Muscle Reflex-Induced Sympathetic Dysregulation and Sensitization of Muscle Afferents in Type 1 Diabetic Rats. Hypertension 2020; 75:1072-1081. [PMID: 32063060 DOI: 10.1161/hypertensionaha.119.14118] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The blood pressure response to exercise is exaggerated in the type 1 diabetes mellitus (T1DM). An overactive exercise pressor reflex (EPR) contributes to the potentiated pressor response. However, the mechanism(s) underlying this abnormal EPR activity remains unclear. This study tested the hypothesis that the heightened blood pressure response to exercise in T1DM is mediated by EPR-induced sympathetic overactivity. Additionally, the study examined whether the single muscle afferents are sensitized by PKC (protein kinase C) activation in this disease. Sprague-Dawley rats were intraperitoneally administered either 50 mg/kg streptozotocin (T1DM) or saline (control). At 1 to 3 weeks after administration, renal sympathetic nerve activity and mean arterial pressure responses to activation of the EPR, mechanoreflex, and metaboreflex were measured in decerebrate animals. Action potential responses to mechanical and chemical stimulation were determined in group IV afferents with pPKCα (phosphorylated-PKCα) levels assessed in dorsal root ganglia. Compared with control, EPR (58±18 versus 96±33%; P<0.05), mechanoreflex (21±13 versus 51±20%; P<0.05), and metaboreflex (40±20 versus 88±39%; P<0.01) activation in T1DM rats evoked significant increases in renal sympathetic nerve activity as well as mean arterial pressure. The response of group IV afferents to mechanical (18±24 versus 61±45 spikes; P<0.01) and chemical (0.3±0.4 versus 1.6±0.8 Hz; P<0.01) stimuli were significantly greater in T1DM than control. T1DM rats showed markedly increased pPKCα levels in dorsal root ganglia compared with control. These data suggest that in T1DM, abnormally muscle reflex-evoked increases in sympathetic activity mediate exaggerations in blood pressure. Further, sensitization of muscle afferents, potentially via PKC activation, may contribute to this abnormal circulatory responsiveness.
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Affiliation(s)
- Rie Ishizawa
- From the Department of Applied Clinical Research (R.I., N.H., S.A.S., M.M.), University of Texas Southwestern Medical Center, Dallas
| | - Han-Kyul Kim
- Department of Internal Medicine (H.-K.K., W.V., J.H.M., S.A.S., M.M.), University of Texas Southwestern Medical Center, Dallas
| | - Norio Hotta
- From the Department of Applied Clinical Research (R.I., N.H., S.A.S., M.M.), University of Texas Southwestern Medical Center, Dallas.,College of Life and Health Sciences, Chubu University, Kasugai, Japan (N.H.)
| | - Gary A Iwamoto
- Department of Cell Biology (G.A.I.), University of Texas Southwestern Medical Center, Dallas
| | - Wanpen Vongpatanasin
- Department of Internal Medicine (H.-K.K., W.V., J.H.M., S.A.S., M.M.), University of Texas Southwestern Medical Center, Dallas
| | - Jere H Mitchell
- Department of Internal Medicine (H.-K.K., W.V., J.H.M., S.A.S., M.M.), University of Texas Southwestern Medical Center, Dallas
| | - Scott A Smith
- From the Department of Applied Clinical Research (R.I., N.H., S.A.S., M.M.), University of Texas Southwestern Medical Center, Dallas.,Department of Internal Medicine (H.-K.K., W.V., J.H.M., S.A.S., M.M.), University of Texas Southwestern Medical Center, Dallas
| | - Masaki Mizuno
- From the Department of Applied Clinical Research (R.I., N.H., S.A.S., M.M.), University of Texas Southwestern Medical Center, Dallas.,Department of Internal Medicine (H.-K.K., W.V., J.H.M., S.A.S., M.M.), University of Texas Southwestern Medical Center, Dallas
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17
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Ratchford SM, Broxterman RM, La Salle DT, Kwon OS, Park SY, Hopkins PN, Richardson RS, Trinity JD. Salt restriction lowers blood pressure at rest and during exercise without altering peripheral hemodynamics in hypertensive individuals. Am J Physiol Heart Circ Physiol 2019; 317:H1194-H1202. [PMID: 31584837 PMCID: PMC7199224 DOI: 10.1152/ajpheart.00431.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 10/02/2019] [Accepted: 10/02/2019] [Indexed: 01/22/2023]
Abstract
Dietary salt restriction is a well-established approach to lower blood pressure and reduce cardiovascular disease risk in hypertensive individuals. However, little is currently known regarding the effects of salt restriction on central and peripheral hemodynamic responses to exercise in those with hypertension. Therefore, this study sought to determine the impact of salt restriction on the central and peripheral hemodynamic responses to static-intermittent handgrip (HG) and dynamic single-leg knee extension (KE) exercise in individuals with hypertension. Twenty-two subjects (14 men and 8 women, 51 ± 10 yr, 173 ± 11 cm, 99 ± 23 kg) forewent their antihypertensive medication use for at least 2 wk before embarking on a 5-day liberal salt (LS: 200 mmol/day) diet followed by a 5-day restricted salt (RS: 10 mmol/day) diet. Subjects were studied at rest and during static intermittent HG exercise at 15, 30, and 45% of maximal voluntary contraction and KE exercise at 40, 60, and 80% of maximum KE work rate. Salt restriction lowered resting systolic blood pressure (supine: -12 ± 12 mmHg, seated: -17 ± 12 mmHg) and diastolic blood pressure (supine: -3 ± 9 mmHg, seated: -5 ± 7 mmHg, P < 0.05). Despite an ~8 mmHg lower mean arterial blood pressure during both HG and KE exercise following salt restriction, neither central nor peripheral hemodynamics were altered. Therefore, salt restriction can lower blood pressure during exercise in subjects with hypertension, reducing the risk of cardiovascular events, without impacting central and peripheral hemodynamics during either arm or leg exercise.NEW & NOTEWORTHY This is the first study to examine the potential blood pressure-lowering benefit of a salt-restrictive diet in individuals with hypertension without any deleterious effects of exercising blood flow. While mean arterial pressure decreased by ~8 mmHg following salt restriction, these findings provide evidence for salt restriction to provide protective effects of reducing blood pressure without inhibiting central or peripheral hemodynamics required to sustain arm or leg exercise in subjects with hypertension.
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Affiliation(s)
- Stephen M Ratchford
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah
- Department of Health and Exercise Science, Appalachian State University, Boone, North Carolina
| | - Ryan M Broxterman
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah
- Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah
| | - D Taylor La Salle
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | - Oh Sung Kwon
- Department of Kinesiology, University of Connecticut, Storrs, Connecticut
| | - Song-Young Park
- School of Health and Kinesiology, University of Nebraska, Omaha, Nebraska
| | - Paul N Hopkins
- Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah
- Division of Cardiovascular Genetics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah
| | - Russell S Richardson
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah
- Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | - Joel D Trinity
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah
- Division of Geriatrics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
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18
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Smith JR, Koepp KE, Berg JD, Akinsanya JG, Olson TP. Influence of Sex, Menstrual Cycle, and Menopause Status on the Exercise Pressor Reflex. Med Sci Sports Exerc 2019; 51:874-881. [PMID: 30986812 DOI: 10.1249/mss.0000000000001877] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
In this review, we highlight the underlying mechanisms responsible for the sex differences in the exercise pressor reflex (EPR), and, importantly, the impact of sex hormones and menopausal status. The EPR is attenuated in premenopausal women compared with age-matched men. Specifically, activation of the metaboreflex (a component of the EPR) results in attenuated increases in blood pressure and sympathetic vasomotor outflow compared with age-matched men. In addition, premenopausal women exhibit less transduction of sympathetic outflow to the peripheral vasculature than men. In stark contrast, postmenopausal women exhibit an augmented EPR arising from exaggerated metaboreflex-induced autonomic and cardiovascular reflexes. We propose that metaboreflex-induced autonomic and cardiovascular changes associated with menopause majorly contribute to the elevated blood pressure response during dynamic exercise in postmenopausal women. In addition, we discuss the potential mechanisms by which sex hormones in premenopausal women may impact the EPR as well as metaboreflex.
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Affiliation(s)
- Joshua R Smith
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN
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19
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Pigolkin YI, Shilova MA, Zakharov SN, Sereda AP, Zholinskiy AV, Kruglova IV, Shigeev SV. [The sudden death among the young persons under effect of the different forms of physical loads]. Sud Med Ekspert 2019; 62:50-55. [PMID: 30724895 DOI: 10.17116/sudmed20196201150] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The present review of the literature publications concerns the problem of sudden death (SD) among the young persons under effect of the different forms of physical loads. The statistical data on the frequency of sudden death are presented together with information about risk factors of SD, the morphological substrates and structural changes that promote death coming. The cases of sudden death among the young persons associated with the amateur sports activities and the professional sport of records are presented. The role of physical exercises and psycho-emotional stresses in the development of the terminal processes is considered with special reference to the risk factors and genetic predisposition to sudden cardiac death, largely among male athletes. The questions of sudden death in connection with cardiac pathologies as its main causes are discussed.
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Affiliation(s)
- Yu I Pigolkin
- Department of Forensic Medicine, I.M. Sechenov First Moscow State Medical University, Ministry of Health of the Russia, Moscow, Russia, 119435
| | - M A Shilova
- Department of Forensic Medicine, I.M. Sechenov First Moscow State Medical University, Ministry of Health of the Russia, Moscow, Russia, 119435
| | - S N Zakharov
- Department of Forensic Medicine, I.M. Sechenov First Moscow State Medical University, Ministry of Health of the Russia, Moscow, Russia, 119435
| | - A P Sereda
- Centre for Sports Medicine, Russian Federal Medico-Biological Agency of the Russia, Moscow, Russia, 123182
| | - A V Zholinskiy
- Centre for Sports Medicine, Russian Federal Medico-Biological Agency of the Russia, Moscow, Russia, 123182
| | - I V Kruglova
- Centre for Sports Medicine, Russian Federal Medico-Biological Agency of the Russia, Moscow, Russia, 123182
| | - S V Shigeev
- Bureau of Forensic Medical Expertise, Moscow Health, Moscow, Russia, 115516
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20
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Kim HK, Hotta N, Ishizawa R, Iwamoto GA, Vongpatanasin W, Mitchell JH, Smith SA, Mizuno M. Exaggerated pressor and sympathetic responses to stimulation of the mesencephalic locomotor region and exercise pressor reflex in type 2 diabetic rats. Am J Physiol Regul Integr Comp Physiol 2019; 317:R270-R279. [PMID: 31091155 DOI: 10.1152/ajpregu.00061.2019] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The cardiovascular responses to exercise are potentiated in patients with type 2 diabetes mellitus (T2DM). However, the underlying mechanisms causing this abnormality remain unknown. Central command (CC) and the exercise pressor reflex (EPR) are known to contribute significantly to cardiovascular control during exercise. Thus these neural signals are viable candidates for the generation of the abnormal circulatory regulation in this disease. We hypothesized that augmentations in CC as well as EPR function contribute to the heightened cardiovascular responses during exercise in T2DM. To test this hypothesis, changes in mean arterial pressure (MAP) and renal sympathetic nerve activity (RSNA) in response to electrical stimulation of mesencephalic locomotor region (MLR), a putative component of the central command pathway, and activation of the EPR, evoked by electrically induced hindlimb muscle contraction, were examined in decerebrate animals. Sprague-Dawley rats were given either a normal diet (control) or a high-fat diet (14-16 wk) in combination with two low doses (35 mg/kg week 1, 25 mg/kg week 2) of streptozotocin (T2DM). The changes in MAP and RSNA responses to MLR stimulation were significantly greater in T2DM compared with control (2,739 ± 123 vs. 1,298 ± 371 mmHg/s, 6,326 ± 1,621 vs. 1,390 ± 277%/s, respectively, P < 0.05). Similarly, pressor and sympathetic responses to activation of the EPR in diabetic animals were significantly augmented compared with control animals (436 ± 74 vs. 134 ± 44 mmHg/s, 645 ± 135 vs. 139 ± 65%/s, respectively, P < 0.05). These findings provide the first evidence that CC and the EPR may generate the exaggerated rise in sympathetic activity and blood pressure during exercise in T2DM.
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Affiliation(s)
- Han-Kyul Kim
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Norio Hotta
- Department of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, Texas.,College of Life and Health Sciences, Chubu University, Kasugai, Japan
| | - Rie Ishizawa
- Department of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Gary A Iwamoto
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Wanpen Vongpatanasin
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Jere H Mitchell
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Scott A Smith
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Masaki Mizuno
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, Texas
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21
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Dombrowski M, Mannozzi J, O'Leary DS. Neural Control of Cardiovascular Function During Exercise in Hypertension. Front Physiol 2019; 9:1829. [PMID: 30618837 PMCID: PMC6306405 DOI: 10.3389/fphys.2018.01829] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 12/06/2018] [Indexed: 11/28/2022] Open
Abstract
During both static and dynamic exercise hypertensive subjects can experience robust increases in arterial pressure to such an extent that heavy exercise is often not recommended in these patients due to the dangerously high levels of blood pressure sometimes observed. Currently, the mechanisms mediating this cardiovascular dysfunction during exercise in hypertension are not fully understood. The major reflexes thought to mediate the cardiovascular responses to exercise in normotensive healthy subjects are central command, arterial baroreflex and responses to stimulation of skeletal muscle mechano-sensitive and metabo-sensitive afferents. This review will summarize our current understanding of the roles of these reflexes and their interactions in mediating the altered cardiovascular responses to exercise observed in hypertension. We conclude that much work is needed to fully understand the mechanisms mediating excessive pressor response to exercise often seen in hypertensive patients.
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Affiliation(s)
- Maryetta Dombrowski
- Department of Physiology and Cardiovascular Research Institute, Wayne State University School of Medicine, Detroit, MI, United States
| | - Joseph Mannozzi
- Department of Physiology and Cardiovascular Research Institute, Wayne State University School of Medicine, Detroit, MI, United States
| | - Donal S O'Leary
- Department of Physiology and Cardiovascular Research Institute, Wayne State University School of Medicine, Detroit, MI, United States
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Andrade DDM, Amaral JF, Trevizan PF, Toschi-Dias E, Silva LPD, Laterza MC, Martinez DG. Anxiety increases the blood pressure response during exercise. MOTRIZ: REVISTA DE EDUCACAO FISICA 2019. [DOI: 10.1590/s1980-6574201900030016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2023] Open
Affiliation(s)
| | | | | | - Edgar Toschi-Dias
- Universidade Metodista de São Paulo, Brasil; Universidade Ibirapuera, Brasil
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Grafe K, Bendick P, Burr M, Boura J, Franklin BA. Effects of Resistance Training on Vascular and Hemodynamic Responses in Patients With Coronary Artery Disease. RESEARCH QUARTERLY FOR EXERCISE AND SPORT 2018; 89:457-464. [PMID: 30300089 DOI: 10.1080/02701367.2018.1519385] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
PURPOSE The purpose of this study was to determine the impact of adjunctive resistance training (RT) in aerobically trained patients with coronary artery disease on systolic blood pressure (SBP), heart rate (HR), rating of perceived exertion (RPE; using the traditional 6-to-20 scale), and rate-pressure product (RPP) responses to lifting fixed submaximal workloads. Additionally, pretest and posttest RT measures of brachial artery reactivity were obtained. METHOD Fifteen patients with coronary artery disease (Mage = 66.1 ± 5.1 years) who were already performing regular aerobic exercise completed an adjunctive 12-week progressive RT program. Prior to and immediately after the training period, hemodynamic responses and RPE were obtained while participants performed one set of exercises including the bicep curl (BC), shoulder press (SP), and leg press (LP) at individually determined fixed submaximal loads, using ~ 60% to 80% of estimated maximal voluntary contraction. Vascular function was assessed by flow-mediated vasodilation (FMD) testing before and after training. RESULTS Attenuated hemodynamic and RPE responses for all variables were observed. Meaningful changes were attained for RPP ([HR × SBP] / 100) during BC (106 ± 27 mmHg × beats/min × 10-2 to 91 ± 22 mmHg × beats/min × 10-2, d = 0.6, p < .05) and SP (102 ± 24 mmHg × beats/min × 10-2 to 86 ± 17 mmHg × beats/min × 10-2, d = 0.8, p < .05). Rating of perceived exertion decreased significantly during all exercises (d ranging from 1.8 to 3.1, p < .05): BC (14.3 ± 2.6 to 9.7 ± 1.6), SP (13.9 ± 1.6 to 9.2 ± 1.5), and LP (14.3 ± 1.4 to 10.3 ± 1.6). Peak group FMD responses were 12.8% and 10.3% dilation at pretraining and posttraining, respectively (p > .05). Five of the 15 participants showed modest improvements in their posttraining time to achieve maximum dilation from a mean of 117 s to 81 s, although this change was not statistically significant (p > .05). CONCLUSION Among aerobically trained cardiac patients, a supplemental RT program resulted in decreased hemodynamic and RPE responses to lifting fixed submaximal workloads.
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Brian MS, Matthews EL, Watso JC, Babcock MC, Wenner MM, Rose WC, Stocker SD, Farquhar WB. The influence of acute elevations in plasma osmolality and serum sodium on sympathetic outflow and blood pressure responses to exercise. J Neurophysiol 2017; 119:1257-1265. [PMID: 29357474 DOI: 10.1152/jn.00559.2017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Elevated plasma osmolality (pOsm) has been shown to increase resting sympathetic nerve activity in animals and humans. The present study tested the hypothesis that increases in pOsm and serum sodium (sNa+) concentration would exaggerate muscle sympathetic nerve activity (MSNA) and blood pressure (BP) responses to handgrip (HG) exercise and postexercise ischemia (PEI). BP and MSNA were measured during HG followed by PEI before and after a 23-min hypertonic saline infusion (HSI-3% NaCl). Eighteen participants (age 23 ± 1 yr; BMI 24 ± 1 kg/m2) completed the protocol; pOsm and sNa+ increased from pre- to post-HSI (285 ± 1 to 291 ± 1 mosmol/kg H2O; 138.2 ± 0.3 to 141.3 ± 0.4 mM; P < 0.05 for both). Resting mean BP (90 ± 2 vs. 92 ± 1 mmHg) and MSNA (11 ± 2 vs. 15 ± 2 bursts/min) were increased pre- to post-HSI ( P < 0.05 for both). Mean BP responses to HG (106 ± 2 vs. 111 ± 2 mmHg, P < 0.05) and PEI (102 ± 2 vs. 107 ± 2 mmHg, P < 0.05) were higher post-HSI. Similarly, MSNA during HG (20 ± 2 vs. 29 ± 2 bursts/min, P < 0.05) and PEI (19 ± 2 vs. 24 ± 3 bursts/min, P < 0.05) were greater post-HSI. In addition, the change in MSNA was greater post-HSI during HG (Δ9 ± 2 vs. Δ13 ± 3 bursts/min, P < 0.05). A second set of participants ( n = 13, age 23 ± 1 yr; BMI 24 ± 1 kg/m2) completed a time control (TC) protocol consisting of quiet rest instead of an infusion. The TC condition yielded no change in resting sNa+, pOsm, mean BP, or MSNA (all P > 0.05); responses to HG and PEI were not different pre- to post-quiet rest ( P > 0.05). In summary, acutely increasing pOsm and sNa+ exaggerates BP and MSNA responses during HG exercise and PEI. NEW & NOTEWORTHY Elevated plasma osmolality has been shown to increase resting sympathetic activity and blood pressure. This study provides evidence that acute elevations in plasma osmolality and serum sodium exaggerated muscle sympathetic nerve activity and blood pressure responses during exercise pressor reflex activation in healthy young adults.
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Affiliation(s)
- Michael S Brian
- Department of Kinesiology and Applied Physiology, University of Delaware , Newark, Delaware.,Department of Health and Human Performance, Plymouth State University , Plymouth, New Hampshire
| | - Evan L Matthews
- Department of Kinesiology and Applied Physiology, University of Delaware , Newark, Delaware.,Department of Exercise Science and Physical Education, Montclair State University , Montclair, New Jersey
| | - Joseph C Watso
- Department of Kinesiology and Applied Physiology, University of Delaware , Newark, Delaware
| | - Matthew C Babcock
- Department of Kinesiology and Applied Physiology, University of Delaware , Newark, Delaware
| | - Megan M Wenner
- Department of Kinesiology and Applied Physiology, University of Delaware , Newark, Delaware
| | - William C Rose
- Department of Kinesiology and Applied Physiology, University of Delaware , Newark, Delaware
| | - Sean D Stocker
- Department of Medicine, University of Pittsburgh , Pittsburgh, Pennsylvania
| | - William B Farquhar
- Department of Kinesiology and Applied Physiology, University of Delaware , Newark, Delaware
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Downey RM, Mizuno M, Mitchell JH, Vongpatanasin W, Smith SA. Mineralocorticoid receptor antagonists attenuate exaggerated exercise pressor reflex responses in hypertensive rats. Am J Physiol Heart Circ Physiol 2017; 313:H788-H794. [PMID: 28733447 DOI: 10.1152/ajpheart.00155.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 07/07/2017] [Accepted: 07/17/2017] [Indexed: 01/19/2023]
Abstract
Exaggerated heart rate (HR) and blood pressure responses to exercise in hypertension are mediated, in part, by overactivity of the exercise pressor reflex (EPR). The mechanisms underlying this EPR dysfunction have not been fully elucidated. Previous studies have shown that stimulation of mineralocorticoid receptors (MRs) with exogenous administration of aldosterone in normal, healthy rats reproduces the EPR overactivity characteristic of hypertensive animals. Conversely, the purpose of this study was to examine whether antagonizing MR with spironolactone (SPIR) or eplerenone (EPL) in decerebrated hypertensive rats ameliorates abnormal EPR function. Changes in mean arterial pressure (MAP) and HR induced by EPR or muscle mechanoreflex (a component of EPR) activation were assessed in normotensive Wistar-Kyoto rats and spontaneously hypertensive rats (SHRs) fed normal chow (NC) or a customized diet containing either SPIR or EPL for 3 wk. SHRs treated with SPIR or EPL had significantly attenuated MAP responses to EPR (NC: 45 ± 7 mmHg, SPIR: 26 ± 4 mmHg, and EPL: 24 ± 5 mmHg, P = 0.02) and mechanoreflex (NC: 34 ± 9 mmHg, SPIR: 17 ± 3 mmHg, and EPL: 15 ± 3 mmHg, P = 0.03) activation. SHRs treated with SPIR or EPL also showed significantly attenuated HR responses to EPR (NC: 17 ± 3 beats/min, SPIR: 9 ± 1 beats/min, and EPL: 9 ± 2 beats/min, P = 0.01) and mechanoreflex (NC: 15 ± 3 beats/min, SPIR: 6 ± 1 beats/min, and EPL: 7 ± 1 beats/min, P = 0.01) activation. Wistar-Kyoto rats treated with SPIR did not demonstrate significant differences in MAP or HR responses to EPR or mechanoreflex activation. The data suggest that antagonizing MRs may be an effective strategy for the treatment of EPR overactivity in hypertension.NEW & NOTEWORTHY Exaggerated cardiovascular responses to exercise in hypertensive patients are linked with overactive exercise pressor reflexes (EPRs). Administration of low-dose mineralocorticoid receptor antagonists (spironolactone or eplerenone) effectively ameliorates abnormal EPR function in hypertension. Effective treatment of EPR overactivity may reduce the cardiovascular risks associated with physical activity in hypertension.
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Affiliation(s)
- Ryan M Downey
- Department of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; and
| | - Masaki Mizuno
- Department of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; and
| | - Jere H Mitchell
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; and
| | - Wanpen Vongpatanasin
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; and.,Hypertension Section, Cardiology Division, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Scott A Smith
- Department of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, Texas; .,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; and
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Al-Daydamony MM, El-Tahlawi MA, Shawky A. Can myocardial performance index predict the presence of silent ischemia in asymptomatic type 2 diabetic patients? Echocardiography 2016; 33:1823-1827. [PMID: 27677770 DOI: 10.1111/echo.13359] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Coronary artery disease (CAD) is an important cause of morbidity and mortality in patients with diabetes. Silent myocardial ischemia (SMI) is common in patients with diabetes and is associated with poorer prognosis. Myocardial performance index "Tei index" that reflects both left ventricular (LV) systolic and diastolic function. The aim of our study was to test the value of Tei index in prediction of SMI in asymptomatic patients with type 2 diabetes. PATIENTS AND METHODS Asymptomatic patients with type 2 diabetes were included in our study. We excluded patients with known CAD, previous revascularization, low ejection fraction, or abnormal ECG from the study. All patients had undergone history taking and clinical examination, ECG, echocardiography with measuring of Tei index and Holter monitoring for detecting silent ischemia. RESULTS A total of 200 patients were recruited. We divided our patients into two groups: Group I: 64 patients with SMI, Group II: 136 patients without SMI. There was no significant difference between the two groups regarding clinical and conventional echocardiographic data. Tei index was significantly higher in patients with silent ischemia (P<.00001). Sensitivity, specificity, positive, and negative predictive values of Tei index ≥0.6 in prediction of Holter detected silent ischemia were 85.9%, 90%, 78.6%, and 88.6%, respectively. We found a significant positive correlation between Tei index and number of ischemic episodes (r=.366, P=.0029). CONCLUSION Measuring Tei index is helpful in predicting the presence of silent ischemia in asymptomatic patients with type 2 diabetes.
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Affiliation(s)
| | | | - Ahmad Shawky
- Cardiology Department, Faculty of Medicine, Zagazig University, Zagazig, Egypt
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27
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Victor de Sousa C, Sales MM, Aguiar SDS, Boullosa DA, Rosa TDS, Baldissera V, Simões HG. Double product break point estimates ventilatory threshold in individuals with type 2 diabetes. J Phys Ther Sci 2016; 28:1775-80. [PMID: 27390414 PMCID: PMC4932055 DOI: 10.1589/jpts.28.1775] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 02/28/2016] [Indexed: 11/24/2022] Open
Abstract
[Purpose] To verify the identification of the anaerobic threshold through the double product breakpoint (DPBP) method for individuals with type 2 diabetes. [Subjects and Methods] Nine individuals with T2D (7 females; age=63.2 ± 8.9 y) and 10 non-diabetic (ND) (7 females; age=58.3 ± 7.8 y) performed an incremental exercise test on a cycle ergometer. Heart rate (HR), blood pressure (BP) and expired gas were measured at the end of each stage. The ventilatory threshold (VT) and DPBP were considered as the exercise intensities above which an over proportional increases in VE and DP were observed in relation to increasing workload. [Results] No differences were observed between the workloads, HR and VO2 corresponding to the AT identified respectively by VT and DPBP. For the T2D, strong correlations between VT and DBPB workloads (r=0.853), HR (r=0.714), and VO2 (r=0.863) were found. These relationships were similar to those found for the control group (r=0.923; r=0.881; and r=0.863, respectively). [Conclusion] These results demonstrate that the DPBP enables for the prediction of AT and correlated well the VT in both the T2D and ND participants.
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Affiliation(s)
- Caio Victor de Sousa
- Graduate Program on Physical Education, Universidade Católica de Brasília-UCB, Brazil
| | - Marcelo Magalhães Sales
- Graduate Program on Physical Education, Universidade Católica de Brasília-UCB, Brazil; Health School, UDF -Centro Universitário, Brazil
| | | | | | | | - Vilmar Baldissera
- Faculty of Physical Education, Universidade Federal de São Carlos, Brazil
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Liang N, Mitchell JH, Smith SA, Mizuno M. Exaggerated sympathetic and cardiovascular responses to stimulation of the mesencephalic locomotor region in spontaneously hypertensive rats. Am J Physiol Heart Circ Physiol 2016; 310:H123-31. [PMID: 26545711 PMCID: PMC4796463 DOI: 10.1152/ajpheart.00479.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 11/05/2015] [Indexed: 02/05/2023]
Abstract
The sympathetic and pressor responses to exercise are exaggerated in hypertension. However, the underlying mechanisms causing this abnormality remain to be fully elucidated. Central command, a neural drive originating in higher brain centers, is known to activate cardiovascular and locomotor control circuits concomitantly. As such, it is a viable candidate for the generation of the augmented vascular response to exercise in this disease. We hypothesized that augmentations in central command function contribute to the heightened cardiovascular response to exercise in hypertension. To test this hypothesis, changes in renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP) in response to electrical stimulation of mesencephalic locomotor region (MLR; 20-50 μA in 10-μA steps evoking fictive locomotion), a putative component of the central command pathway, were examined in decerebrate, paralyzed normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). Tibial nerve discharge during MLR stimulation significantly increased in an intensity-dependent manner in both WKY and SHR but was not different between groups. Stimulation of the MLR evoked significantly larger increases in RSNA and MAP with increasing stimulation intensity in both groups. Importantly, the increases in sympathetic and pressor responses to this fictive locomotion were significantly greater in SHR compared with WKY across all stimulation intensities (e.g., at 50 μA, ΔRSNA: WKY 153 ± 31%, SHR 287 ± 42%; ΔMAP: WKY 87 ± 9 mmHg, SHR 139 ± 7 mmHg). These findings provide the first evidence that central command may be a critical contributor to the exaggerated rise in sympathetic activity and blood pressure during exercise in hypertension.
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Affiliation(s)
- Nan Liang
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Jere H Mitchell
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Scott A Smith
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; Department of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, Texas; and
| | - Masaki Mizuno
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; Department of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, Texas; and
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Mizuno M, Mitchell JH, Smith SA. The exercise pressor reflex in hypertension. THE JOURNAL OF PHYSICAL FITNESS AND SPORTS MEDICINE 2016. [DOI: 10.7600/jpfsm.5.339] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Masaki Mizuno
- Department of Health Care Sciences, University of Texas Southwestern Medical Center
- Internal Medicine, University of Texas Southwestern Medical Center
| | - Jere H. Mitchell
- Internal Medicine, University of Texas Southwestern Medical Center
| | - Scott A. Smith
- Department of Health Care Sciences, University of Texas Southwestern Medical Center
- Internal Medicine, University of Texas Southwestern Medical Center
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Holwerda SW, Restaino RM, Manrique C, Lastra G, Fisher JP, Fadel PJ. Augmented pressor and sympathetic responses to skeletal muscle metaboreflex activation in type 2 diabetes patients. Am J Physiol Heart Circ Physiol 2015; 310:H300-9. [PMID: 26566729 DOI: 10.1152/ajpheart.00636.2015] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 11/06/2015] [Indexed: 11/22/2022]
Abstract
Previous studies have reported exaggerated increases in arterial blood pressure during exercise in type 2 diabetes (T2D) patients. However, little is known regarding the underlying neural mechanism(s) involved. We hypothesized that T2D patients would exhibit an augmented muscle metaboreflex activation and this contributes to greater pressor and sympathetic responses during exercise. Mean arterial pressure (MAP), heart rate (HR), and muscle sympathetic nerve activity (MSNA) were measured in 16 patients with T2D (8 normotensive and 8 hypertensive) and 10 healthy controls. Graded isolation of the muscle metaboreflex was achieved by postexercise ischemia (PEI) following static handgrip performed at 30% and 40% maximal voluntary contraction (MVC). A cold pressor test (CPT) was also performed as a generalized sympathoexcitatory stimulus. Increases in MAP and MSNA during 30 and 40% MVC handgrip were augmented in T2D patients compared with controls (P < 0.05), and these differences were maintained during PEI (MAP: 30% MVC PEI: T2D, Δ16 ± 2 mmHg vs. controls, Δ8 ± 1 mmHg; 40% MVC PEI: T2D, Δ26 ± 3 mmHg vs. controls, Δ16 ± 2 mmHg, both P < 0.05). MAP and MSNA responses to handgrip and PEI were not different between normotensive and hypertensive T2D patients (P > 0.05). Interestingly, MSNA responses were also greater in T2D patients compared with controls during the CPT (P < 0.05). Collectively, these findings indicate that muscle metaboreflex activation is augmented in T2D patients and this contributes, in part, to augmented pressor and sympathetic responses to exercise in this patient group. Greater CPT responses suggest that a heightened central sympathetic reactivity may be involved.
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Affiliation(s)
- Seth W Holwerda
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Robert M Restaino
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Camila Manrique
- Department of Medicine, University of Missouri, Columbia, Missouri
| | - Guido Lastra
- Department of Medicine, University of Missouri, Columbia, Missouri
| | - James P Fisher
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Paul J Fadel
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri; Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri; and
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Mizuno M, Iwamoto GA, Vongpatanasin W, Mitchell JH, Smith SA. Dynamic exercise training prevents exercise pressor reflex overactivity in spontaneously hypertensive rats. Am J Physiol Heart Circ Physiol 2015; 309:H762-70. [PMID: 26163445 DOI: 10.1152/ajpheart.00358.2015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 07/04/2015] [Indexed: 11/22/2022]
Abstract
Cardiovascular responses to exercise are exaggerated in hypertension. We previously demonstrated that this heightened cardiovascular response to exercise is mediated by an abnormal skeletal muscle exercise pressor reflex (EPR) with important contributions from its mechanically and chemically sensitive components. Exercise training attenuates exercise pressor reflex function in healthy subjects as well as in heart failure rats. However, whether exercise training has similar physiological benefits in hypertension remains to be elucidated. Thus we tested the hypothesis that the EPR overactivity manifest in hypertension is mitigated by exercise training. Changes in mean arterial pressure (MAP) and renal sympathetic nerve activity (RSNA) in response to muscle contraction, passive muscle stretch, and hindlimb intra-arterial capsaicin administration were examined in untrained normotensive Wistar-Kyoto rats (WKYUT; n = 6), exercise-trained WKY (WKYET; n = 7), untrained spontaneously hypertensive rats (SHRUT; n = 8), and exercise-trained SHR (SHRET; n = 7). Baseline MAP after decerebration was significantly decreased by 3 mo of wheel running in SHRET (104 ± 9 mmHg) compared with SHRUT (125 ± 10 mmHg). As previously reported, the pressor and renal sympathetic responses to muscle contraction, stretch, and capsaicin administration were significantly higher in SHRUT than WKYUT. Exercise training significantly attenuated the enhanced contraction-induced elevations in MAP (SHRUT: 53 ± 11 mmHg; SHRET: 19 ± 3 mmHg) and RSNA (SHRUT: 145 ± 32%; SHRET: 57 ± 11%). Training produced similar attenuating effects in SHR during passive stretch and capsaicin administration. These data demonstrate that the abnormally exaggerated EPR function that develops in hypertensive rats is significantly diminished by exercise training.
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Affiliation(s)
- Masaki Mizuno
- Department of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, Texas; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas;
| | - Gary A Iwamoto
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas; and
| | - Wanpen Vongpatanasin
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; Hypertension Section, Cardiology Division, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Jere H Mitchell
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Scott A Smith
- Department of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, Texas; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
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Vianna LC, Fadel PJ, Secher NH, Fisher JP. A cholinergic contribution to the circulatory responses evoked at the onset of handgrip exercise in humans. Am J Physiol Regul Integr Comp Physiol 2015; 308:R597-604. [PMID: 25589014 DOI: 10.1152/ajpregu.00236.2014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 01/07/2015] [Indexed: 02/05/2023]
Abstract
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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Affiliation(s)
- Lauro C Vianna
- Faculty of Physical Education, University of Brasília, Brasília, Brazil
| | - Paul J Fadel
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Niels H Secher
- Department of Anaesthesia, The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Denmark; and
| | - James P Fisher
- School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, United Kingdom
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Smith SA, Leal AK, Murphy MN, Downey RM, Mizuno M. Muscle mechanoreflex overactivity in hypertension: a role for centrally-derived nitric oxide. Auton Neurosci 2015; 188:58-63. [PMID: 25630887 DOI: 10.1016/j.autneu.2014.12.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 12/10/2014] [Accepted: 12/24/2014] [Indexed: 02/07/2023]
Abstract
The cardiovascular response to exercise is abnormally large in hypertension. Over the past decade, it has become clear that the exercise pressor reflex (a peripheral feed-back mechanism originating in skeletal muscle) contributes significantly to the generation of this hyper-responsiveness. Further, it has been determined that overactivity of the mechanically (muscle mechanoreflex) and chemically (muscle metaboreflex) sensitive components of the exercise pressor reflex underpin its dysfunction. Given the recent attention in the literature, this review focuses upon the aberrant function of the muscle mechanoreflex in this disease. Evidence supporting a role for the mechanoreflex in the pathogenesis of the exaggerated cardiovascular response to physical activity is highlighted. The peripheral and central mechanisms that may be responsible for mechanoreflex overactivity in hypertension are likewise discussed. Particular attention is given to emerging evidence implicating a role for centrally-derived nitric oxide in this process.
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Affiliation(s)
- Scott A Smith
- Department of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, TX, United States; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, United States.
| | - Anna K Leal
- Department of Kinesiology, Berry College, Mount Berry, GA, United States
| | - Megan N Murphy
- Department of Applied Physiology and Wellness, Southern Methodist University, Dallas, TX, United States
| | - Ryan M Downey
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Masaki Mizuno
- Department of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, TX, United States; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, United States
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Exaggerated increases in blood pressure during isometric muscle contraction in hypertension: role for purinergic receptors. Auton Neurosci 2014; 188:51-7. [PMID: 25577671 DOI: 10.1016/j.autneu.2014.12.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 10/15/2014] [Accepted: 12/17/2014] [Indexed: 01/27/2023]
Abstract
Physical activity is a cornerstone therapy for the primary prevention and treatment of hypertension, which is becoming increasingly prevalent in modern societies. During exercise, heart rate and blood pressure (BP) increase in order to acutely meet the metabolic demands of the working skeletal muscle. In hypertensive adults, isometric exercise-induced increases in BP are excessive, potentially increasing the risk of an acute cardiovascular event during or after physical activity. Recently, the skeletal muscle metaboreflex has emerged as a significant contributor to the development of aberrant cardiovascular control during isometric exercise in this clinical population. Our laboratory has conducted a series of studies characterizing the skeletal muscle metaboreflex in hypertensive humans. We and others have demonstrated that hypertension is characterized by greater increases in muscle sympathetic nerve activity and BP during selective activation of the metaboreflex during post-exercise muscle ischemia compared to the increases noted in healthy age-matched normotensive adults, suggesting that the skeletal muscle metaboreflex is exaggerated in human hypertension. The focus of this review is the skeletal muscle metaboreflex (i.e., the metabolic component of the exercise pressor reflex) in hypertension, with particular emphasis on the potential role of purinergic receptors in mediating the exaggerated responses to muscle metaboreflex activation.
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Rapid onset pressor and sympathetic responses to static handgrip in older hypertensive adults. J Hum Hypertens 2014; 29:402-8. [PMID: 25471615 DOI: 10.1038/jhh.2014.106] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 08/14/2014] [Accepted: 08/22/2014] [Indexed: 11/08/2022]
Abstract
Exaggerated pressor and muscle sympathetic nerve activity (MSNA) responses have been reported during static handgrip in hypertensive (HTN) adults. Recent work suggests that such responses may occur much more rapidly in HTN patients; however, this has not been extensively studied. Thus, we examined the blood pressure (BP) and MSNA responses at the immediate onset of muscle contraction and tested the hypothesis that older HTN adults would exhibit rapid onset pressor and sympathetic responses compared with normotensive (NTN) adults. Heart rate (HR), BP (Finometer) and MSNA (peroneal microneurography) were retrospectively analyzed in 15 HTN (62 ± 1 years; resting BP 153 ± 3/91 ± 5 mm Hg) and 23 age-matched NTN (60 ± 1 years; resting BP 112 ± 1/67 ± 2 mm Hg) subjects during the first 30 s of static handgrip at 30 and 40% of maximal voluntary contraction (MVC). HTN adults demonstrated exaggerated increases in mean BP during the first 10 s of both 30% (NTN: Δ1 ± 1 vs HTN: Δ7 ± 2 mm Hg; P < 0.05) and 40% (NTN: Δ2 ± 1 vs HTN: Δ8 ± 2 mm Hg; P < 0.05) intensity handgrip. Likewise, HTN adults exhibited atypical increases in MSNA within 10 s. Increases in HR were also greater in HTN adults at 10 s of 30% MVC handgrip, although not at 40% MVC. There were no group differences in 10 s pressor or sympathetic responses to a cold pressor test, suggesting no differences in generalized sympathetic responsiveness. Thus, static handgrip evokes rapid onset pressor and sympathetic responses in older HTN adults. These findings suggest that older HTN adults likely have greater cardiovascular risk even during short duration activities of daily living that contain an isometric component.
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Billinger SA, Arena R, Bernhardt J, Eng JJ, Franklin BA, Johnson CM, MacKay-Lyons M, Macko RF, Mead GE, Roth EJ, Shaughnessy M, Tang A. Physical Activity and Exercise Recommendations for Stroke Survivors. Stroke 2014; 45:2532-53. [PMID: 24846875 DOI: 10.1161/str.0000000000000022] [Citation(s) in RCA: 841] [Impact Index Per Article: 84.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Mizuno M, Iwamoto GA, Vongpatanasin W, Mitchell JH, Smith SA. Exercise training improves functional sympatholysis in spontaneously hypertensive rats through a nitric oxide-dependent mechanism. Am J Physiol Heart Circ Physiol 2014; 307:H242-51. [PMID: 24816260 DOI: 10.1152/ajpheart.00103.2014] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Functional sympatholysis is impaired in hypertensive animals and patients. Exercise training (ET) improves functional sympatholysis through a nitric oxide (NO)-dependent mechanism in normotensive rats. However, whether ET has similar physiological benefits in hypertension remains to be elucidated. Thus we tested the hypothesis that the impairment in functional sympatholysis in hypertension is reversed by ET through a NO-dependent mechanism. In untrained normotensive Wistar-Kyoto rats (WKYUT; n = 13), untrained spontaneously hypertensive rats (SHRUT; n = 13), and exercise-trained SHR (SHRET; n = 6), changes in femoral vascular conductance (FVC) were examined during lumbar sympathetic nerve stimulation (1, 2.5, and 5 Hz) at rest and during muscle contraction. The magnitude of functional sympatholysis (Δ%FVC = Δ%FVC muscle contraction - Δ%FVC rest) in SHRUT was significantly lower than WKYUT (1 Hz: -2 ± 4 vs. 13 ± 3%; 2.5 Hz: 9 ± 3 vs. 21 ± 3%; and 5 Hz: 12 ± 3 vs. 26 ± 3%, respectively; P < 0.05). Three months of voluntary wheel running significantly increased maximal oxygen uptake in SHRET compared with nontrained SHRUT (78 ± 6 vs. 62 ± 4 ml·kg(-1)·min(-1), respectively; P < 0.05) and restored the magnitude of functional sympatholysis in SHRET (1 Hz: 9 ± 2%; 2.5 Hz: 20 ± 4%; and 5 Hz: 34 ± 5%). Blockade of NO synthase (NOS) by N(G)-nitro-l-arginine methyl ester attenuated functional sympatholysis in WKYUT but not SHRUT. Furthermore, NOS inhibition significantly diminished the improvements in functional sympatholysis in SHRET. These data demonstrate that impairments in functional sympatholysis are normalized via a NO mechanism by voluntary wheel running in hypertensive rats.
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Affiliation(s)
- Masaki Mizuno
- Department of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Gary A Iwamoto
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Wanpen Vongpatanasin
- Department of Hypertension Section University of Texas Southwestern Medical Center, Dallas, Texas; and Division of Cardiology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Jere H Mitchell
- Division of Cardiology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Scott A Smith
- Department of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, Texas; Division of Cardiology, University of Texas Southwestern Medical Center, Dallas, Texas
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Greaney JL, Matthews EL, Boggs ME, Edwards DG, Duncan RL, Farquhar WB. Exaggerated exercise pressor reflex in adults with moderately elevated systolic blood pressure: role of purinergic receptors. Am J Physiol Heart Circ Physiol 2014; 306:H132-41. [DOI: 10.1152/ajpheart.00575.2013] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The neurocirculatory responses to exercise are exaggerated in hypertension, increasing cardiovascular risk, yet the mechanisms remain incompletely understood. The aim of this study was to examine the in vitro effectiveness of pyridoxal-5-phosphate as a purinergic (P2) receptor antagonist in isolated murine dorsal root ganglia (DRG) neurons and the in vivo contribution of P2 receptors to the neurocirculatory responses to exercise in older adults with moderately elevated systolic blood pressure (BP). In vitro, pyridoxal-5-phosphate attenuated the ATP-induced increases in [Ca2+]i (73 ± 15 vs. 11 ± 3 nM; P < 0.05). In vivo, muscle sympathetic nerve activity (MSNA; peroneal microneurography) and arterial BP (Finometer) were assessed during exercise pressor reflex activation (static handgrip followed by postexercise ischemia; PEI) during a control trial (normal saline) and localized P2 receptor blockade (pyridoxal-5-phosphate). Compared with normotensive adults (63 ± 2 yr, 117 ± 2/70 ± 2 mmHg), adults with moderately elevated systolic BP (65 ± 1 yr, 138 ± 5/79 ± 3 mmHg) demonstrated greater increases in MSNA and BP during handgrip and PEI. Compared with the control trial, local antagonism of P2 receptors during PEI partially attenuated MSNA (39 ± 4 vs. 34 ± 5 bursts/min; P < 0.05) in adults with moderately elevated systolic BP. In conclusion, these data demonstrate pyridoxal-5-phosphate is an effective P2 receptor antagonist in isolated DRG neurons, which are of particular relevance to the exercise pressor reflex. Furthermore, these findings indicate that exercise pressor reflex function is exaggerated in older adults with moderately elevated systolic BP and further suggest a modest role of purinergic receptors in evoking the abnormally large reflex-mediated increases in sympathetic activity during exercise in this clinical population.
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Affiliation(s)
- Jody L. Greaney
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, Delaware; and
- Department of Biological Sciences, University of Delaware, Newark, Delaware
| | - Evan L. Matthews
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, Delaware; and
| | - Mary E. Boggs
- Department of Biological Sciences, University of Delaware, Newark, Delaware
| | - David G. Edwards
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, Delaware; and
- Department of Biological Sciences, University of Delaware, Newark, Delaware
| | - Randall L. Duncan
- Department of Biological Sciences, University of Delaware, Newark, Delaware
| | - William B. Farquhar
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, Delaware; and
- Department of Biological Sciences, University of Delaware, Newark, Delaware
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Mizuno M, Lozano G, Siddique K, Baum M, Smith SA. Enalapril attenuates the exaggerated sympathetic response to physical stress in prenatally programmed hypertensive rats. Hypertension 2013; 63:324-9. [PMID: 24191284 DOI: 10.1161/hypertensionaha.113.02330] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Adulthood hypertension can be prenatally programmed by maternal dietary protein deprivation. We have shown that the sympathetically mediated pressor response to physical stress is exaggerated in prenatally programmed hypertensive (PPH) rats. The mechanisms underlying this abnormal responsiveness remain undetermined. The renin-angiotensin system is known to affect sympathetic nerve activity. Therefore, the purpose of this study was to determine whether inhibition of the renin-angiotensin system attenuates the enhanced sympathetic and pressor responses to physical stress in PPH rats. Changes in renal sympathetic nerve activity and blood pressure in response to hindlimb contraction, hindlimb stretch, and hindlimb intra-arterial capsaicin administration were assessed in control and PPH rats treated (from age 3 weeks) with either vehicle or the angiotensin-converting enzyme inhibitor enalapril. Conscious resting systolic arterial pressure was significantly greater in PPH rats (142±5 mm Hg) than in control (128±2 mm Hg) after vehicle treatment (P<0.05). Resting systolic pressure was reduced by enalapril treatment in PPH rats (125±2 mm Hg) but had no effect in control (128±2 mm Hg). The pressor and renal sympathetic responses to muscle contraction and stretch were significantly higher in decerebrate PPH rats than in decerebrate control in vehicle-treated groups. Responses to capsaicin were variable. Enalapril significantly attenuated the enhanced contraction-induced elevations in mean pressure (vehicle, 45±6 mm Hg; enalapril, 21±3 mm Hg) and renal sympathetic activity (vehicle, 175±22%; enalapril, 89±23%) in PPH rats. Its effects were similar on responses to stretch in PPH rats but were equivocal during capsaicin administration. The results suggest that the renin-angiotensin system contributes to the enhancement of the renal sympathetic and pressor responses to physical stress in PPH rats.
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Affiliation(s)
- Masaki Mizuno
- University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-9174. ,
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Boyne P, Dunning K, Carl D, Gerson M, Khoury J, Kissela B. High-intensity interval training in stroke rehabilitation. Top Stroke Rehabil 2013; 20:317-30. [PMID: 23893831 DOI: 10.1310/tsr2004-317] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
After stroke, people with weakness enter a vicious cycle of limited activity and deconditioning that limits functional recovery and exacerbates cardiovascular risk factors. Conventional aerobic exercise improves aerobic capacity, function, and overall cardiometabolic health after stroke. Recently, a new exercise strategy has shown greater effectiveness than conventional aerobic exercise for improving aerobic capacity and other outcomes among healthy adults and people with heart disease. This strategy, called high-intensity interval training (HIT), uses bursts of concentrated effort alternated with recovery periods to maximize exercise intensity. Three poststroke HIT studies have shown preliminary effectiveness for improving functional recovery. However, these studies were varied in approach and the safety of poststroke HIT has received little attention. The objectives of this narrative review are to (1) propose a framework for categorizing HIT protocols; (2) summarize the safety and effectiveness evidence of HIT among healthy adults and people with heart disease and stroke; (3) discuss theoretical mechanisms, protocol selection, and safety considerations for poststroke HIT; and (4) provide directions for future research.
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Affiliation(s)
- Pierce Boyne
- Department of Rehabilitation Sciences, College of Allied Health Sciences, University of Cincinnati, Cincinnati, OH, USA
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Williams RP, Manou-Stathopoulou V, Redwood SR, Marber MS. ‘Warm-up Angina’: harnessing the benefits of exercise and myocardial ischaemia. Heart 2013; 100:106-14. [DOI: 10.1136/heartjnl-2013-304187] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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Leal AK, Mitchell JH, Smith SA. Treatment of muscle mechanoreflex dysfunction in hypertension: effects of L-arginine dialysis in the nucleus tractus solitarii. Exp Physiol 2013; 98:1337-48. [PMID: 23771911 DOI: 10.1113/expphysiol.2012.071563] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Does increasing NO production within the nucleus tractus solitarii (NTS) affect mechanoreflex function in normotensive and hypertensive rats?What is the main finding and its importance? Dialysis of 1 μm l-arginine, an NO precursor, within the NTS significantly attenuated the pressor response to muscle stretch in normotensive and hypertensive rats. In contrast, 10 μm l-arginine had no effect in normotensive animals, while increasing and decreasing the pressor and tachycardic responses to stretch, respectively, in hypertensive rats. This suggests that increasing NO within the NTS using lower doses of l-arginine can partly normalize mechanoreflex overactivity in hypertensive rats, whereas the effects of larger doses are equivocal. The blood pressure response to exercise is exaggerated in hypertension. Recent evidence suggests that an overactive skeletal muscle mechanoreflex contributes significantly to this augmented circulatory responsiveness. Sensory information from the mechanoreflex is processed within the nucleus tractus solitarii (NTS) of the medulla oblongata. Normally, endogenously produced nitric oxide within the NTS attenuates the increase in mean arterial pressure (MAP) induced by mechanoreflex stimulation. Thus, it has been suggested that decreases in NO production in the NTS underlie the generation of mechanoreflex dysfunction in hypertension. Supporting this postulate, it has been shown that blocking NO production within the NTS of normotensive rats reproduces the exaggerated pressor response elicited by mechanoreflex activation in hypertensive animals. What is not known is whether increasing NO production within the NTS of hypertensive rats mitigates mechanoreflex overactivity. In this study, the mechanoreflex was selectively activated by passively stretching hindlimb muscle before and after the dialysis of 1 and 10 μm l-arginine (an NO precursor) within the NTS of decerebrate normotensive Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHRs). Stretch induced larger elevations in MAP in SHRs compared with WKY rats. In both groups, dialysis of 1 μm l-arginine significantly attenuated the pressor response to stretch. However, at the 10 μm dose, l-arginine had no effect on the MAP response to stretch in WKY rats, while it enhanced the response in SHRs. The data demonstrate that increasing NO availability within the NTS using lower doses of l-arginine partly normalizes mechanoreflex dysfunction in hypertension, whereas higher doses do not. The findings could prove valuable in the development of treatment options for mechanoreflex overactivity in this disease.
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Affiliation(s)
- Anna K Leal
- Department of Bioengineering, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
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Murphy MN, Mizuno M, Downey RM, Squiers JJ, Squiers KE, Smith SA. Neuronal nitric oxide synthase expression is lower in areas of the nucleus tractus solitarius excited by skeletal muscle reflexes in hypertensive rats. Am J Physiol Heart Circ Physiol 2013; 304:H1547-57. [PMID: 23564306 PMCID: PMC3680727 DOI: 10.1152/ajpheart.00235.2012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Accepted: 03/08/2013] [Indexed: 11/22/2022]
Abstract
The functions of the skeletal muscle exercise pressor reflex (EPR) and its mechanically sensitive component are augmented in hypertension producing exaggerated increases in blood pressure during exercise. Afferent information from the EPR is processed in the nucleus tractus solitarius (NTS). Within the NT, nitric oxide (NO), produced via L-arginine oxidation by neuronal nitric oxide synthase (nNOS), buffers the pressor response to EPR activation. Therefore, EPR overactivity may manifest as a decrease in NO production due to reductions in nNOS. We hypothesized that nNOS protein expression is lower in the NTS of spontaneously hypertensive (SHR) compared with normotensive Wistar-Kyoto (WKY) rats. Further, we examined whether nNOS is expressed with FOS, a marker of neuronal excitation induced by EPR activation. The EPR and mechanoreflex were intermittently activated for 1 h via hindlimb static contraction or stretch, respectively. These maneuvers produced significantly greater pressor responses in SHR during the first 25 min of stimulation. Within the NTS, nNOS expression was lower from -14.9 to -13.4 bregma in SHR compared with WKY. For example, at -14.5 bregma the number of NTS nNOS-positive cells in SHR (13 ± 1) was significantly less than WKY (23 ± 2). However, the number of FOS-positive cells after muscle contraction in this area was not different (WKY = 82 ± 18; SHR = 75 ± 8). In both groups, FOS-expressing neurons were located within the same areas of the NTS as neurons containing nNOS. These findings demonstrate that nNOS protein expression is lower within NTS areas excited by skeletal muscle reflexes in hypertensive rats.
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Affiliation(s)
- Megan N Murphy
- Department of Physical Therapy, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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Franklin BA, Billecke S. Putting the benefits and risks of aerobic exercise in perspective. Curr Sports Med Rep 2012; 11:201-8. [PMID: 22777331 DOI: 10.1249/jsr.0b013e31825dabd4] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Although considerable epidemiologic and clinical evidence suggests that structured exercise, increased lifestyle activity, or both are cardioprotective, the absolute and relative risk of cardiovascular and musculoskeletal complications appear to increase transiently during vigorous physical activity. The estimated relative risk of exercise-related cardiac events ranges from 2.1 to 56 and is highest among habitually sedentary individuals with underlying cardiovascular disease who were performing unaccustomed vigorous physical exertion. Moreover, an estimated 7 million Americans receive medical attention for sports and recreation-related injuries each year. These risks, and their modulators, should be considered when endorsing strenuous leisure time or exercise interventions. If the current mantra "exercise is medicine" is embraced, underdosing and overdosing are possible. Thus, exercise may have a typical dose-response curve with a plateau in benefit or even adverse effects, in some individuals, at more extreme levels.
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Affiliation(s)
- Barry A Franklin
- Preventive Cardiology and Rehabilitation, Beaumont Health System, Royal Oak, MI 48073, USA.
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Leal AK, Murphy MN, Iwamoto GA, Mitchell JH, Smith SA. A role for nitric oxide within the nucleus tractus solitarii in the development of muscle mechanoreflex dysfunction in hypertension. Exp Physiol 2012; 97:1292-304. [PMID: 22581746 PMCID: PMC3480555 DOI: 10.1113/expphysiol.2012.065433] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Evidence suggests that the muscle mechanoreflex, a circulatory reflex that raises blood pressure and heart rate (HR) upon activation of mechanically sensitive afferent fibres in skeletal muscle, is overactive in hypertension. However, the mechanisms underlying this abnormal reflex function have yet to be identified. Sensory input from the mechanoreflex is processed within the nucleus tractus solitarii (NTS) in the medulla oblongata. Within the NTS, the enzymatic activity of nitric oxide synthase produces nitric oxide (NO). This centrally derived NO has been shown to modulate muscle reflex activity and serves as a viable candidate for mediating the mechanoreflex dysfunction that develops in hypertension. We hypothesized that mechanoreflex dysfunction in hypertension is mediated by abnormal alterations in NO production in the NTS. Mechanically sensitive afferent fibres were stimulated by passively stretching hindlimb muscle before and after blocking the endogenous production of NO within the NTS via microdialysis of the NO synthase inhibitor L-NAME (1 and 5 mM) in normotensive Wistar-Kyoto rats and spontaneously hypertensive rats (SHRs). Changes in HR and mean arterial pressure in response to stretch were significantly larger in SHRs compared with Wistar-Kyoto rats prior to L-NAME dialysis. Attenuating NO production via L-NAME in normotensive rats recapitulated the exaggerated cardiovascular response to stretch observed in SHRs. Dialysing L-NAME in SHRs further accentuated the increases in HR and mean arterial pressure elicited by stretch. These findings support the contention that reductions in NO production within the NTS contribute to the generation of abnormal cardiovascular control by the skeletal muscle mechanoreflex in hypertension.
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Affiliation(s)
- Anna K. Leal
- Department of Bioengineering, University of Texas Southwestern Medical Center, Dallas, Texas, USA 75390-9174
| | - Megan N. Murphy
- Department of Physical Therapy, University of Texas Southwestern Medical Center, Dallas, Texas, USA 75390-9174
| | - Gary A. Iwamoto
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas, USA 75390-9174
| | - Jere H. Mitchell
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA 75390-9174
| | - Scott A. Smith
- Department of Bioengineering, University of Texas Southwestern Medical Center, Dallas, Texas, USA 75390-9174
- Department of Physical Therapy, University of Texas Southwestern Medical Center, Dallas, Texas, USA 75390-9174
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA 75390-9174
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Mizuno M, Siddique K, Baum M, Smith SA. Prenatal programming of hypertension induces sympathetic overactivity in response to physical stress. Hypertension 2012; 61:180-6. [PMID: 23150514 DOI: 10.1161/hypertensionaha.112.199356] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Small-for-gestational-age infants are known to develop hypertension in adulthood. This prenatal programming of hypertension (PPH) can result from several insults including maternal dietary protein deprivation, uteroplacental insufficiency, and prenatal administration of glucocorticoids. The mechanisms underlying the development of hypertension remain unclear although the sympathetic nervous system has been indirectly implicated. This study was designed to directly measure renal sympathetic nerve activity both at rest and during physical stress in an animal model of PPH. The adult male offspring of rats fed either a 6% (PPH) or 20% protein diet (control) were investigated. Conscious systolic blood pressure measured by tail cuff was significantly higher in PPH compared with control (140 ± 3 versus 128 ± 3 mm Hg; P<0.05). Baseline mean arterial pressure, heart rate, and renal sympathetic activity were not different between groups during isoflurane anesthesia or after decerebration. Physical stress was induced in decerebrate animals by activating the exercise pressor reflex during static muscle contraction. Stimulation of the exercise pressor reflex evoked significantly larger changes from baseline in mean arterial pressure (40 ± 7 versus 20 ± 4 mm Hg; P<0.05), heart rate (19 ± 3 versus 5 ± 1 bpm; P<0.05), and renal sympathetic activity (198 ± 29% versus 68 ± 14%; P<0.05) in PPH as compared with control. The data demonstrate that the sympathetic response to physical stress is markedly exaggerated in PPH and may play a significant role in the development of hypertension in adults born small for gestational age.
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Affiliation(s)
- Masaki Mizuno
- Departments of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, TX, USA
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Guiraud T, Nigam A, Gremeaux V, Meyer P, Juneau M, Bosquet L. High-intensity interval training in cardiac rehabilitation. Sports Med 2012; 42:587-605. [PMID: 22694349 DOI: 10.2165/11631910-000000000-00000] [Citation(s) in RCA: 179] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
High-intensity interval training (HIIT) is frequently used in sports training. The effects on cardiorespiratory and muscle systems have led scientists to consider its application in the field of cardiovascular diseases. The objective of this review is to report the effects and interest of HIIT in patients with coronary artery disease (CAD) and heart failure (HF), as well as in persons with high cardiovascular risk. A non-systematic review of the literature in the MEDLINE database using keywords 'exercise', 'high-intensity interval training', 'interval training', 'coronary artery disease', 'coronary heart disease', 'chronic heart failure' and 'metabolic syndrome' was performed. We selected articles concerning basic science research, physiological research, and randomized or non-randomized interventional clinical trials published in English. To summarize, HIIT appears safe and better tolerated by patients than moderate-intensity continuous exercise (MICE). HIIT gives rise to many short- and long-term central and peripheral adaptations in these populations. In stable and selected patients, it induces substantial clinical improvements, superior to those achieved by MICE, including beneficial effects on several important prognostic factors (peak oxygen uptake, ventricular function, endothelial function), as well as improving quality of life. HIIT appears to be a safe and effective alternative for the rehabilitation of patients with CAD and HF. It may also assist in improving adherence to exercise training. Larger randomized interventional studies are now necessary to improve the indications for this therapy in different populations.
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Affiliation(s)
- Thibaut Guiraud
- Montreal Heart Institute, Cardiovascular Prevention Centre-Centre PIC, Universit de Montral, Montral, Qubec, Canada.
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Choi HM, Stebbins CL, Nho H, Kim KA, Kim C, Kim JK. Skeletal muscle metaboreflex is enhanced in postmenopausal women. Eur J Appl Physiol 2011; 112:2671-8. [DOI: 10.1007/s00421-011-2245-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 11/09/2011] [Indexed: 11/24/2022]
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