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Hamaoka T, Sinoway LI, Cui J. The role of peripheral venous distension reflex in regulating hemodynamics: mini review. Auton Neurosci 2024; 256:103217. [PMID: 39270515 DOI: 10.1016/j.autneu.2024.103217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 07/31/2024] [Accepted: 09/03/2024] [Indexed: 09/15/2024]
Abstract
Significant volume is pooled in veins in humans and the amount is dramatically altered by various physiological stresses and diseases. Several animal and human studies demonstrated that limb venous distension evoked significant increases in blood pressure and sympathetic nerve activity (venous distension reflex, VDR). VDR has attracted much attention because of its potential to explain the still unknown mechanism of autonomic dysfunction in several diseases, which would lead to a new treatment approach. This mini review discusses accumulated evidence of VDR at this point and what should be investigated in the future to apply the current understanding of VDR in clinical practice.
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Affiliation(s)
- Takuto Hamaoka
- Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA 17033, United States of America
| | - Lawrence I Sinoway
- Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA 17033, United States of America
| | - Jian Cui
- Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA 17033, United States of America.
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2
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Giersch GEW, Charkoudian N. Regulation of body temperature and blood pressure in women: Mechanisms and implications for heat illness risk. Exp Physiol 2024. [PMID: 38607298 DOI: 10.1113/ep091455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Accepted: 03/21/2024] [Indexed: 04/13/2024]
Abstract
Increasing global temperatures due to ongoing climate change phenomena have resulted in increased risk of exertional heat illness in otherwise healthy, young individuals who work or play in the heat. With increasing participation of women in athletic, military and industrial activities that involve exertion in the heat, there is a growing need to study female physiology in this context. Mechanisms controlling blood pressure and body temperature have substantial overlap in humans, largely due to autonomic mechanisms which contribute to both. Similarly, illnesses that result from excessive heat exposure can often be traced back to imbalances in one or more of these autonomic mechanisms. In recent years, there has been increased recognition of the importance of sex as a biological variable for basic and applied research in these areas. The goal of this paper is to present an update on the integrative physiology and pathophysiology of responses to heat stress in women (thermoregulation and blood pressure regulation). In this context, it is often the case that differences between sexes are presented as 'advantages' and 'disadvantages' of one sex over the other. In our opinion, this is an over-simplification of the physiology which ignores the nuances and complexities of the integrative physiology of responses to heat exposure and exercise, and their relevance for practical outcomes.
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Affiliation(s)
| | - Nisha Charkoudian
- US Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
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Silpe J, Koleilat I, Yu J, Kim YH, Taubenfeld E, Talathi S, Coluccio M, Wang K, Woo K, Etkin Y. Sex disparities in hemodialysis access outcomes: A systematic review. Semin Vasc Surg 2023; 36:560-570. [PMID: 38030330 DOI: 10.1053/j.semvascsurg.2023.10.002] [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: 07/26/2023] [Revised: 10/01/2023] [Accepted: 10/02/2023] [Indexed: 12/01/2023]
Abstract
The goal of this systematic review was to collate and summarize the current literature on hemodialysis access outcomes in females, identify differences between females and men, and provide a foundation for future research. A systematic review of the English-language literature was conducted by searching PubMed and Google Scholar for the following terms: "sex," "hemodialysis access," "arteriovenous fistula," "arteriovenous graft," and "dialysis catheter." Reference lists from the resulting articles were also evaluated to ensure that any and all relevant primary sources were identified. Studies were then screened by two independent reviewers for inclusion. Of 967 total studies, 53 ultimately met inclusion criteria. Females have lower maturation rates; have decreased rates of primary, primary-assisted, and secondary patency; require more procedures per capita to achieve maturation and to maintain fistula patency; are more likely to receive dialysis via an arteriovenous graft or central venous catheter; and require a longer time and potentially more assistive invasive interventions to achieve a mature fistula. Our findings emphasize the urgent need for further research to evaluate and address the causes of these disparities. Discussion with patients undergoing hemodialysis should include these findings to improve patient education, expectations, satisfaction, and outcomes.
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Affiliation(s)
- Jeffrey Silpe
- Division of Vascular and Endovascular Surgery, Zucker School of Medicine at Hofstra/Northwell, 1999 Marcus Avenue, Suite 106b Lake Success, NY.
| | - Issam Koleilat
- Department of Surgery, RWJ Barnabas Health Community Medical Center, Tom's River, NJ
| | - Justin Yu
- Division of Vascular and Endovascular Surgery, Zucker School of Medicine at Hofstra/Northwell, 1999 Marcus Avenue, Suite 106b Lake Success, NY
| | - Young Hun Kim
- Division of Vascular and Endovascular Surgery, Zucker School of Medicine at Hofstra/Northwell, 1999 Marcus Avenue, Suite 106b Lake Success, NY
| | - Ella Taubenfeld
- Division of Vascular and Endovascular Surgery, Zucker School of Medicine at Hofstra/Northwell, 1999 Marcus Avenue, Suite 106b Lake Success, NY
| | - Sonia Talathi
- Division of Vascular and Cardiothoracic Surgery, Montefiore Medical Center/Albert Einstein College of Medicine, Bronx, NY
| | - Maria Coluccio
- Division of Vascular and Cardiothoracic Surgery, Montefiore Medical Center/Albert Einstein College of Medicine, Bronx, NY
| | - Karissa Wang
- Division of Vascular Surgery, Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Karen Woo
- Division of Vascular Surgery, Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Yana Etkin
- Division of Vascular and Endovascular Surgery, Zucker School of Medicine at Hofstra/Northwell, 1999 Marcus Avenue, Suite 106b Lake Success, NY
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Hamaoka T, Leuenberger UA, Kronfli A, Gao Z, Blaha C, Luck JC, Dalton P, Sinoway LI, Cui J. Effect of Cyclooxygenase Inhibition on Peripheral Venous Distension Reflex in Healthy Humans. Hypertension 2023; 80:1102-1109. [PMID: 36942572 PMCID: PMC10133193 DOI: 10.1161/hypertensionaha.122.20506] [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: 10/19/2022] [Accepted: 03/07/2023] [Indexed: 03/23/2023]
Abstract
BACKGROUND Peripheral venous distension evokes a pressor reflex (venous distension reflex). Afferent group III and IV nerves innervating veins are suggested as the afferent arm of the venous distension reflex. Prostaglandins stimulate/sensitize group III/IV nerves. We hypothesized that inhibition of prostaglandin synthesis by local cyclooxygenase blockade would attenuate the muscle sympathetic nerve activity (MSNA) and blood pressure responses to venous distension. METHODS Nineteen healthy volunteers (age, 27±5 years) participated in the study with 2 visits. To induce venous distension, a volume of solution (saline alone or 9 mg ketorolac tromethamine in saline) was infused into the vein in the antecubital fossa of an arterially occluded forearm. During the procedure, beat-by-beat heart rate, blood pressure and MSNA were recorded simultaneously. The vein size was measured with ultrasound. RESULTS In both visits, the venous distension procedure significantly increased blood pressure, heart rate, and MSNA (all, P<0.05). The increase in mean arterial pressure and MSNA in the ketorolac visit was significantly lower than in the control visit (∆ mean arterial pressure, 7.0±6.2 versus 13.8±7.7 mm Hg; ∆MSNA, 6.0±7.1 versus 14.8±7.7 bursts/min; both, P<0.05). The increase in vein size induced by the infusion was not different between visits. CONCLUSIONS The presented data show that cyclooxygenase blockade attenuates the responses in MSNA and blood pressure to peripheral venous distension reflex. The results suggest that cyclooxygenase products play a key role in evoking afferent activation responsible for the venous distension reflex.
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Affiliation(s)
- Takuto Hamaoka
- Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Urs A. Leuenberger
- Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Anthony Kronfli
- Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Zhaohui Gao
- Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Cheryl Blaha
- Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Jonathan Carter Luck
- Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Paul Dalton
- Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Lawrence I. Sinoway
- Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Jian Cui
- Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA 17033
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Sex Differences in VO 2max and the Impact on Endurance-Exercise Performance. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19094946. [PMID: 35564339 PMCID: PMC9105160 DOI: 10.3390/ijerph19094946] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 04/15/2022] [Indexed: 02/04/2023]
Abstract
It was not until 1984 that women were permitted to compete in the Olympic marathon. Today, more women than men participate in road racing in all distances except the marathon where participation is near equal. From the period of 1985 to 2004, the women’s marathon record improved at a rate three times greater than men’s. This has led many to question whether women are capable of surpassing men despite the fact that there remains a 10–12% performance gap in all distance events. The progressive developments in sports performance research and training, beginning with A.V. Hill’s establishment of the concept of VO2max, have allowed endurance athletes to continue performance feats previously thought to be impossible. However, even today women are significantly underrepresented in sports performance research. By focusing more research on the female physiology and sex differences between men and women, we can better define how women differ from men in adapting to training and potentially use this information to improve endurance-exercise performance in women. The male advantage in endurance-exercise performance has commonly been attributed to their higher VO2max, even when expressed as mL/kg/min. It is widely known that oxygen delivery is the primary limiting factor in elite athletes when it comes to improving VO2max, but little research has explored the sex differences in oxygen delivery. Thus, the purpose of this review is to highlight what is known about the sex differences in the physiological factors contributing to VO2max, more specifically oxygen delivery, and the impacts on performance.
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Govender I, Nashed KK, Rangiah S, Okeke S, Maphasha OM. Palpitations: Evaluation and management by primary care practitioners. S Afr Fam Pract (2004) 2022; 64:e1-e8. [PMID: 35261258 PMCID: PMC8905373 DOI: 10.4102/safp.v64i1.5449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 01/20/2022] [Accepted: 01/23/2022] [Indexed: 12/05/2022] Open
Abstract
Palpitations are a common, non-specific presenting complaint in primary healthcare and emergency departments. Palpitations are mostly a symptom of benign underlying disease but a sign of life-threatening conditions. Importantly, palpitations are a symptom and not a diagnosis, and cardiac causes are the most concerning aetiology. Clinicians should seek to identify the underlying cause. History and physical examination are important in the assessment of patients with palpitations, and the use of a 12-lead electrographic (ECG) monitor on presentation is the gold standard of diagnosis. If the aetiology cannot be determined, an ambulatory Holter 24–48-h monitor can be used. Treatment and follow-up of patients presenting with palpitations as the main complaint will depend on the aetiology and investigation findings. Patients with palpitations accompanied by dizziness, excessive fatigue, or chest pains should receive adequate acute care aiming to stabilise their condition before referring to a higher level of care.
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Affiliation(s)
- Indiran Govender
- Department Family Medicine and Primary Health Care, Faculty Health Sciences, Sefako Makgatho Health Sciences University, Pretoria.
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Bourne KM, Hall J, Stiles LE, Sheldon RS, Shibao CA, Okamoto LE, Garland EM, Gamboa AC, Peltier A, Diedrich A, Biaggioni I, Robertson D, Raj SR. Symptom Presentation and Access to Medical Care in Patients With Postural Orthostatic Tachycardia Syndrome: Role of Sex. CJC Open 2022; 3:S44-S52. [PMID: 34993433 PMCID: PMC8712580 DOI: 10.1016/j.cjco.2021.08.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 08/25/2021] [Indexed: 01/12/2023] Open
Abstract
Background Postural orthostatic tachycardia syndrome (POTS) is a chronic form of orthostatic intolerance that primarily impacts female patients of childbearing age. The role of sex differences in POTS is not well understood. We sought to identify sex differences in diagnosis, symptoms, comorbidities, and treatments in female and male patients diagnosed with POTS. Methods A comprehensive survey was designed in partnership by Dysautonomia International (East Moriches, NY) and Vanderbilt University Medical Center (Nashville, TN). Patients were recruited through Dysautonomia International’s website and social media channels. The survey was delivered online through a secure research data capture database. Responses were analyzed according to biological sex. Continuous variables are presented as median (25th percentile-75th percentile), and categorical variables are presented as number and proportion of participants. Results A total of 8919 patients reported a physician diagnosis of POTS and were included in this analysis. The majority of respondents were female (93.7%). Female and male patients experienced misdiagnosis at similar rates (76.2% vs 74.9%, P = 0.5) and saw a similar number of doctors before diagnosis (5 [3-8] vs 5 [3-8], P = 0.9). Despite these similarities, diagnostic delay was longer for female, compared with male, patients (1.50 [0.25-5.25] years vs 0.92 [0.08-2.91] years, P < 0.001). Conclusions Despite the primarily female demographic of POTS patients, female patients experience more challenges with diagnosis than male patients. Increased awareness and recognition of POTS may help to reduce the diagnostic challenges in both female and male patients, and improve treatment and management for individuals living with this debilitating disorder.
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Affiliation(s)
- Kate M Bourne
- Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada
| | - Juliette Hall
- Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada
| | - Lauren E Stiles
- Dysautonomia International, East Moriches, New York, USA.,Department of Neurology, Stony Brook University, Stony Brook, New York, USA
| | - Robert S Sheldon
- Autonomic Dysfunction Center, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Cyndya A Shibao
- Autonomic Dysfunction Center, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Luis E Okamoto
- Autonomic Dysfunction Center, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Emily M Garland
- Autonomic Dysfunction Center, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Alfredo C Gamboa
- Autonomic Dysfunction Center, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Amanda Peltier
- Autonomic Dysfunction Center, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Andre Diedrich
- Autonomic Dysfunction Center, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Italo Biaggioni
- Autonomic Dysfunction Center, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - David Robertson
- Autonomic Dysfunction Center, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Satish R Raj
- Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada.,Autonomic Dysfunction Center, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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Robinson AT, Wenner MM, Charkoudian N. Differential influences of dietary sodium on blood pressure regulation based on race and sex. Auton Neurosci 2021; 236:102873. [PMID: 34509133 PMCID: PMC8627459 DOI: 10.1016/j.autneu.2021.102873] [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] [Received: 02/28/2021] [Revised: 07/19/2021] [Accepted: 08/23/2021] [Indexed: 11/30/2022]
Abstract
There are clear differences between men and women, and differences among races, in the incidence and prevalence of hypertension. Furthermore, there is extensive inter-individual variability among humans in the extent to which sodium ingestion alters blood pressure. Orthostatic intolerance and orthostatic hypotension are more common in women; these are often treated with a high salt diet, which has variable efficacy in increasing blood volume and blood pressure. Conversely, people with certain forms of hypertension are often counseled to decrease their sodium intake. Non-Hispanic Black men and women have higher rates of hypertension compared to non-Hispanic White men and women and other racial/ethnic groups. In aggregate, Black women appear to have better orthostatic tolerance than White women. In the present paper, we summarize and evaluate the current evidence for mechanisms of blood pressure regulation in men and women, as well as differences between Black and White groups, with a focus on cardiovascular responses to salt and differences among these groups. We also provide a brief review of factors that are not traditionally considered to be "biological" - such as socio-economic disparities resulting from historic and contemporary inequity across racial groups. These non-biological factors have direct and substantial influences on cardiovascular mechanisms, as well as implications for the influences of salt and sodium intake on blood pressure and cardiovascular health. We conclude that both biological and socio-economic factors provide critical modulating influences when considering the impacts of sodium on cardiovascular health as functions of race and sex.
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Affiliation(s)
- Austin T Robinson
- Neurovascular Physiology Laboratory, School of Kinesiology, Auburn University, Auburn, AL 36849, United States of America.
| | - Megan M Wenner
- Women's Cardiovascular Research Laboratory, Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE 19713, United States of America
| | - Nisha Charkoudian
- Thermal & Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, MA 01760, United States of America
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Madill SA. Transient Visual Loss in Young Females with Crowded Optic Discs: A Proposed Aetiology. Neuroophthalmology 2021; 45:372-379. [PMID: 34720267 DOI: 10.1080/01658107.2021.1937231] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
I present four cases of transient visual loss (TVL) in young females with crowded optic discs. One patient had asymmetrical cup-to-disc ratios and only experienced TVL in the eye with the more crowded disc. I review the evidence for blood flow autoregulatory dysfunction within crowded optic discs in combination with reduced ocular perfusion pressure to propose a possible aetiology for both unilateral and bilateral TVL in young females with crowded optic discs.
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Affiliation(s)
- Stephen A Madill
- Princess Alexandra Eye Pavilion, Lothian Universities NHS Trust, Edinburgh, UK
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10
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Sex differences in blood pressure regulation during the isometric exercise under heated environment. Blood Press Monit 2021; 27:55-62. [PMID: 34569989 DOI: 10.1097/mbp.0000000000000566] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In the absence of heat stress, females increase blood pressure (BP) during isometric handgrip exercise due to cardiac output more than total peripheral resistance (TPR) compared to men. Although heat stress seems to blunt BP responses at rest and during handgrip, possible sex differences remained unknown. We hypothesized that BP responses during handgrip under a heated environment (HOT) will be different between men and women. Eight healthy men (29 ± 6 years) and eight women (26 ± 4 years) participated in this study. The experimental protocol was separated into two environmental conditions: HOT (~ 36 °C) and thermoneutral (TC; ~ 24 °C). In both conditions, participants rested for 30 min and performed the handgrip for 3 min. BP, heart rate (HR) stroke volume and cardiac output were continuously recorded, and TPR was calculated (TPR = mean blood pressure (MBP)/cardiac output). HOT reduced BP and TPR at baseline and during handgrip in females as compared to TC, while males showed similar responses in both thermal conditions. HR was higher under HOT in both groups. Cardiac output and stroke volume were not different under HOT compared to TC for females. In males, cardiac output increased at the last minute of handgrip under HOT through augmented HR, because stroke volume was unchanged. In conclusion, the main effect of HOT was to shift downwards BP and total peripheral resistance at rest and during isometric exercise in females. In males, the combination of handgrip and HOT increased cardiac output by augmented HR, whereas BP presented similar responses between thermal conditions during handgrip.
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Taylor CE, Arnold AC, Fanciulli A, Provini F, Fu Q, Macefield VG, Weese-Mayer DE, Shibao C, Charkoudian N, Claydon VE. Women in clinical autonomic research and the autonomic societies: how far have we come in thirty years? Clin Auton Res 2021; 31:23-26. [PMID: 33454833 PMCID: PMC7811683 DOI: 10.1007/s10286-021-00768-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Accepted: 01/04/2021] [Indexed: 11/28/2022]
Affiliation(s)
- Chloe E Taylor
- School of Health Sciences, Western Sydney University, Sydney, Australia.
| | - Amy C Arnold
- Department of Neural and Behavioral Sciences, Pennsylvania State University College of Medicine, Hershey, PA, USA
| | | | - Federica Provini
- IRCCS Istituto Delle Scienze Neurologiche Di Bologna, UOC Clinica Neurologica NeuroMet, Ospedale Bellaria, Via Altura 3, 40139, Bologna, Italy
| | - Qi Fu
- Women's Heart Health Laboratory, Institute for Exercise and Environmental Medicine at Texas Health Presbyterian Hospital, Dallas, TX, USA
- The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | | | - Debra E Weese-Mayer
- Division of Autonomic Medicine, Center for Autonomic Medicine in Pediatrics (CAMP), Department of Pediatrics, Ann & Robert H. Lurie Children's Hospital of Chicago and Stanley Manne Children's Research Institute, Chicago, IL, USA
- Department of Pediatrics, Pediatric Autonomic Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Cyndya Shibao
- Division of Clinical Pharmacology and Autonomic Dysfunction Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Nisha Charkoudian
- U.S. Army Research Institute of Environmental Medicine, Natick, MA, USA
| | - Victoria E Claydon
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
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12
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Lim CL. Fundamental Concepts of Human Thermoregulation and Adaptation to Heat: A Review in the Context of Global Warming. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:E7795. [PMID: 33114437 PMCID: PMC7662600 DOI: 10.3390/ijerph17217795] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/16/2020] [Accepted: 10/20/2020] [Indexed: 12/18/2022]
Abstract
The international community has recognized global warming as an impending catastrophe that poses significant threat to life on earth. In response, the signatories of the Paris Agreement (2015) have committed to limit the increase in global mean temperature to < 1.5 °C from pre-industry period, which is defined as 1950-1890. Considering that the protection of human life is a central focus in the Paris Agreement, the naturally endowed properties of the human body to protect itself from environmental extremes should form the core of an integrated and multifaceted solution against global warming. Scholars believe that heat and thermoregulation played important roles in the evolution of life and continue to be a central mechanism that allows humans to explore, labor and live in extreme conditions. However, the international effort against global warming has focused primarily on protecting the environment and on the reduction of greenhouse gases by changing human behavior, industrial practices and government policies, with limited consideration given to the nature and design of the human thermoregulatory system. Global warming is projected to challenge the limits of human thermoregulation, which can be enhanced by complementing innate human thermo-plasticity with the appropriate behavioral changes and technological innovations. Therefore, the primary aim of this review is to discuss the fundamental concepts and physiology of human thermoregulation as the underlying bases for human adaptation to global warming. Potential strategies to extend human tolerance against environmental heat through behavioral adaptations and technological innovations will also be discussed. An important behavioral adaptation postulated by this review is that sleep/wake cycles would gravitate towards a sub-nocturnal pattern, especially for outdoor activities, to avoid the heat in the day. Technologically, the current concept of air conditioning the space in the room would likely steer towards the concept of targeted body surface cooling. The current review was conducted using materials that were derived from PubMed search engine and the personal library of the author. The PubMed search was conducted using combinations of keywords that are related to the theme and topics in the respective sections of the review. The final set of articles selected were considered "state of the art," based on their contributions to the strength of scientific evidence and novelty in the domain knowledge on human thermoregulation and global warming.
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Affiliation(s)
- Chin Leong Lim
- Lee Kong Chian School of Medicine, Nanyang Technological University, 11 Mandalay Road, Singapore 308232, Singapore
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13
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Sugawara J, Tomoto T. Effects of short-term warm water immersion on cardiac baroreflex sensitivity in healthy men. J Physiol Sci 2020; 70:34. [PMID: 32646375 PMCID: PMC10717741 DOI: 10.1186/s12576-020-00762-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 07/03/2020] [Indexed: 11/10/2022]
Abstract
Warm water immersion (WWI) causes dizziness presumably due to a substantial drop of blood pressure. The aim of this study was to elucidate the effects of short-term WWI on cardiac baroreflex sensitivity (BRS) and the contribution of arterial stiffness to the cardiac BRS. Twelve apparent healthy men (44 ± 12 years) performed the single stand-up test after 5-min sitting in the bathtub without (Control) and with 41 °C warm water at the heart level (WWI). Cardiac BRS gain was evaluated by R-R interval response to the standing-induced drop of systolic blood pressure. In addition, before and 10 min after the single stand-up test, carotid arterial β-stiffness index was evaluated in the supine rest. BRS gain was blunted (2.9 ± 1.6 vs. 1.8 ± 1.1 ms/mmHg, P = 0.005), whereas β-stiffness index was not changed significantly after WWI. BRS gain correlated with β-stiffness index before (r = - 0.626, P = 0.028) and after WWI (r = - 0.672, P = 0.015). ANCOVA revealed that these slopes of linear regression lines remained unchanged after WWI (P = 0.350). These results indicate that a short-term WWI acutely deteriorates cardiac BRS. Individuals with stiffer arteries are relatively more susceptible to WWI because of their poor baseline BRS, which might be one of the causes of bathing-related falling in elderly persons as well as frailty.
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Affiliation(s)
- Jun Sugawara
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8566, Japan.
| | - Tsubasa Tomoto
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX, USA
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Yanovich R, Ketko I, Charkoudian N. Sex Differences in Human Thermoregulation: Relevance for 2020 and Beyond. Physiology (Bethesda) 2020; 35:177-184. [PMID: 32293229 DOI: 10.1152/physiol.00035.2019] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The participation of women in physically strenuous athletic and occupational tasks has increased substantially in the past decade. Female sex steroids have influences on thermoregulatory processes that could impact physical performance in the heat. Here, we summarize and evaluate the current literature regarding sex differences in thermoregulation and provide recommendations for heat-illness risk-mitigation strategies.
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Affiliation(s)
- R Yanovich
- The Institute of Military Physiology, Israel Defense Forces, Medical Corps, Tel-Hashomer, Israel
- Heller Institute of Medical Research, Sheba Medical Center, Tel-Hashomer, Israel
- Department of Military Medicine, Faculty of Medicine, Hebrew University, Jerusalem, Israel
- The Academic College at Wingate, Wingate Institute, Netanya, Israel
| | - I Ketko
- The Institute of Military Physiology, Israel Defense Forces, Medical Corps, Tel-Hashomer, Israel
- Heller Institute of Medical Research, Sheba Medical Center, Tel-Hashomer, Israel
| | - N Charkoudian
- U.S. Army Research Institute of Environmental Medicine, Natick, Massachussetts
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15
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Junghans-Rutelonis AN, Postier A, Warmuth A, Schwantes S, Weiss KE. Pain Management In Pediatric Patients With Postural Orthostatic Tachycardia Syndrome: Current Insights. J Pain Res 2019; 12:2969-2980. [PMID: 31802934 PMCID: PMC6827519 DOI: 10.2147/jpr.s194391] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Accepted: 09/21/2019] [Indexed: 11/23/2022] Open
Abstract
Pediatric patients with postural orthostatic tachycardia syndrome (POTS) often present with co-occurring struggles with chronic pain (POTS+pain) that may limit daily activities. POTS is a clinical syndrome characterized by orthostatic symptoms and excessive postural tachycardia without orthostatic hypotension. Active research from the medical and scientific community has led to controversy over POTS diagnosis and treatment, yet patients continue to present with symptoms associated with POTS+pain, making treatment recommendations critical. This topical review examines the literature on diagnosing and treating pediatric POTS+pain and the challenges clinicians face. Most importantly, clinicians must employ an interdisciplinary team approach to determine the ideal combination of pharmacologic (e.g., fludrocortisone), non-pharmacologic (e.g., physical therapy, integrative medicine), and psychological (e.g., cognitive behavioral therapy, psychoeducation) treatment approaches that acknowledge the complexity of the child's condition, while simultaneously tailoring these approaches to the child's personal needs. We provide recommendations for treatment for youth with POTS+pain based on the current literature.
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Affiliation(s)
- Ashley N Junghans-Rutelonis
- Department of Pain Medicine, Palliative Care, and Integrative Medicine, Children's Hospitals and Clinics of Minnesota, Minneapolis, MN, USA
| | - Andrea Postier
- Department of Pain Medicine, Palliative Care, and Integrative Medicine, Children's Hospitals and Clinics of Minnesota, Minneapolis, MN, USA.,Children's Minnesota Research Institute, Children's Hospitals and Clinics of Minnesota, Minneapolis, MN, USA
| | - Andrew Warmuth
- Department of Pain Medicine, Palliative Care, and Integrative Medicine, Children's Hospitals and Clinics of Minnesota, Minneapolis, MN, USA.,Department of Physical Medicine and Rehabilitation, Children's Hospitals and Clinics of Minnesota, Minneapolis, MN, USA
| | - Scott Schwantes
- Department of Pain Medicine, Palliative Care, and Integrative Medicine, Children's Hospitals and Clinics of Minnesota, Minneapolis, MN, USA
| | - Karen E Weiss
- Department of Anesthesiology and Pain Medicine, University of Washington School of Medicine & Seattle Children's Hospital, Seattle, DC, USA
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16
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Labrecque L, Rahimaly K, Imhoff S, Paquette M, Le Blanc O, Malenfant S, Drapeau A, Smirl JD, Bailey DM, Brassard P. Dynamic cerebral autoregulation is attenuated in young fit women. Physiol Rep 2019; 7:e13984. [PMID: 30652420 PMCID: PMC6335382 DOI: 10.14814/phy2.13984] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 12/28/2018] [Indexed: 02/07/2023] Open
Abstract
Young women exhibit higher prevalence of orthostatic hypotension with presyncopal symptoms compared to men. These symptoms could be influenced by an attenuated ability of the cerebrovasculature to respond to rapid blood pressure (BP) changes [dynamic cerebral autoregulation (dCA)]. The influence of sex on dCA remains unclear. dCA in 11 fit women (25 ± 2 years) and 11 age-matched men (24 ± 1 years) was compared using a multimodal approach including a sit-to-stand (STS) and forced BP oscillations (repeated squat-stand performed at 0.05 and 0.10 Hz). Prevalence of initial orthostatic hypotension (IOH; decrease in systolic ≥ 40 mmHg and/or diastolic BP ≥ 20 mmHg) during the first 15 sec of STS was determined as a functional outcome. In women, the decrease in mean middle cerebral artery blood velocity (MCAvmean ) following the STS was greater (-20 ± 8 vs. -11 ± 7 cm sec-1 ; P = 0.018) and the onset of the regulatory change (time lapse between the beginning of the STS and the increase in the conductance index (MCAvmean /mean arterial pressure) was delayed (P = 0.007). Transfer function analysis gain during 0.05 Hz squat-stand was ~48% higher in women (6.4 ± 1.3 vs. 3.8 ± 2.3 cm sec-1 mmHg-1 ; P = 0.017). Prevalence of IOH was comparable between groups (women: 4/9 vs. men: 5/9, P = 0.637). These results indicate the cerebrovasculature of fit women has an attenuated ability to react to rapid changes in BP in the face of preserved orthostasis, which could be related to higher resting cerebral blood flow allowing women to better face transient hypotension.
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Affiliation(s)
- Lawrence Labrecque
- Department of KinesiologyFaculty of MedicineUniversité LavalQuébecCanada
- Research center of the Institut universitaire de cardiologie et de pneumologie de QuébecQuébecCanada
| | - Kevan Rahimaly
- Department of KinesiologyFaculty of MedicineUniversité LavalQuébecCanada
- Research center of the Institut universitaire de cardiologie et de pneumologie de QuébecQuébecCanada
| | - Sarah Imhoff
- Department of KinesiologyFaculty of MedicineUniversité LavalQuébecCanada
- Research center of the Institut universitaire de cardiologie et de pneumologie de QuébecQuébecCanada
| | - Myriam Paquette
- Department of KinesiologyFaculty of MedicineUniversité LavalQuébecCanada
- Research center of the Institut universitaire de cardiologie et de pneumologie de QuébecQuébecCanada
| | - Olivier Le Blanc
- Department of KinesiologyFaculty of MedicineUniversité LavalQuébecCanada
- Research center of the Institut universitaire de cardiologie et de pneumologie de QuébecQuébecCanada
| | - Simon Malenfant
- Department of KinesiologyFaculty of MedicineUniversité LavalQuébecCanada
- Research center of the Institut universitaire de cardiologie et de pneumologie de QuébecQuébecCanada
| | - Audrey Drapeau
- Department of KinesiologyFaculty of MedicineUniversité LavalQuébecCanada
- Research center of the Institut universitaire de cardiologie et de pneumologie de QuébecQuébecCanada
| | - Jonathan D. Smirl
- Concussion Research LaboratoryHealth and Exercise SciencesUniversity of British Columbia OkanaganBritish ColumbiaCanada
| | - Damian M. Bailey
- Neurovascular Research LaboratoryFaculty of Life Sciences and EducationUniversity of South WalesSouth WalesUnited Kingdom
| | - Patrice Brassard
- Department of KinesiologyFaculty of MedicineUniversité LavalQuébecCanada
- Research center of the Institut universitaire de cardiologie et de pneumologie de QuébecQuébecCanada
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17
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Mansur DE, Campos MO, Mattos JD, Paiva ACS, Rocha MP, Videira RLR, Macefield VG, Nóbrega ACL, Fernandes IA. Muscle sympathetic nerve activity and hemodynamic responses to venous distension: does sex play a role? Am J Physiol Heart Circ Physiol 2018; 316:H734-H742. [PMID: 30592900 DOI: 10.1152/ajpheart.00702.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Peripheral venous distension mechanically stimulates type III/IV sensory fibers in veins and evokes pressor and sympathoexcitatory reflex responses in humans. As young women have reduced venous compliance and impaired sympathetic transduction, we tested the hypothesis that pressor and sympathoexcitatory responses to venous distension may be attenuated in women compared with men. Mean arterial pressure (photoplethysmography), heart rate (HR), stroke volume (SV; Modelflow), cardiac output (CO = HR × SV), muscle sympathetic nerve activity (MSNA), femoral artery blood flow, and femoral artery conductance (Doppler ultrasound) were quantified in eight men (27 ± 4 yr) and nine women (28 ± 4 yr) before [control (CON)], during (INF), and immediately after (post-INF) a local infusion of saline [5% of the total forearm volume (30 ml/min); the infusion time was 2 ± 1 and 1 ± 1 min ( P = 0.0001) for men and women, respectively] through a retrograde catheter inserted into an antecubital vein, to which venous drainage and arterial supply had been occluded. Mean arterial pressure increased during and after infusion in both groups (vs. the CON group, P < 0.05), but women showed a smaller pressor response in the post-INF period (Δ+7.2 ± 2.0 vs. Δ+18.3 ± 3.9 mmHg in men, P = 0.019). MSNA increased and femoral artery conductance decreased similarly in both groups (vs. the CON group, P < 0.05) at post-INF. Although HR changes were similar, increases in SV (Δ+20.4 ± 8.6 vs. Δ+2.6 ± 2.7 ml, P = 0.05) and CO (Δ+0.84 ± 0.17 vs. Δ+0.34 ± 0.10 l/min, P = 0.024) were greater in men compared with women. Therefore, venous distension evokes a smaller pressor response in young women due to attenuated cardiac adjustments rather than reduced venous compliance or sympathetic transduction. NEW & NOTEWORTHY We found that the pressor response to venous distension was attenuated in young women compared with age-matched men. This was due to attenuated cardiac adjustments rather than reduced venous compliance, sympathetic activation, or impaired transduction and vascular control. Collectively, these findings suggest that an attenuated venous distension reflex could be involved in orthostatic intolerance in young women.
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Affiliation(s)
- Daniel E Mansur
- Laboratory of Exercise Sciences, Fluminense Federal University , Niterói , Brazil
| | - Monique O Campos
- Laboratory of Exercise Sciences, Fluminense Federal University , Niterói , Brazil
| | - João D Mattos
- Laboratory of Exercise Sciences, Fluminense Federal University , Niterói , Brazil
| | - Adrielle C S Paiva
- Laboratory of Exercise Sciences, Fluminense Federal University , Niterói , Brazil
| | - Marcos P Rocha
- Laboratory of Exercise Sciences, Fluminense Federal University , Niterói , Brazil
| | | | - Vaughan G Macefield
- College of Medicine, Mohammed Bin Rashid University of Health and Medicine , Dubai , United Arab Emirates.,Baker Heart and Diabetes Institute , Melbourne, Victoria , Australia
| | - Antonio C L Nóbrega
- Laboratory of Exercise Sciences, Fluminense Federal University , Niterói , Brazil
| | - Igor A Fernandes
- Laboratory of Exercise Sciences, Fluminense Federal University , Niterói , Brazil.,NeuroV̇ASQ̇-Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília , Brasília , Brazil
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18
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Abstract
Sex and gender, as biological and social factors, significantly influence health outcomes. Among the biological factors, sex differences in vascular physiology may be one specific mechanism contributing to the observed differences in clinical presentation, response to treatment, and clinical outcomes in several vascular disorders. This review focuses on the cerebrovascular bed and summarizes the existing literature on sex differences in cerebrovascular hemodynamics to highlight the knowledge deficit that exists in this domain. The available evidence is used to generate mechanistically plausible and testable hypotheses to underscore the unmet need in understanding sex-specific mechanisms as targets for more effective therapeutic and preventive strategies.
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Affiliation(s)
- Cristina Duque
- Division of Stroke and Neurocritical Care, Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois.,Department of Neurology, Coimbra University Hospital Center, Coimbra, Portugal
| | - Steven K Feske
- Division of Stroke, Department of Neurology, Brigham and Women's Hospital, Boston, Massachusetts
| | - Farzaneh A Sorond
- Division of Stroke and Neurocritical Care, Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
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19
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Abidi S, Nili M, Serna S, Kim S, Hazlett C, Edgell H. Influence of sex, menstrual cycle, and oral contraceptives on cerebrovascular resistance and cardiorespiratory function during Valsalva or standing. J Appl Physiol (1985) 2017; 123:375-386. [PMID: 28522756 DOI: 10.1152/japplphysiol.00035.2017] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 05/11/2017] [Accepted: 05/16/2017] [Indexed: 01/11/2023] Open
Abstract
Women experience orthostatic intolerance more than men, and they experience faintness more in the early follicular [i.e., low-hormone (LH)] than luteal [i.e., high-hormone (HH)] phase of the menstrual cycle. Men (n = 13, 25.8 ± 1.8 yr old) and women in the LH (days 2-5; placebo) and HH (days 18-24; high dose) phases of the menstrual cycle with (OC; n = 14, 22.0 ± 0.8 yr old) or without (NOC; n = 12, 21.8 ± 0.5 yr old) oral contraceptive (OC) use underwent the Valsalva maneuver and a supine-sit-stand protocol. Blood pressure, normalized stroke volume [stroke volume index (SVi)], cardiac output index, heart rate, end-tidal CO2, and middle cerebral artery (MCA) blood flow velocity were measured. When subjected to the Valsalva maneuver, all women had a greater increase in diastolic and mean MCA blood flow velocity than men (P ≤ 0.065), with no significant effect of menstrual cycle phase or OC use. When subjected to the supine-sit-stand protocol, men had lower MCA blood flow velocity (P < 0.038) than all women, and SVi was higher in men than in the NOC group in all postures (P < 0.011) and in the OC group in the LH phase of the menstrual cycle during standing (P = 0.010). Only men experienced higher resistance index (P < 0.001) and pulsatility index (P < 0.001) with standing. The OC group had lower end-tidal CO2 (P = 0.002) than the NOC group (P = 0.030) and men (P ≤ 0.067). SVi (P = 0.004) and cardiac output index (P = 0.008) were higher in the OC than NOC group. A tendency toward a lower mean MCA blood flow velocity (P = 0.058) and higher SVi (P = 0.059) and pulsatility index (P = 0.058) was noted in the HH than LH phase. Mean arterial pressure was higher in the OC than NOC group in the LH phase (P = 0.049) and lower in the HH than LH phase (P = 0.014). Our results indicate that cycling estrogens/progestins can influence ventilatory, cardiovascular, and/or cerebrovascular physiology.NEW & NOTEWORTHY We have found sex differences in the cerebrovascular response to the Valsalva maneuver and standing. Men have greater cerebral vasoconstriction (or women have greater cerebral vasodilation) during late phase II of the Valsalva maneuver, and the cerebrovascular resistance index increases in men, but not in women, during standing. Furthermore, our findings indicate that both the menstrual cycle phase and oral contraceptive use can influence cardiovascular function both at rest and during active standing.
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Affiliation(s)
- Syed Abidi
- School of Kinesiology and Health Sciences, York University, Toronto, Ontario, Canada; and
| | - Misha Nili
- School of Kinesiology and Health Sciences, York University, Toronto, Ontario, Canada; and
| | - Stephania Serna
- School of Kinesiology and Health Sciences, York University, Toronto, Ontario, Canada; and
| | - Simon Kim
- School of Kinesiology and Health Sciences, York University, Toronto, Ontario, Canada; and
| | - Christopher Hazlett
- School of Kinesiology and Health Sciences, York University, Toronto, Ontario, Canada; and
| | - Heather Edgell
- School of Kinesiology and Health Sciences, York University, Toronto, Ontario, Canada; and .,Muscle Health Research Centre, York University, Toronto, Ontario, Canada
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20
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Briant LJB, Charkoudian N, Hart EC. Sympathetic regulation of blood pressure in normotension and hypertension: when sex matters. Exp Physiol 2016; 101:219-29. [PMID: 26682826 DOI: 10.1113/ep085368] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 12/14/2015] [Indexed: 12/21/2022]
Abstract
NEW FINDINGS What is the topic of this review? Hypertension is a major problem in Western society. Risk of hypertension increases with age, especially in women, who have lower risk compared with men until menopause. This review outlines the sex differences in the sympathetic control of blood pressure and how these mechanisms change with age. What advances does it highlight? It has recently been recognized that men and women regulate blood pressure by different physiological mechanisms. This is important for both the understanding and the clinical management of individual patients with hypertension. This review summarizes recent advances in understanding how the regulation of blood pressure in hypertension by the sympathetic nervous system differs between men and women. The sympathetic nervous system has a central role in the regulation of arterial blood pressure (BP) and in the development of hypertension in humans. Recent evidence points to differences between the sexes in the integrative mechanisms by which BP is controlled, suggesting that the development of hypertension may follow distinct pathways in women compared with men. An important aspect of sympathetic control of BP is its substantial interindividual variability. In healthy young men, the variability in sympathetic nerve activity (SNA) is balanced by variability in cardiac output and vascular adrenergic responses, such that BP remains similar, and normal, across a severalfold range of resting SNA values. In young women, variability in resting SNA is similar to that seen in men, but the 'balancing' mechanisms are strikingly different; women exhibit greater β-adrenergic vasodilatation compared with men, which minimizes the pressor effects of a given level of SNA. Ageing is associated with increased SNA and a loss of the balancing factors seen in younger people, leading to an increased risk of hypertension in older people. Loss of oestrogen with menopause in women appears to be linked mechanistically with the decrease in β-adrenergic vasodilatation and the increased risk of hypertension in older women. Other important factors contributing to hypertension via sympathetic mechanisms are obesity and arterial stiffening, both of which increase with ageing. We conclude with a discussion of important areas in which more work is needed to understand and manage appropriately the sex-specific mechanisms in the development and maintenance of hypertension.
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Affiliation(s)
- L J B Briant
- Clinical Research and Imaging Centre, Cardionomics Group, University of Bristol, Bristol, UK
| | - N Charkoudian
- US Army Research Institute of Environmental Medicine, Natick, MA, USA
| | - E C Hart
- Clinical Research and Imaging Centre, Cardionomics Group, University of Bristol, Bristol, UK
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21
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Joyner MJ, Wallin BG, Charkoudian N. Sex differences and blood pressure regulation in humans. Exp Physiol 2015; 101:349-55. [DOI: 10.1113/ep085146] [Citation(s) in RCA: 122] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 07/02/2015] [Indexed: 01/26/2023]
Affiliation(s)
| | - B. Gunnar Wallin
- Institute of Neuroscience and Physiology; The Sahlgren Academy at Gothenburg University; Göteborg Sweden
| | - Nisha Charkoudian
- Thermal and Mountain Medicine Division; US Army Research Institute of Environmental Medicine; Natick MA USA
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22
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Sladek CD, Michelini LC, Stachenfeld NS, Stern JE, Urban JH. Endocrine‐Autonomic Linkages. Compr Physiol 2015; 5:1281-323. [DOI: 10.1002/cphy.c140028] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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23
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Dereli N, Tutal ZB, Babayigit M, Kurtay A, Sahap M, Horasanli E. [Effect of intraoperative esmolol infusion on anesthetic, analgesic requirements and postoperative nausea-vomitting in a group of laparoscopic cholecystectomy patients]. Braz J Anesthesiol 2015; 65:141-6. [PMID: 25592140 DOI: 10.1016/j.bjan.2014.08.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 08/06/2014] [Indexed: 12/27/2022] Open
Abstract
PURPOSE Postoperative pain and nausea/vomitting (PNV) are common in laparoscopic cholecystectomy patients. Sympatholytic agents might decrease requirements for intravenous or inhalation anesthetics and opioids. In this study we aimed to analyze effects of esmolol on intraoperative anesthetic-postoperative analgesic requirements, postoperative pain and PNV. METHODS Sixty patients have been included. Propofol, remifentanil and vecuronium were used for induction. Study groups were as follows; I - Esmolol infusion was added to maintenance anesthetics (propofol and remifentanil), II - Only propofol and remifentanil was used during maintenance, III - Esmolol infusion was added to maintenance anesthetics (desflurane and remifentanil), IV - Only desflurane and remifentanil was used during maintenance. They have been followed up for 24h for PNV and analgesic requirements. Visual analog scale (VAS) scores for pain was also been evaluated. RESULTS VAS scores were significantly lowest in group I (p=0.001-0.028). PNV incidence was significantly lowest in group I (p=0.026). PNV incidence was also lower in group III compared to group IV (p=0.032). Analgesic requirements were significantly lower in group I and was lower in group III compared to group IV (p=0.005). Heart rates were significantly lower in esmolol groups (group I and III) compared to their controls (p=0.001) however blood pressures were similar in all groups (p=0.594). Comparison of esmolol groups with controls revealed that there is a significant decrease in anesthetic and opioid requirements (p=0.024-0.03). CONCLUSION Using esmolol during anesthetic maintenance significantly decreases anesthetic-analgesic requirements, postoperative pain and PNV.
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Affiliation(s)
- Necla Dereli
- Departamento de Anestesiologia e Reanimação, Hospital de Treinamento e Pesquisa Kecioren, Ankara, Turquia
| | - Zehra Baykal Tutal
- Departamento de Anestesiologia e Reanimação, Hospital de Treinamento e Pesquisa Kecioren, Ankara, Turquia.
| | - Munire Babayigit
- Departamento de Anestesiologia e Reanimação, Hospital de Treinamento e Pesquisa Kecioren, Ankara, Turquia
| | - Aysun Kurtay
- Departamento de Anestesiologia e Reanimação, Hospital de Treinamento e Pesquisa Kecioren, Ankara, Turquia
| | - Mehmet Sahap
- Departamento de Anestesiologia e Reanimação, Hospital de Treinamento e Pesquisa Kecioren, Ankara, Turquia
| | - Eyup Horasanli
- Departamento de Anestesiologia e Reanimação, Hospital de Treinamento e Pesquisa Kecioren, Ankara, Turquia
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24
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Joyner MJ, Barnes JN, Hart EC, Wallin BG, Charkoudian N. Neural control of the circulation: how sex and age differences interact in humans. Compr Physiol 2015; 5:193-215. [PMID: 25589269 PMCID: PMC4459710 DOI: 10.1002/cphy.c140005] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The autonomic nervous system is a key regulator of the cardiovascular system. In this review, we focus on how sex and aging influence autonomic regulation of blood pressure in humans in an effort to understand general issues related to the cardiovascular system as a whole. Younger women generally have lower blood pressure and sympathetic activity than younger men. However, both sexes show marked interindividual variability across age groups with significant overlap seen. Additionally, while men across the lifespan show a clear relationship between markers of whole body sympathetic activity and vascular resistance, such a relationship is not seen in young women. In this context, the ability of the sympathetic nerves to evoke vasoconstriction is lower in young women likely as a result of concurrent β2-mediated vasodilation that offsets α-adrenergic vasoconstriction. These differences reflect both central sympatho-inhibitory effects of estrogen and also its influence on peripheral vasodilation at the level of the vascular smooth muscle and endothelium. By contrast postmenopausal women show a clear relationship between markers of whole body sympathetic traffic and vascular resistance, and sympathetic activity rises progressively in both sexes with aging. These major findings in humans are discussed in the context of differences in population-based trends in blood pressure and orthostatic intolerance. The many areas where there is little sex-specific data on how the autonomic nervous system participates in the regulation of the human cardiovascular system are highlighted.
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Affiliation(s)
| | - Jill N. Barnes
- Department of Anesthesiology, Mayo Clinic, Rochester, MN
| | - Emma C. Hart
- School of Physiology and Pharmacology, University of Bristol, Bristol UK
| | - B. Gunnar Wallin
- Institute of Neuroscience and Physiology, The Sahlgren Academy at Gothenburg University, Goteborg, Sweden
| | - Nisha Charkoudian
- Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA
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25
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Adverse Drug Reactions and Expected Effects to Therapy with Subcutaneous Mistletoe Extracts (Viscum album L.) in Cancer Patients. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2014; 2014:724258. [PMID: 24672577 PMCID: PMC3929984 DOI: 10.1155/2014/724258] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 12/16/2013] [Indexed: 11/17/2022]
Abstract
Background. In Europe, mistletoe extracts are widely used as a complementary cancer therapy. We assessed the safety of subcutaneous mistletoe as a conjunctive therapy in cancer patients within an anthroposophic medicine setting in Germany. Methods. A multicentre, observational study was performed within the Network Oncology. Suspected mistletoe adverse drug reactions (ADRs) were described by frequency, causality, severity, and seriousness. Potential risk factors, dose relationships and drug-drug interactions were investigated. Results. Of 1923 cancer patients treated with subcutaneous mistletoe extracts, 283 patients (14.7%) reported 427 expected effects (local reactions <5 cm and increased body temperature <38°C). ADRs were documented in 162 (8.4%) patients who reported a total of 264 events. ADRs were mild (50.8%), moderate (45.1%), or severe (4.2%). All were nonserious. Logistic regression analysis revealed that expected effects were more common in females, while immunoreactivity decreased with increasing age and tumour stage. No risk factors were identified for ADRs. ADR frequency increased as mistletoe dose increased, while fewer ADRs occurred during mistletoe therapy received concurrent with conventional therapies. Conclusion. The results of this study indicate that mistletoe therapy is safe. ADRs were mostly mild to moderate in intensity and appear to be dose-related and explained by the immune-stimulating, pharmacological activity of mistletoe.
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26
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Romero-Ortuno R, O'Connell MDL, Finucane C, Soraghan C, Fan CW, Kenny RA. Insights into the clinical management of the syndrome of supine hypertension--orthostatic hypotension (SH-OH): the Irish Longitudinal Study on Ageing (TILDA). BMC Geriatr 2013; 13:73. [PMID: 23855394 PMCID: PMC3716968 DOI: 10.1186/1471-2318-13-73] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Accepted: 07/12/2013] [Indexed: 11/27/2022] Open
Abstract
Background Our previously proposed morphological classification of orthostatic hypotension (MOH) is an approach to the definition of three typical orthostatic hemodynamic patterns using non-invasive beat-to-beat monitoring. In particular, the MOH pattern of large drop/non-recovery (MOH-3) resembles the syndrome of supine hypertension–orthostatic hypotension (SH-OH), which is a treatment challenge for clinicians. The aim of this study was to characterise MOH-3 in the first wave of The Irish Longitudinal Study of Ageing (TILDA), with particular attention to concurrent symptoms of orthostatic intolerance (OI), prescribed medications and association with history of faints and blackouts. Methods The study included all TILDA wave 1 participants who had a Finometer® active stand. Automatic data signal checks were carried out to ensure that active stand data were of sufficient quality. Characterisation variables included demographics, cardiovascular and neurological medications (WHO-ATC), and self-reported information on comorbidities and disability. Multivariable statistics consisted of logistic regression models. Results Of the 4,467 cases, 1,456 (33%) were assigned to MOH-1 (small drop, overshoot), 2,230 (50%) to MOH-2 (medium drop, slower but full recovery), and 781 (18%) to MOH-3 (large drop, non-recovery). In the logistic regression model to predict MOH-3, statistically significant factors included being on antidepressants (OR = 1.99, 95% CI: 1.50 – 2.64, P < 0.001) and beta blockers (OR = 1.60, 95% CI: 1.26 – 2.04, P < 0.001). MOH-3 was an independent predictor of OI after full adjustment (OR = 1.47, 95% CI: 1.25 – 1.73, P < 0.001), together with being on hypnotics or sedatives (OR = 1.83, 95% CI: 1.31 – 2.54, P < 0.001). In addition, OI was an independent predictor of history of falls/blackouts after full adjustment (OR = 1.27, 95% CI: 1.09 – 1.48, P = 0.003). Conclusions Antidepressants and beta blockers were independently associated with MOH-3, and should be used judiciously in older patients with SH-OH. Hypnotics and sedatives may add to the OI effect of MOH-3. Several trials have demonstrated the benefits of treating older hypertensive patients with cardiovascular medications that were not associated with adverse outcomes in our study. Therefore, the evidence of benefit does not necessarily have to conflict with the evidence of potential harm.
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Affiliation(s)
- Roman Romero-Ortuno
- The Irish Longitudinal Study of Ageing (TILDA), Lincoln Gate, Trinity College Dublin, Dublin 2, Republic of Ireland.
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Peggs KJ, Nguyen H, Enayat D, Keller NR, Al-Hendy A, Raj SR. Gynecologic disorders and menstrual cycle lightheadedness in postural tachycardia syndrome. Int J Gynaecol Obstet 2012; 118:242-6. [PMID: 22721633 DOI: 10.1016/j.ijgo.2012.04.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Revised: 04/16/2012] [Accepted: 04/22/2012] [Indexed: 12/21/2022]
Abstract
OBJECTIVE To assess differences in gynecologic history and lightheadedness during menstrual cycle phases among patients with POTS and healthy control women. METHODS In a prospective, questionnaire-based study carried out at Paden Autonomic Dysfunction Center, Vanderbilt University, between April 2005 and January 2009, a custom-designed questionnaire was administered to patients with POTS (n=65) and healthy individuals (n=95). The results were analyzed via Fisher exact test and Mann-Whitney U test. RESULTS Patients with POTS reported increased lightheadedness through all phases of the menstrual cycle phases as compared with healthy controls. Both groups experienced the greatest lightheadedness during menses, and a decrease in lightheadedness during the follicular phase. Patients with POTS reported a higher incidence of gynecologic diseases as compared with healthy controls. CONCLUSION The severity of lightheadedness was found to vary during the menstrual cycle, which may relate to changes in estrogen levels. Patients with POTS also reported an increase in estrogen-related gynecologic disease.
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Affiliation(s)
- Kiffany J Peggs
- Paden Autonomic Dysfunction Service, Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, USA
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Fu Q, Vangundy TB, Galbreath MM, Shibata S, Jain M, Hastings JL, Bhella PS, Levine BD. Cardiac origins of the postural orthostatic tachycardia syndrome. J Am Coll Cardiol 2010; 55:2858-68. [PMID: 20579544 DOI: 10.1016/j.jacc.2010.02.043] [Citation(s) in RCA: 209] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 01/06/2010] [Accepted: 02/01/2010] [Indexed: 11/29/2022]
Abstract
OBJECTIVES The purpose of this study was to test the hypothesis that a small heart coupled with reduced blood volume contributes to the postural orthostatic tachycardia syndrome (POTS) and that exercise training improves this syndrome. BACKGROUND Patients with POTS have marked increases in heart rate during orthostasis. However, the underlying mechanisms are unknown and the effective therapy is uncertain. METHODS Twenty-seven POTS patients underwent autonomic function tests, cardiac magnetic resonance imaging, and blood volume measurements. Twenty-five of them participated in a 3-month specially designed exercise training program with 19 completing the program; these patients were re-evaluated after training. Results were compared with those of 16 healthy controls. RESULTS Upright heart rate and total peripheral resistance were greater, whereas stroke volume and cardiac output were smaller in patients than in controls. Baroreflex function was similar between groups. Left ventricular mass (median [25th, 75th percentiles], 1.26 g/kg [1.12, 1.37 g/kg] vs. 1.45 g/kg [1.34, 1.57 g/kg]; p < 0.01) and blood volume (60 ml/kg [54, 64 ml/kg] vs. 71 ml/kg [65, 78 ml/kg]; p < 0.01) were smaller in patients than in controls. Exercise training increased left ventricular mass and blood volume by approximately 12% and approximately 7% and decreased upright heart rate by 9 beats/min [1, 17 beats/min]. Ten of 19 patients no longer met POTS criteria after training, whereas patient quality of life assessed by the 36-item Short-Form Health Survey was improved in all patients after training. CONCLUSIONS Autonomic function was intact in POTS patients. The marked tachycardia during orthostasis was attributable to a small heart coupled with reduced blood volume. Exercise training improved or even cured this syndrome in most patients. It seems reasonable to offer POTS a new name based on its underlying pathophysiology, the "Grinch syndrome," because in this famous children's book by Dr. Seuss, the main character had a heart that was "two sizes too small."
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Affiliation(s)
- Qi Fu
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas 75231, USA
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Benjelloun H, Benjelloun H, Aboudrar S, Coghlan L, Benomar M. [Cardiovascular autonomic reflexes on the postural orthostatic tachycardia syndrome]. Ann Cardiol Angeiol (Paris) 2008; 58:20-6. [PMID: 18656847 DOI: 10.1016/j.ancard.2008.05.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2007] [Accepted: 05/18/2008] [Indexed: 11/25/2022]
Abstract
Postural orthostatic tachycardia syndrome (POTS) is an inadequately understood pathology because its diagnosis is not based on the conventional methods of investigation. The orthostatic test allows to make the diagnosis easily. The objective of this study is to determine cardiovascular autonomic reflexes of 70 patients having POTS. The tests of exploration of the autonomic nervous system practised are: deep breathing, hand grip, mental stress and orthostatic test. The analysis of orthostatic test showed that the increase of the cardiac frequency, relative to the state of "beta" peripheral sympathetic hyperactivity occurred before the 2nd minute in 80% of patients. The POTS was considered "florid" in 43% of patients and had complicated of a rough and severe fall of systolic blood pressure inferior to 70 mmHg in four patients, after the fifth minute of the test. The analysis of the different tests had shown vagal hyperactivity in 63% of patients on deep breathing, in 93% of patients on hand grip and in 100% on orthostatic test. The "alpha" central sympathetic activity was increased in 76% of the cases and "beta" central sympathetic activity was high in 83% of cases. The "alpha" peripheral hyperactivity was observed in 63% of patients on hand grip, and in 44% on orthostatic test. The analysis of cardiovascular autonomic reflexes in patients affected by POTS allowing the determination of their autonomic profile, will contribute probably to a better understanding of this pathology and to a better orientation of its care.
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Affiliation(s)
- Ho Benjelloun
- Service de cardiologie A, CHU Ibn-Sina, Rabat, Maroc.
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EDGELL HEATHER, KAUFMAN SUSAN. Effect of Hindlimb Unloading on Salt and Water Intake and Output in Male and Female Rats. Med Sci Sports Exerc 2008; 40:1249-54. [DOI: 10.1249/mss.0b013e31816a2450] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kröz M, Feder G, von Laue HB, Zerm R, Reif M, Girke M, Matthes H, Gutenbrunner C, Heckmann C. Validation of a questionnaire measuring the regulation of autonomic function. BMC COMPLEMENTARY AND ALTERNATIVE MEDICINE 2008; 8:26. [PMID: 18533043 PMCID: PMC2440731 DOI: 10.1186/1472-6882-8-26] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/12/2007] [Accepted: 06/05/2008] [Indexed: 11/10/2022]
Abstract
BACKGROUND To broaden the range of outcomes that we can measure for patients undergoing treatment for oncological and other chronic conditions, we aimed to validate a questionnaire measuring self-reported autonomic regulation (aR), i.e. to characterise a subject's autonomic functioning by questions on sleeping and waking, vertigo, morningness-eveningness, thermoregulation, perspiration, bowel movements and digestion. METHODS We administered the questionnaire to 440 participants (female symbol: N = 316, male symbol: N = 124): 95 patients with breast cancer, 49 with colorectal cancer, 60 with diabetes mellitus, 39 with coronary heart disease, 28 with rheumatological conditions, 32 with Hashimoto's disease, 22 with multiple morbidities and 115 healthy people. We administered the questionnaire a second time to 50.2% of the participants. External convergence criteria included the German version of the Hospital Anxiety and Depression Scale (HADS-D), a short questionnaire on morningness-eveningness, the Herdecke Quality of Life Questionnaire (HLQ) and a short version questionnaire on self-regulation. RESULTS A principal component analysis yielded a three dimensional 18-item inventory of aR. The subscales orthostatic-circulatory, rest/activity and digestive regulation had internal consistency (Cronbach-alpha: ralpha = 0.65 - 0.75) and test-retest reliability (rrt = 0.70 - 85). AR was negatively associated with anxiety, depression, and dysmenorrhoea but positively correlated to HLQ, self-regulation and in part to morningness (except digestive aR) (0.49 - 0.13, all p < 0.05). CONCLUSION An internal validation of the long-version scale of aR yielded consistent relationships with health versus illness, quality of life and personality. Further studies are required to clarify the issues of external validity, clinical and physiological relevance.
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Ozturk T, Kaya H, Aran G, Aksun M, Savaci S. Postoperative beneficial effects of esmolol in treated hypertensive patients undergoing laparoscopic cholecystectomy. Br J Anaesth 2008; 100:211-4. [DOI: 10.1093/bja/aem333] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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Masuki S, Eisenach JH, Schrage WG, Dietz NM, Johnson CP, Wilkins BW, Dierkhising RA, Sandroni P, Low PA, Joyner MJ. Arterial baroreflex control of heart rate during exercise in postural tachycardia syndrome. J Appl Physiol (1985) 2007; 103:1136-42. [PMID: 17673566 DOI: 10.1152/japplphysiol.00176.2007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Patients with postural tachycardia syndrome (POTS) have excessive tachycardia without hypotension during orthostasis as well as exercise. We tested the hypothesis that excessive tachycardia during exercise in POTS is not related to abnormal baroreflex control of heart rate (HR). Patients (n = 13) and healthy controls (n = 10) performed graded cycle exercise at 25, 50, and 75 W in both supine and upright positions while arterial pressure (arterial catheter) and HR (ECG) were measured. Baroreflex sensitivity of HR was assessed by bolus intravenous infusion of phenylephrine at each workload. In both positions, HR was higher in the patients than the controls during exercise. Supine baroreflex sensitivity (HR/systolic pressure) in POTS patients was -1.3 +/- 0.1 beats.min(-1).mmHg(-1) at rest and decreased to -0.6 +/- 0.1 beats.min(-1).mmHg(-1) during 75-W exercise, neither significantly different from the controls (P > 0.6). In the upright position, baroreflex sensitivity in POTS patients at rest (-1.4 +/- 0.1 beats.min(-1).mmHg(-1)) was higher than the controls (-1.0 +/- 0.1 beats.min(-1).mmHg(-1)) (P < 0.05), and it decreased to -0.1 +/- 0.04 beats.min(-1).mmHg(-1) during 75-W exercise, lower than the controls (-0.3 +/- 0.09 beats.min(-1).mmHg(-1)) (P < 0.05). The reduced arterial baroreflex sensitivity of HR during upright exercise was accompanied by greater fluctuations in systolic and pulse pressure in the patients than in the controls with 56 and 90% higher coefficient of variations, respectively (P < 0.01). However, when baroreflex control of HR was corrected for differences in HR, it was similar between the patients and controls during upright exercise. These results suggest that the tachycardia during exercise in POTS was not due to abnormal baroreflex control of HR.
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Affiliation(s)
- Shizue Masuki
- Department of Anesthesiology, Mayo Clinic and Foundation, Rochester, MN 55905, USA
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Masuki S, Eisenach JH, Schrage WG, Johnson CP, Dietz NM, Wilkins BW, Sandroni P, Low PA, Joyner MJ. Reduced stroke volume during exercise in postural tachycardia syndrome. J Appl Physiol (1985) 2007; 103:1128-35. [PMID: 17626834 DOI: 10.1152/japplphysiol.00175.2007] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Postural tachycardia syndrome (POTS) is characterized by excessive tachycardia without hypotension during orthostasis. Most POTS patients also report exercise intolerance. To assess cardiovascular regulation during exercise in POTS, patients (n = 13) and healthy controls (n = 10) performed graded cycle exercise at 25, 50, and 75 W in both supine and upright positions while arterial pressure (arterial catheter), heart rate (HR; measured by ECG), and cardiac output (open-circuit acetylene breathing) were measured. In both positions, mean arterial pressure, cardiac output, and total peripheral resistance at rest and during exercise were similar in patients and controls (P > 0.05). However, supine stroke volume (SV) tended to be lower in the patients than controls at rest (99 +/- 5 vs. 110 +/- 9 ml) and during 75-W exercise (97 +/- 5 vs. 111 +/- 7 ml) (P = 0.07), and HR was higher in the patients than controls at rest (76 +/- 3 vs. 62 +/- 4 beats/min) and during 75-W exercise (127 +/- 3 vs. 114 +/- 5 beats/min) (both P < 0.01). Upright SV was significantly lower in the patients than controls at rest (57 +/- 3 vs. 81 +/- 6 ml) and during 75-W exercise (70 +/- 4 vs. 94 +/- 6 ml) (both P < 0.01), and HR was much higher in the patients than controls at rest (103 +/- 3 vs. 81 +/- 4 beats/min) and during 75-W exercise (164 +/- 3 vs. 131 +/- 7 beats/min) (both P < 0.001). The change (upright - supine) in SV was inversely correlated with the change in HR for all participants at rest (R(2) = 0.32), at 25 W (R(2) = 0.49), 50 W (R(2) = 0.60), and 75 W (R(2) = 0.32) (P < 0.01). These results suggest that greater elevation in HR in POTS patients during exercise, especially while upright, was secondary to reduced SV and associated with exercise intolerance.
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Affiliation(s)
- Shizue Masuki
- Department of Anesthesiology, Mayo Clinic Foundation, Rochester, MN 55905, USA
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Baevsky RM, Baranov VM, Funtova II, Diedrich A, Pashenko AV, Chernikova AG, Drescher J, Jordan J, Tank J. Autonomic cardiovascular and respiratory control during prolonged spaceflights aboard the International Space Station. J Appl Physiol (1985) 2007; 103:156-61. [PMID: 17446414 DOI: 10.1152/japplphysiol.00137.2007] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Impaired autonomic control represents a cardiovascular risk factor during long-term spaceflight. Little has been reported on blood pressure (BP), heart rate (HR), and heart rate variability (HRV) during and after prolonged spaceflight. We tested the hypothesis that cardiovascular control remains stable during prolonged spaceflight. Electrocardiography, photoplethysmography, and respiratory frequency (RF) were assessed in eight male cosmonauts (age 41–50 yr, body-mass index of 22–28 kg/m2) during long-term missions (flight lengths of 162–196 days). Recordings were made 60 and 30 days before the flight, every 4 wk during flight, and on days 3 and 6 postflight during spontaneous and controlled respiration. Orthostatic testing was performed pre- and postflight. RF and BP decreased during spaceflight ( P < 0.05). Mean HR and HRV in the low- and high-frequency bands did not change during spaceflight. However, the individual responses were different and correlated with preflight values. Pulse-wave transit time decreased during spaceflight ( P < 0.05). HRV reached during controlled respiration (6 breaths/min) decreased in six and increased in one cosmonaut during flight. The most pronounced changes in HR, BP, and HRV occurred after landing. The decreases in BP and RF combined with stable HR and HRV during flight suggest functional adaptation rather than pathological changes. Pulse-wave transit time shortening in our study is surprising and may reflect cardiac output redistribution in space. The decrease in HRV during controlled respiration (6 breaths/min) indicates reduced parasympathetic reserve, which may contribute to postflight disturbances.
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Claydon VE, Younis NR, Hainsworth R. Phase of the menstrual cycle does not affect orthostatic tolerance in healthy women. Clin Auton Res 2007; 16:98-104. [PMID: 16683068 DOI: 10.1007/s10286-006-0330-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2005] [Accepted: 12/20/2005] [Indexed: 11/28/2022]
Abstract
Women of child-bearing age have a lower orthostatic tolerance (OT) than older women or men, and women suffering from frequent syncopal episodes often comment that their symptoms occur at certain times of the menstrual cycle. However, it is not known whether, in asymptomatic women, OT varies at different phases of the menstrual cycle. We studied 8 healthy asymptomatic women aged 26.8 +/- 3.4 years. We determined OT using a test of combined head-up tilting and lower body suction. We continuously monitored beat-to-beat blood pressure (Finapres), heart rate (ECG), and cerebral and forearm blood flow velocities (Doppler ultrasound). On each test day we assessed carotid baroreceptor sensitivity from suction/pressure applied to a neck chamber. We also determined estradiol and progesterone levels from a venous blood sample. Tests were performed in early follicular and late luteal phases, and during ovulation. Serum concentrations of estradiol (pmol x l(-1)) and progesterone (nmol x l(-1)) were in follicular phase 464.1 +/- 63 and 6.3 +/- 2.8; ovulation 941.6 +/- 298 and 5.8 +/- 1.2; luteal phase 698 +/- 188 and 32.3 +/- 9.6. Progesterone levels were significantly higher in the luteal phase (p < 0.001). OT was not different on any test day: follicular 31.9 +/- 1.6 min, ovulation 31.3 +/- 0.7 min; luteal 31.1 +/- 2.2 min. Supine and tilted heart rates and blood pressures, the maximum heart rate, and the cerebral autoregulatory and forearm vascular resistance responses to the orthostatic stress were similar during all studies. Both cardiac and vascular resistance carotid baroreceptor sensitivities were also similar on all test days. These results suggest that there is no difference in either OT or cardiovascular control at the tested phases of the menstrual cycle in healthy women.
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Masuki S, Eisenach JH, Johnson CP, Dietz NM, Benrud-Larson LM, Schrage WG, Curry TB, Sandroni P, Low PA, Joyner MJ. Excessive heart rate response to orthostatic stress in postural tachycardia syndrome is not caused by anxiety. J Appl Physiol (1985) 2007; 102:896-903. [PMID: 17110507 DOI: 10.1152/japplphysiol.00927.2006] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Postural tachycardia syndrome (POTS) is characterized by excessive increases in heart rate (HR) without hypotension during orthostasis. The relationship between the tachycardia and anxiety is uncertain. Therefore, we tested whether the HR response to orthostatic stress in POTS is primarily related to psychological factors. POTS patients ( n = 14) and healthy controls ( n = 10) underwent graded venous pooling with lower body negative pressure (LBNP) to −40 mmHg while wearing deflated antishock trousers. “Sham” venous pooling was performed by 1) trouser inflation to 5 mmHg during LBNP and 2) vacuum pump activation without LBNP. HR responses to mental stress were also measured in both groups, and a questionnaire was used to measure psychological parameters. During LBNP, HR in POTS patients increased 39 ± 5 beats/min vs. 19 ± 3 beats/min in control subjects at −40 mmHg ( P < 0.01). LBNP with trouser inflation markedly blunted the HR responses in the patients (9 ± 2 beats/min) and controls (2 ± 1 beats/min), and there was no HR increase during vacuum application without LBNP in either group. HR responses during mental stress were not different in the patients and controls (18 ± 2 vs. 19 ± 1 beats/min; P > 0.6). Anxiety, somatic vigilance, and catastrophic cognitions were significantly higher in the patients ( P < 0.05), but they were not related to the HR responses during LBNP or mental stress ( P > 0.1). These results suggest that the HR response to orthostatic stress in POTS patients is not caused by anxiety but that it is a physiological response that maintains arterial pressure during venous pooling.
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Affiliation(s)
- Shizue Masuki
- Dept. of Anesthesiology, Mayo Clinic and Foundation, Rochester, MN 55905, USA
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Abstract
PURPOSE OF REVIEW Postural tachycardia syndrome is an autonomic disorder primarily of younger women. The patient population is heterogeneous, making diagnosis and treatment a challenge. A mutation in the norepinephrine (noradrenaline) transporter gene prompted further genetic analysis. RECENT FINDINGS Eleven new mutations were found in the human norepinephrine transporter gene, although none were directly associated with postural tachycardia syndrome. The 5'-flanking -1012C --> T variant of the dopamine beta-hydroxylase gene was slightly increased and protection was associated with a reduced incidence of two mutations in the endothelial nitric oxide synthase gene, and one in endothelin-1. Mutations in other disease-related genes suggest a potential relationship with the pathogenesis of postural tachycardia syndrome. Benign joint hypermobility syndrome, for example, shares similar autonomic symptoms and is linked to a mutation in tenascin-X. Additional genetic findings are discussed as potential contributors to vascular health and neurodegeneration. SUMMARY Genetic testing can reveal molecular mechanisms of disease and provide an additional strategy for diagnosis and treatment of heterogeneous patient populations such as postural tachycardia syndrome. It is quite likely that the pathogenesis of this disorder will be attributed to numerous genetic mutations, both subtle and overt. Therefore, continued study of the relationships between genotype and phenotype are necessary to better understand this syndrome and others with associated dysautonomia.
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Affiliation(s)
- Nancy R Keller
- Autonomic Dysfunction Center, Division of Clinical Pharmacology, Departments of Medicine, Pharmacology and Neurology, Tennessee, USA
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Kröz M, Broder von Laue H, Zerm R, Brauer D, Reif M, Girke M, Matthes H, Heckmann C. [Reduction of endogenous regulation in internal medicine patients]. Complement Med Res 2005; 12:333-41. [PMID: 16391482 DOI: 10.1159/000089148] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND General health-related questionnaires on quality of life do not satisfactorily distinguish between healthy and sick people. One of the reasons cited for this lack is too much mental influence. This is why we developed a questionnaire on endogenous regulation (eR) that reflects the regulatory state of various vegetative functions. OBJECTIVE The current study examines whether the short version eR questionnaire is able to distinguish between healthy people and internal medicine patients. PATIENTS AND METHODS 408 participants were included in the study (284 females, 124 males). Among these were patients with colorectal cancer (n = 49), breast cancer (n = 95), diabetes mellitus (type 1: n = 20, type 2: n = 40), coronary disease (n = 39), rheumatoid illnesses (n = 28) and multimorbid patients (n = 22) as well as a healthy control group (n = 115). In addition to the eR questionnaire the study also used the Hospital Anxiety and Depression Scale (HADS), the short questionnaire on self-regulation and questions on the vegetative status. RESULTS The healthy control group showed the highest eR, with an estimated average of M = 29.8. Patients with breast cancer, diabetes mellitus type 2, coronary disease and rheumatoid illnesses reveal a significantly lowered eR. Multimorbid patients show the lowest eR. Patients with cancer of the colon and diabetes type 1 were measured at M = 27.9 and M = 27.3 respectively and showed no significantly lowered estimated average compared to the control group. A high eR significantly correlates (p < 0.002) with the following parameters: low levels of anxiety (r = 49) and depression (r = 0.36), high self-regulation (r = 0.34), morning type (r = 0.40), less congestive perspiration (r = 0.38), less shivering (r = 0.23), dysmenorrhoea (r = 0.38) and allergies (r = 0.17). CONCLUSION Healthy people show the highest, multimorbid patients the lowest eR. Consistent relations to health, illness, heat regulation and personality presence have been shown. Further studies to clarify clinical relevance are necessary.
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Affiliation(s)
- Matthias Kröz
- Forschungsinstitut Havelhöhe (FIH) am Gemeinschaftskrankenhaus Havelhöhe, Berlin, Germany.
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Tank J, Diedrich A, Szczech E, Luft FC, Jordan J. Baroreflex Regulation of Heart Rate and Sympathetic Vasomotor Tone in Women and Men. Hypertension 2005; 45:1159-64. [PMID: 15867130 DOI: 10.1161/01.hyp.0000165695.98915.9a] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Gender has been reported to influence baroreflex heart rate regulation and baroreflex blood pressure buffering. We tested the hypothesis that gender influences baroreflex regulation of heart rate and sympathetic vasomotor tone. We recruited 32 normal-weight healthy subjects (17 men and 15 women). ECGs for heart rate, brachial and finger blood pressure, and muscle sympathetic nerve activity (MSNA) were measured. Baroreflex heart rate and MSNA regulation were assessed using incremental phenylephrine and nitroprusside infusions. Baseline blood pressure was similar in men and women. MSNA was 21+/-2.5 bursts/min in women and 19+/-2.8 bursts/min in men (NS). The gain of the baroreflex MSNA curves was similar in women and men (-1.9+/-0.2 bursts/min per mm Hg in men and -2.0+/-0.3 bursts/min per mm Hg in women). Baroreflex gain for heart rate regulation was 17+/-3.2 ms/mm Hg in women and 19+/-1.9 ms/mm Hg in men (NS). We conclude that baroreflex gains for heart rate and sympathetic MSNA regulation are similar in women and men. However, the probability for congruence between men and women in terms of the MSNA baroreflex curves was 0.06% for burst rate, 0.4% for burst incidence, and 0.01% for burst area. In women, the MSNA baroreflex curve may be shifted to slightly lower blood pressure such that at a given blood pressure MSNA tends to be lower.
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Affiliation(s)
- Jens Tank
- Franz Volhard Clinical Research Center, Medical Faculty, Charité and HELIOS Klinikum, Berlin, Germany
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Meendering JR, Torgrimson BN, Houghton BL, Halliwill JR, Minson CT. Menstrual cycle and sex affect hemodynamic responses to combined orthostatic and heat stress. Am J Physiol Heart Circ Physiol 2005; 289:H631-42. [PMID: 15778279 DOI: 10.1152/ajpheart.00029.2005] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Women have decreased orthostatic tolerance compared with men, and anecdotal evidence suggests women are more susceptible to orthostatic intolerance in warm environments. Because estrogen and progesterone affect numerous physiological variables that may alter orthostatic tolerance, the purpose of our study was to compare orthostatic tolerance across the menstrual cycle phases in women during combined orthostatic and heat stress and to compare these data with those of men. Eight normally menstruating women and eight males (22 +/- 4.0 and 23 +/- 3.5 yr, respectively) completed the protocol. Women were studied during their early follicular (EF), ovulatory (OV), and midluteal (ML) phases. Men were studied twice within 2-4 wk. Heart rate, cardiac output, blood pressure, core temperature (T(c)), and cutaneous vascular conductance (CVC) were measured during three head-up tilt tests, consisting of two tilts in the thermoneutral condition and one tilt after a 0.5 degrees C rise in T(c). There was no difference in orthostatic tolerance across the menstrual cycle phases, despite higher CVC in the ML phase after heating (EF, 42.3 +/- 4.8; OV, 40.1 +/- 3.7; ML, 57.5 +/- 4.5; P < 0.05). Orthostatic tolerance in the heat was greater in men than women (P < 0.05). These data suggest that although many physiological variables associated with blood pressure regulation fluctuate during the menstrual cycle, orthostatic tolerance in the heat remains unchanged. Additionally, our data support a clear sex difference in orthostatic tolerance and extend upon previous data to show that the sex difference in the heat is not attributable to fluctuating hormone profiles during the menstrual cycle.
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Affiliation(s)
- Jessica R Meendering
- Department of Human Physiology, University of Oregon, 1240 Univ. of Oregon, Eugene, OR 97403, USA
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Davani S, Bouhaddi M, Nezelof S, Vandel S, Regnard J, Kantelip JP. Orthostatic hypotension and anorexia nervosa: is there a treatment? Therapie 2003; 58:170-2. [PMID: 12942861 DOI: 10.2515/therapie:2003027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Frishman WH, Azer V, Sica D. Drug treatment of orthostatic hypotension and vasovagal syncope. HEART DISEASE (HAGERSTOWN, MD.) 2003; 5:49-64. [PMID: 12549988 DOI: 10.1097/01.hdx.0000050416.53995.43] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Orthostatic hypotension is a common problem, estimated to occur in 5 out of every 1000 individuals and in as many as 7% to 17% of patients in an acute care setting. Moreover, orthostatic hypotension may be more prominent in elderly patients due to the increased intake of vasoactive medications and concomitant decrease in physiologic function, such as baroreceptor sensitivity, often seen with aging. Orthostatic hypotension is a fall in blood pressure on assuming an upright position. Absolute cutoffs for the drop in blood pressure are often difficult to determine because different patients exhibit varying degrees of tolerance to falls in blood pressure. Therefore, strict numerical criteria may lead to underdiagnosis and improper intervention. A thorough review of patient symptomatology combined with appropriate clinical tests should be employed to narrow the vast differential diagnosis and pinpoint the etiology. The fall in blood pressure seen in orthostatic hypotension results from the inability of the autonomic nervous system to adequately compensate for the 500 mL blood that is estimated to pool in the lower extremities on assuming an upright posture. The decrease in venous return results in a concomitant decrease in cardiac output and thus hypoperfusion of the cerebral circulation, possibly resulting in syncope or various other symptoms. A complete investigation should consider hypovolemia, removal of offending medications, primary autonomic disorders, secondary autonomic disorders and, of course, vasovagal syncope, the most common cause of syncope. Although further research is still necessary to rectify the disease process responsible for orthostatic hypotension, patients suffering from this disorder can effectively be treated through a combination of nonpharmacologic treatment, pharmacologic treatment and patient education. Agents such as fludrocortisone, midodrine and erythropoietin show promising results as therapeutic adjuncts. Treatment for recurrent vasovagal syncope includes increased salt intake, and various drug treatments, most of which are still under investigation.
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Affiliation(s)
- William H Frishman
- Department of Medicine, New York Medical College/Westchester Medical Center, Valhalla, New York 10595, USA.
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