Obesity, Sleep Apnea, and Hypertension

Mayo Clinic, Rochester, Minn, USA.
Hypertension (Impact Factor: 6.48). 01/2004; 42(6):1067-74. DOI: 10.1161/01.HYP.0000101686.98973.A3
Source: PubMed


Obesity has a high and rising prevalence and represents a major public health problem. Obstructive sleep apnea (OSA) is also common, affecting an estimated 15 million Americans, with a prevalence that is probably also rising as a consequence of increasing obesity. Epidemiologic data support a link between obesity and hypertension as well as between OSA and hypertension. For example, untreated OSA predisposes to an increased risk of new hypertension, and treatment of OSA lowers blood pressure, even during the daytime. Possible mechanisms whereby OSA may contribute to hypertension in obese individuals include sympathetic activation, hyperleptinemia, insulin resistance, elevated angiotensin II and aldosterone levels, oxidative and inflammatory stress, endothelial dysfunction, impaired baroreflex function, and perhaps by effects on renal function. The coexistence of OSA and obesity may have more widespread implications for cardiovascular control and dysfunction in obese individuals and may contribute to some of the clustering of abnormalities broadly defined as the metabolic syndrome. From the clinical and therapeutic perspectives, the presence of resistant hypertension and the absence of a nocturnal decrease in blood pressure in obese individuals should prompt the clinician to consider the diagnosis of OSA, especially if clinical symptoms suggestive of OSA (such as poor sleep quality, witnessed apnea, excessive daytime somnolence, and so forth) are also present.

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    • "Recently, some studies suggest increased mean platelet volume as a platelet dysfunction in obstructive sleep apnea (OSA) syndrome [1] [2], which is associated with sympathetic stimulation due to hypoxic spells during sleep [3]. Apnea and hypopnea episodes in OSA are associated with increased parasympathetic activity during apnea and hypopnea and increased sympathetic activity at apnea and hypopnea termination . "
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    ABSTRACT: Some studies show increased mean platelet volume (MPV) in obstructive sleep apnea (OSA). The aim of this study was to evaluate MPV in OSA patients without cardiovascular risk factors and the possible association of heart rate derivatives with MPV. A total of 82 patients (aged 30–70 years) were divided into 2 groups according to the presence of either OSA or non-OSA as the control group. The OSA group consisted of 52 patients and the control group consisted of 30 subjects. Neither group was significantly different in terms of MPV values as well as heart rate (HR) derivatives such as minimum HR, maximum HR, the difference between maximum HR and minimum HR, mean HR, and heart rate performance index (HRPI) [(HR max. − HR min.)/HR mean] (P > 0.05 for all variables). In multivariate analysis, platelet count and percentages of recording time spent at arterial oxygen saturation < 90% significant variables are associated with MPV ( β ± SE : −0.004 ± 0.002, 95% CI, −0.008 to −0.001; P = 0.034) and ( β ± SE : 2.93 ± 1.93, 95% CI, 0.167 to 5.69; P = 0.038). Consequently, our findings predominantly suggest that there is a casual and reciprocal interaction between MPV and autonomic activation.
    Full-text · Article · Sep 2014
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    • "In another study, age was not significantly associated with the occurrence of hypertension in patients who reported a short duration of sleep.14 Obesity, especially visceral obesity, contributes to the pathogenesis of hypertension in OSA patients.15 The results from previous reports have suggested many factors that are associated with hypertension in OSA patients. "
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    ABSTRACT: Purpose Obstructive sleep apnea (OSA) is considered an independent risk factor for hypertension. However, it is still not clear which clinical factors are related with the presence of hypertension in OSA patients. We aimed to find different physical features and compare the sleep study results which are associated with the occurrence of hypertension in OSA patients. Materials and Methods Medical records were retrospectively reviewed for patients diagnosed with OSA at Severance Cardiovascular Hospital between 2010 and 2013. Males with moderate to severe OSA patients were enrolled in this study. Clinical and polysomnographic features were evaluated to assess clinical variables that are significantly associated with hypertension by statistical analysis. Results Among men with moderate to severe OSA, age was negatively correlated with hypertension (odds ratio=0.956), while neck circumference was positively correlated with the presence of hypertension (odds ratio=1.363). Among the polysomnographic results, the lowest O2 saturation during sleep was significantly associated with the presence of hypertension (odds ratio=0.900). Conclusion Age and neck circumference should be considered as clinically significant features, and the lowest blood O2 saturation during sleep should be emphasized in predicting the coexistence or development of hypertension in OSA patients.
    Full-text · Article · Sep 2014 · Yonsei Medical Journal
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    • "This disease is characterized by a loss of upper airway muscle tonus during sleep, which causes obstruction of respiratory airflow leading to hypoxia and, consequently, activation of the peripheral chemoreflex, including an increase in heart rate, arterial pressure and respiratory effort (Somers et al., 1995; Narkiewicz and Somers, 1997, 1999, 2001; Narkiewicz et al., 1998a,b; Fletcher, 2001; Usui et al., 2005; Serebrovskaya et al., 2008). OSA affects ~24% of middle aged men and 9% of middle aged women (Wolk et al., 2003b); it is strongly associated with obesity, hypertension and elevated sympathetic activity even during wakefulness (Carlson et al., 1993; Narkiewicz and Somers, 1997; Wolk and Somers, 2003; Wolk et al., 2003a,b; Spaak et al., 2005). It is believed that OSA can have a causal role in the development of hypertension (Narkiewicz and Somers, 1999). "
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    ABSTRACT: Major evolutionary trends in animal physiology have been heavily influenced by atmospheric O 2 levels. Amongst other important factors, the increase in atmospheric O 2 which occurred in the Pre-Cambrian and the development of aerobic respiration beckoned the evolution of animal organ systems that were dedicated to the absorption and transportation of O 2 , e.g., the respiratory and cardiovascular systems of vertebrates. Global variations of O 2 levels in post-Cambrian periods have also been correlated with evolutionary changes in animal physiology, especially cardiorespiratory function. Oxygen transportation systems are, in our view, ultimately controlled by the brain related mechanisms, which senses changes in O 2 availability and regulates autonomic and respiratory responses that ensure the survival of the organism in the face of hypoxic challenges. In vertebrates, the major sensorial system for oxygen sensing and responding to hypoxia is the peripheral chemoreflex neuronal pathways, which includes the oxygen chemosensitive glomus cells and several brainstem regions involved in the autonomic regulation of the cardiovascular system and respiratory control. In this review we discuss the concept that regulating O 2 homeostasis was one of the primordial roles of the nervous system. We also review the physiology of the peripheral chemoreflex, focusing on the integrative repercussions of chemoreflex activation and the evolutionary importance of this system, which is essential for the survival of complex organisms such as vertebrates. The contribution of hypoxia and peripheral chemoreflex for the development of diseases associated to the cardiovascular and respiratory systems is also discussed in an evolutionary context.
    Full-text · Article · Aug 2014 · Frontiers in Physiology
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