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The effects of body weight status on orthostatic intolerance and predisposition to noncardiac syncope
Author(s) -
Christou G.A.,
Kiortsis D.N.
Publication year - 2017
Publication title -
obesity reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.845
H-Index - 162
eISSN - 1467-789X
pISSN - 1467-7881
DOI - 10.1111/obr.12501
Subject(s) - medicine , orthostatic intolerance , orthostatic vital signs , body mass index , underweight , obesity , weight loss , population , autonomic nervous system , endocrinology , anesthesia , blood pressure , heart rate , overweight , environmental health
Summary Orthostatic intolerance (OI) is frequently the mechanism underlying the occurrence of noncardiac syncope (NCS) and is associated with substantial risk for injury. Body weight status appears to be a modifier of orthostatic responses and possibly influences the propensity to NCS. The majority of cross‐sectional studies have found that the lower the body mass index (BMI) the greater the predisposition to OI is, accompanied with both down‐regulation of sympathetic nervous system activity and up‐regulation of parasympathetic nervous system activity. These changes appear to occur across the whole spectrum of BMI values from underweight to obesity, while they may be associated more strongly with central body fat than total body fat. Weight loss following bariatric surgery has been consistently found to increase OI, attributed first to the effects of weight loss per se, second to the specific type of surgical procedure and third to the potential postoperative autonomic neuropathy due to vitamin deficiency. The increased OI following bariatric surgery renders this intervention not easily tolerable for the affected individuals, mandating increased fluid and salt intake, pharmacological measures or surgical adjustments to attenuate OI. All future studies investigating orthostatic responses and NCS should implement a matching of the population arms for BMI and ideally for body fat.