title: Cold Exposure Can Induce an Exaggerated Early-Morning Blood Pressure Surge in Young Prehypertensives.
abstract: Prehypertension is related to a higher risk of cardiovascular events than normotension. Our previous study reported that cold exposure elevates the amplitude of the morning blood pressure surge (MBPS) and is associated with a sympathetic increase during the final sleep transition, which might be critical for sleep-related cardiovascular events in normotensives. However, few studies have explored the effects of cold exposure on autonomic function during sleep transitions and changes of autonomic function among prehypertensives. Therefore, we conducted an experiment for testing the effects of cold exposure on changes of autonomic function during sleep and the MBPS among young prehypertensives are more exaggerate than among young normotensives. The study groups consisted of 12 normotensive and 12 prehypertensive male adults with mean ages of 23.67 ± 0.70 and 25.25 ± 0.76 years, respectively. The subjects underwent cold (16°C) and warm (23°C) conditions randomly. The room temperature was maintained at either 23°C or 16°C by central air conditioning and recorded by a heat-sensitive sensor placed on the forehead and extended into the air. BP was measured every 30 minutes by using an autonomic BP monitor. Electroencephalograms, electrooculograms, electromyograms, electrocardiograms, and near body temperature were recorded by miniature polysomnography. Under cold exposure, a significantly higher amplitude of MBPS than under the warm condition among normotensives; however, this change was more exaggerated in prehypertensives. Furthermore, there was a significant decrease in parasympathetic-related RR and HF during the final sleep transition and a higher early-morning surge in BP and in LF% among prehypertensives, but no such change was found in normotensives. Our study supports that cold exposure might increase the risk of sleep-related cardiovascular events in prehypertensives.
authors.affiliation: Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan.|Sleep Research Center, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Cian-Hui
authors.initials: CH
authors.lastname: Hong
authors.affiliation: Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan.|Sleep Research Center, National Yang-Ming University, Taipei, Taiwan.|Brain Research Center, National Yang-Ming University, Taipei, Taiwan.|Department of Education and Research, Taipei City Hospital, Taipei, Taiwan.|Institute of Translational and Interdisciplinary Medicine, National Central University, Taoyuan, Taiwan.
authors.forename: Terry B J
authors.initials: TB
authors.lastname: Kuo
authors.affiliation: Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Bo-Chi
authors.initials: BC
authors.lastname: Huang
authors.affiliation: Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan.|Sleep Research Center, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Yu-Cheng
authors.initials: YC
authors.lastname: Lin
authors.affiliation: Department of Family Medicine, Taipei City Hospital, Taipei, Taiwan.
authors.forename: Kuan-Liang
authors.initials: KL
authors.lastname: Kuo
authors.affiliation: Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan.|Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Chang-Ming
authors.initials: CM
authors.lastname: Chern
authors.affiliation: Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan.|Sleep Research Center, National Yang-Ming University, Taipei, Taiwan.|Brain Research Center, National Yang-Ming University, Taipei, Taiwan.|Department of Education and Research, Taipei City Hospital, Taipei, Taiwan.
authors.forename: Cheryl C H
authors.initials: CC
authors.lastname: Yang
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory; D001831:Body Temperature; D002940:Circadian Rhythm / Q000502:physiology*; D003080:Cold Temperature / Q000009:adverse effects*; D006339:Heart Rate; D006801:Humans; D008297:Male; D008499:Medical Records; D010275:Parasympathetic Nervous System / Q000503:physiopathology; D017286:Polysomnography; D058246:Prehypertension / Q000503:physiopathology*; D012881:Skin Temperature; D012894:Sleep Stages / Q000502:physiology; D016683:Supine Position; D011795:Surveys and Questionnaires; D013564:Sympathetic Nervous System / Q000503:physiopathology; D055815:Young Adult