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Deng R, Victoria G, Ucci M. Associations between residential daytime indoor temperature and self-reported sleep disturbances in UK adults: A cross-sectional study. ENVIRONMENTAL RESEARCH 2024; 257:119281. [PMID: 38821464 DOI: 10.1016/j.envres.2024.119281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 04/12/2024] [Accepted: 05/29/2024] [Indexed: 06/02/2024]
Abstract
BACKGROUND In the past few decades, research on the association between indoor temperature and sleep has primarily used laboratory rather than field data collected in epidemiological cohorts. METHODS Secondary data on 2493 individuals aged 43 years was obtained from the National Survey of Health and Development (NSHD). Logistic regression models were used to investigate the associations between temperatures (indoor at home, spot measurement when the nurses visited during the day; and outdoor, monthly average) and self-reported sleep disturbances, adjusting for socio-demographics, health variables, housing variables, and temperature-related variables. RESULTS Associations were found between daytime indoor temperature with difficulty initiating (OR: 0.95, 95%CI: 0.91-0.98) and maintaining sleep (OR: 0.96, 95%CI: 0.93-0.99). Compared with neutral indoor temperatures (17-28 °C), low indoor temperature (≤17 °C) was associated with difficulty initiating sleep (OR: 1.79, 95%CI: 1.21-2.65). Stratified analysis results across tertiles showed that associations with difficulty initiating (OR: 0.87, 95%CI: 0.77-0.99) and maintaining sleep (OR: 0.88, 95%CI: 0.79-0.98) were observed respectively in the lowest (≤20 °C) and highest tertile (≥23 °C) of indoor temperature. There was no association between outdoor temperature and self-reported sleep disturbances in this study. CONCLUSION In this first UK-based epidemiology study investigating temperature and sleep, self-reported sleep disturbances were associated with residential daytime indoor temperatures. Low indoor temperature had significantly higher odds ratio for difficulty initiating sleep compared with the neutral indoor temperature. A warmer indoor environment might be more suitable for sleep maintenance than sleep initiation. Indoor temperature in this study was a superior indicator of sleep disturbances than outdoor temperature. Although these findings are based on a UK sample, they may be relevant to other high-income settings with similar housing stock and climatic conditions.
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Affiliation(s)
- Ruiwen Deng
- Institute of Environmental Design and Engineering, The Bartlett School of Environment, Energy and Resources, University College London, London, United Kingdom.
| | - Garfield Victoria
- Department of Pharmacology & Therapeutics, Institute of Systems, Molecular & Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Marcella Ucci
- Institute of Environmental Design and Engineering, The Bartlett School of Environment, Energy and Resources, University College London, London, United Kingdom
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Aijazi A, Parkinson T, Zhang H, Schiavon S. Passive and low-energy strategies to improve sleep thermal comfort and energy resilience during heat waves and cold snaps. Sci Rep 2024; 14:12568. [PMID: 38822004 PMCID: PMC11143215 DOI: 10.1038/s41598-024-62377-5] [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: 06/21/2023] [Accepted: 05/16/2024] [Indexed: 06/02/2024] Open
Abstract
Sleep is a pillar of human health and wellbeing. In high- and middle-income countries, there is a great reliance on heating, ventilation, and air conditioning systems (HVAC) to control the interior thermal environment in the bedroom. However, these systems are expensive to buy, maintain, and operate while being energy and environmentally intensive-problems that may increase due to climate change. Easily-accessible passive and low-energy strategies, such as fans and electrical heated blankets, address these challenges but their comparative effectiveness for providing comfort in sleep environments has not been studied. We used a thermal manikin to experimentally show that many passive and low-energy strategies are highly effective in supplementing or replacing HVAC systems during sleep. Using passive strategies in combination with low-energy strategies that elevate air movement like ceiling or pedestal fans enhances the cooling effect by three times compared to using fans alone. We extrapolated our experimental findings to estimate heating and cooling effects in two historical case studies: the 2015 Pakistan heat wave and the 2021 Texas power crisis. Passive and low-energy strategies reduced sleep-time heat or cold exposure by 69-91%. The low-energy strategies we tested require one to two orders of magnitude less energy than HVAC systems, and the passive strategies require no energy input. These strategies can also help reduce peak load surges and total energy demand in extreme temperature events. This reduces the need for utility load shedding, which can put individuals at risk of hazardous heat or cold exposure. Our results may serve as a starting point for evidence-based public health guidelines on how individuals can sleep better during heat waves and cold snaps without relying on HVAC.
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Affiliation(s)
- Arfa Aijazi
- Center for the Built Environment (CBE), University of California, Berkeley, CA, USA
- School of Architecture, University of Waterloo, Cambridge, ON, Canada
| | - Thomas Parkinson
- Center for the Built Environment (CBE), University of California, Berkeley, CA, USA
- Indoor Environmental Quality (IEQ) Lab, The University of Sydney, Sydney, NSW, Australia
| | - Hui Zhang
- Center for the Built Environment (CBE), University of California, Berkeley, CA, USA
| | - Stefano Schiavon
- Center for the Built Environment (CBE), University of California, Berkeley, CA, USA.
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Moyen NE, Ediger TR, Taylor KM, Hancock EG, Holden LD, Tracy EE, Kay PH, Irick CR, Kotzen KJ, He DD. Sleeping for One Week on a Temperature-Controlled Mattress Cover Improves Sleep and Cardiovascular Recovery. Bioengineering (Basel) 2024; 11:352. [PMID: 38671774 PMCID: PMC11048088 DOI: 10.3390/bioengineering11040352] [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: 02/01/2024] [Revised: 03/19/2024] [Accepted: 03/31/2024] [Indexed: 04/28/2024] Open
Abstract
Body temperature should be tightly regulated for optimal sleep. However, various extrinsic and intrinsic factors can alter body temperature during sleep. In a free-living study, we examined how sleep and cardiovascular health metrics were affected by sleeping for one week with (Pod ON) vs. without (Pod OFF), an active temperature-controlled mattress cover (the Eight Sleep Pod). A total of 54 subjects wore a home sleep test device (HST) for eight nights: four nights each with Pod ON and OFF (>300 total HST nights). Nightly sleeping heart rate (HR) and heart rate variability (HRV) were collected. Compared to Pod OFF, men and women sleeping at cooler temperatures in the first half of the night significantly improved deep (+14 min; +22% mean change; p = 0.003) and REM (+9 min; +25% mean change; p = 0.033) sleep, respectively. Men sleeping at warm temperatures in the second half of the night significantly improved light sleep (+23 min; +19% mean change; p = 0.023). Overall, sleeping HR (-2% mean change) and HRV (+7% mean change) significantly improved with Pod ON (p < 0.01). To our knowledge, this is the first study to show a continuously temperature-regulated bed surface can (1) significantly modify time spent in specific sleep stages in certain parts of the night, and (2) enhance cardiovascular recovery during sleep.
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Yan F, Zheng Q, Ke Y. Effect of quilt thermal resistance on bedding system and sleep thermal comfort. J Therm Biol 2023; 117:103713. [PMID: 37748286 DOI: 10.1016/j.jtherbio.2023.103713] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 09/08/2023] [Accepted: 09/09/2023] [Indexed: 09/27/2023]
Abstract
Ambient temperature and the bedding thermal resistance are two key factors affecting sleepers' thermal comfort. Six duvets with thermal resistance of 3.81, 5.12, 6.19, 7.81, 8.75 and 8.93 clo were included to investigate the effects of duvet thermal resistance on the sleep thermal comfort zone. Six males and six females were enrolled in a whole night sleep experiment, and the ambient temperature of the sleep room was adjusted to be thermally comfortable. Skin temperature, bed climate temperature and sleep stages were all acquired. Subjective evaluations including thermal perception and sleep quality were also assessed through questionnaires. The results indicated that increasing the thermal resistance of duvets widened the thermal comfort zone of ambient temperature, with the highest thermal resistance ranging from 8.2 to 17.7 °C and the lowest from 16.4 to 22.2 °C. The upper and lower temperature limits of the comfort zone did not significantly differ in their effect on sleep quality. The recommended bed climate temperature for comfortable sleep would be in the small range of 30-33 °C, and a good quality of sleep can be guaranteed in the scenario.
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Affiliation(s)
- Fangying Yan
- School of Textile Science and Engineering, Jiangnan University, Wuxi, China
| | - Qing Zheng
- School of Textile Science and Engineering, Jiangnan University, Wuxi, China
| | - Ying Ke
- School of Design, Jiangnan University, Wuxi, China.
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5
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Lv H, He Y, Wu J, Zhen L, Zheng Y. Chronic cold stress-induced myocardial injury: effects on oxidative stress, inflammation and pyroptosis. J Vet Sci 2022; 24:e2. [PMID: 36726274 PMCID: PMC9899938 DOI: 10.4142/jvs.22185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Revised: 09/14/2022] [Accepted: 09/21/2022] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND Hypothermia is a crucial environmental factor that elevates the risk of cardiovascular disease, but the underlying effect is unclear. OBJECTIVES This study examined the role of cold stress (CS) in cardiac injury and its underlying mechanisms. METHODS In this study, a chronic CS-induced myocardial injury model was used; mice were subjected to chronic CS (4°C) for three hours per day for three weeks. RESULTS CS could result in myocardial injury by inducing the levels of heat shock proteins 70 (HSP70), enhancing the generation of creatine phosphokinase-isoenzyme (CKMB) and malondialdehyde (MDA), increasing the contents of tumor necrosis factor-α (TNF-α), high mobility group box 1 (HMGB1) interleukin1b (IL-1β), IL-18, IL-6, and triggering the depletion of superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH). Multiple signaling pathways were activated by cold exposure, including pyroptosis-associated NOD-like receptor 3 (NLRP3)-regulated caspase-1-dependent/Gasdermin D (GSDMD), inflammation-related toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88)-mediated nuclear factor kappa B (NF-κB), and mitogen-activated protein kinase (MAPK), as well as oxidative stress-involved thioredoxin-1/thioredoxin-interacting protein (Txnip) signaling pathways, which play a pivotal role in myocardial injury resulting from hypothermia. CONCLUSIONS These findings provide new insights into the increased risk of cardiovascular disease at extremely low temperatures.
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Affiliation(s)
- Hongming Lv
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing 163319, Heilongjiang Bayi, China
| | - Yvxi He
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing 163319, Heilongjiang Bayi, China
| | - Jingjing Wu
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing 163319, Heilongjiang Bayi, China
| | - Li Zhen
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing 163319, Heilongjiang Bayi, China.
| | - Yvwei Zheng
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing 163319, Heilongjiang Bayi, China.
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6
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Xu X, Lian Z. Objective sleep assessments for healthy people in environmental research: A literature review. INDOOR AIR 2022; 32:e13034. [PMID: 35622713 DOI: 10.1111/ina.13034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 04/04/2022] [Accepted: 04/18/2022] [Indexed: 06/15/2023]
Abstract
To date, although many studies had focused on the impact of environmental factors on sleep, how to choose the proper assessment method for objective sleep quality was often ignored, especially for healthy subjects in bedroom environment. In order to provide methodological guidance for future research, this paper reviewed the assessments of objective sleep quality applied in environmental researches, compared them from the perspective of accuracy and interference, and statistically analyzed the impact of experimental type and subjects' information on method selection. The review results showed that, in contrast to polysomnography (PSG), the accuracy of actigraphy (ACT), respiratory monitoring-oxygen saturation monitoring (RM-OSM), and electrocardiograph (ECG) could reach up to 97%, 80.38%, and 79.95%, respectively. In terms of sleep staging, PSG and ECG performed the best, ACT the second, and RM-OSM the worst; as compared to single methods, mix methods were more accurate and better at sleep staging. PSG interfered with sleep a great deal, while ECG and ACT could be non-contact, and thus, the least interference with sleep was present. The type of experiment significantly influenced the choice of assessment method (p < 0.001), 85.3% of researchers chose PSG in laboratory study while 82.5% ACT in field study; moreover, PSG was often used in a relatively small number of young subjects, while ACT had a wide applicable population. In general, researchers need to pay more attention at selection of assessments in future studies, and this review can be used as a reliable reference for experimental design.
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Affiliation(s)
- Xinbo Xu
- School of Design, Shanghai Jiao Tong University, Shanghai, China
| | - Zhiwei Lian
- School of Design, Shanghai Jiao Tong University, Shanghai, China
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Chen CW, Wu CH, Liou YS, Kuo KL, Chung CH, Lin YT, Kuo TBJ, Yang CCH. Roles of cardiovascular autonomic regulation and sleep patterns in high blood pressure induced by mild cold exposure in rats. Hypertens Res 2021; 44:662-673. [PMID: 33742169 DOI: 10.1038/s41440-021-00619-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 12/08/2020] [Accepted: 12/18/2020] [Indexed: 11/09/2022]
Abstract
Increased blood pressure (BP) caused by exposure to cold temperatures can partially explain the increased incidence of cardiovascular events in winter. However, the physiological mechanisms involved in cold-induced high BP are not well established. Many studies have focused on physiological responses to severe cold exposure. In this study, we aimed to perform a comprehensive analysis of cardiovascular autonomic function and sleep patterns in rats during exposure to mild cold, a condition relevant to humans in subtropical areas, to clarify the physiological mechanisms underlying mild cold-induced hypertension. BP, electroencephalography, electromyography, electrocardiography, and core body temperature were continuously recorded in normotensive Wistar-Kyoto rats over 24 h. All rats were housed in thermoregulated chambers at ambient temperatures of 23, 18, and 15 °C in a randomized crossover design. These 24-h physiological recordings either with or without sleep scoring showed that compared with the control temperature of 23 °C, the lower ambient temperatures of 18 and 15 °C not only increased BP, vascular sympathetic activity, and heart rate but also decreased overall autonomic activity, parasympathetic activity, and baroreflex sensitivity in rats. In addition, cold exposure reduced the delta power percentage and increased the incidence of interruptions during sleep. Moreover, a correlation analysis revealed that all of these cold-induced autonomic dysregulation and sleep problems were associated with elevation of BP. In conclusion, mild cold exposure elicits autonomic dysregulation and poor sleep quality, causing BP elevation, which may have critical implications for cold-related cardiovascular events.
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Affiliation(s)
- Chieh-Wen Chen
- Sleep Research Center, National Yang-Ming University, Taipei, Taiwan
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan
| | - Cheng-Han Wu
- Sleep Research Center, National Yang-Ming University, Taipei, Taiwan
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan
| | - Yu-Syuan Liou
- Sleep Research Center, National Yang-Ming University, Taipei, Taiwan
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan
| | - Kuan-Liang Kuo
- Institute of BioMedical Informatics, National Yang-Ming University, Taipei, Taiwan
- Family Medicine Department, Taipei City Hospital, Renai Branch, Taipei, Taiwan
| | - Cheng-Hung Chung
- Sleep Research Center, National Yang-Ming University, Taipei, Taiwan
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan
| | - Yu-Ting Lin
- Sleep Research Center, National Yang-Ming University, Taipei, Taiwan
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan
| | - Terry B J Kuo
- Sleep Research Center, National Yang-Ming University, Taipei, Taiwan.
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan.
- Institute of BioMedical Informatics, 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.
| | - Cheryl C H Yang
- Sleep Research Center, National Yang-Ming University, Taipei, Taiwan.
- Institute of Brain Science, 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.
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Min KB, Lee S, Min JY. High and low ambient temperature at night and the prescription of hypnotics. Sleep 2021; 44:6016156. [PMID: 33442740 DOI: 10.1093/sleep/zsaa262] [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] [Received: 04/27/2020] [Revised: 10/04/2020] [Indexed: 11/14/2022] Open
Abstract
STUDY OBJECTIVES This study investigated the association between ambient nighttime temperature and sleep problems assessed by the prescription dose of sleeping pills in South Korean adults. METHODS We used the 2002-2015 National Health Insurance Service-National Sample Cohort. A total of 711,079 adults who were 20 years old or older were included, wherein 42,858 adults (~6%) had been prescribed hypnotic medications including zolpidem (N05CF02) and triazolam (N05CD05). Ambient temperature data was calculated as the mean highest temperature of nighttime (23:00-07:00) for every month from January to December. We combined the drug-prescribed date with the administrative districts-level daily nighttime temperature between 2002 and 2015. RESULTS We found that a non-linear, U-shaped relationship between nighttime temperature and hypnotic medication prescription. With an increase per 1°C temperature or an increase in a square per 1°C, the prescription dose of sleeping pills was significantly increased (both p < 0.05). At each 5°C nighttime temperature, subjects belonging to low (≤0°C and 0-5°C) or high (20-25°C and ≥25°C) temperature categories had significantly higher doses of sleeping pills than those at the reference temperature (10-15°C). Changes in nighttime temperature had a significant non-linear effect on the prescribed dosage of hypnotic medications for both adults (p < 0.0001) and the elderly (p = 0.0006). CONCLUSION We found that either a high or low nighttime temperature was significantly associated with a high daily dose of hypnotic medications in the Korean population.
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Affiliation(s)
- Kyoung-Bok Min
- Department of Preventive Medicine, College of Medicine, Seoul National University, Seoul, Republic of Korea
| | - Sohyae Lee
- Department of Preventive Medicine, College of Medicine, Seoul National University, Seoul, Republic of Korea
| | - Jin-Young Min
- Veterans Medical Research Institute, Veterans Health Service Medical Center, Seoul, Republic of Korea
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Mejía-Mejía E, Budidha K, Abay TY, May JM, Kyriacou PA. Heart Rate Variability (HRV) and Pulse Rate Variability (PRV) for the Assessment of Autonomic Responses. Front Physiol 2020; 11:779. [PMID: 32792970 PMCID: PMC7390908 DOI: 10.3389/fphys.2020.00779] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 06/15/2020] [Indexed: 12/29/2022] Open
Abstract
Introduction: Heart Rate Variability (HRV) and Pulse Rate Variability (PRV), are non-invasive techniques for monitoring changes in the cardiac cycle. Both techniques have been used for assessing the autonomic activity. Although highly correlated in healthy subjects, differences in HRV and PRV have been observed under various physiological conditions. The reasons for their disparities in assessing the degree of autonomic activity remains unknown. Methods: To investigate the differences between HRV and PRV, a whole-body cold exposure (CE) study was conducted on 20 healthy volunteers (11 male and 9 female, 30.3 ± 10.4 years old), where PRV indices were measured from red photoplethysmography signals acquired from central (ear canal, ear lobe) and peripheral sites (finger and toe), and HRV indices from the ECG signal. PRV and HRV indices were used to assess the effects of CE upon the autonomic control in peripheral and core vasculature, and on the relationship between HRV and PRV. The hypotheses underlying the experiment were that PRV from central vasculature is less affected by CE than PRV from the peripheries, and that PRV from peripheral and central vasculature differ with HRV to a different extent, especially during CE. Results: Most of the PRV time-domain and Poincaré plot indices increased during cold exposure. Frequency-domain parameters also showed differences except for relative-power frequency-domain parameters, which remained unchanged. HRV-derived parameters showed a similar behavior but were less affected than PRV. When PRV and HRV parameters were compared, time-domain, absolute-power frequency-domain, and non-linear indices showed differences among stages from most of the locations. Bland-Altman analysis showed that the relationship between HRV and PRV was affected by CE, and that it recovered faster in the core vasculature after CE. Conclusion: PRV responds to cold exposure differently to HRV, especially in peripheral sites such as the finger and the toe, and may have different information not available in HRV due to its non-localized nature. Hence, multi-site PRV shows promise for assessing the autonomic activity on different body locations and under different circumstances, which could allow for further understanding of the localized responses of the autonomic nervous system.
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Affiliation(s)
- Elisa Mejía-Mejía
- Research Centre for Biomedical Engineering (RCBE), School of Mathematics, Engineering and Computer Science, University of London, London, United Kingdom
| | - Karthik Budidha
- Research Centre for Biomedical Engineering (RCBE), School of Mathematics, Engineering and Computer Science, University of London, London, United Kingdom
| | - Tomas Ysehak Abay
- Research Centre for Biomedical Engineering (RCBE), School of Mathematics, Engineering and Computer Science, University of London, London, United Kingdom
| | - James M May
- Research Centre for Biomedical Engineering (RCBE), School of Mathematics, Engineering and Computer Science, University of London, London, United Kingdom
| | - Panayiotis A Kyriacou
- Research Centre for Biomedical Engineering (RCBE), School of Mathematics, Engineering and Computer Science, University of London, London, United Kingdom
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10
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The Effects of Low Air Temperatures on Thermoregulation and Sleep of Young Men While Sleeping Using Bedding. BUILDINGS 2018. [DOI: 10.3390/buildings8060076] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Cong P, Liu Y, Liu N, Zhang Y, Tong C, Shi L, Liu X, Shi X, Liu Y, Tong Z, Hou M. Cold exposure induced oxidative stress and apoptosis in the myocardium by inhibiting the Nrf2-Keap1 signaling pathway. BMC Cardiovasc Disord 2018; 18:36. [PMID: 29448942 PMCID: PMC5815212 DOI: 10.1186/s12872-018-0748-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 01/17/2018] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Exposure to cold weather is associated with infaust cardiovascular responses, including myocardial infarction and arrhythmias. However, the exact mechanisms of these adverse changes in the myocardium under cold stress are unknown. This study was designed to investigate the mechanisms of cardiac injury induced by cold stress in mice. METHODS The mice were randomly divided into three groups, normal control (no handling), 1-week cold stress and 2-week cold stress. We observed physiological changes of the mice and morphological changes of myocardium tissues, and we measured the changes of 3'-nitrotyrosine and 4-hydroxynonenal, the expression levels of superoxide dismutase-1, superoxide dismutase-2, Bax, Bad, Bcl-2, Nuclear factor erythroid-derived 2-like 2 (Nrf2) and Kelch like-ECH-associated protein 1 (Keap1) in myocardium by western blot. Besides, we detected mRNA of superoxide dismutase-1, superoxide dismutase-2, Bax, Bad, Bcl-2, Nrf2 and Keap1 by real-time PCR. One-way analysis of variance, followed by LSD-t test, was used to compare each variable for differences among the groups. RESULTS Echocardiography analyses demonstrated left ventricle dysfunction in the groups receiving cold stress. Histological analyses witnessed inflammation, vacuolar and eosinophilic degeneration occurred in left ventricle tissues. Western blotting results showed increased 3'-nitrotyrosine and 4-hydroxynonenal and decreased antioxidant enzymes (superoxide dismutase-1 and superoxide dismutase-2) in the myocardium. Expression of Nrf2 and Keap1 followed a downward trend under cold exposure, as indicated by western blotting and real-time PCR. Expression of anti-apoptotic protein Bcl-2 also showed the same trend. In contrast, expression of pro-apoptotic proteins Bax and Bad followed an upward trend under cold exposure. The results of real-time PCR were consistent with those of western blotting. CONCLUSIONS These findings were very significant, showing that cold exposure induced cardiac injury by inhibiting the Nrf2-Keap1 signaling pathway.
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Affiliation(s)
- Peifang Cong
- Emergency Medicine Department of General Hospital of Shenyang Military Command, Laboratory of Rescue Center of Severe Wound and Trauma PLA, No. 83 Road, Shenhe District, Shenyang, l10016, China
| | - Yunen Liu
- Emergency Medicine Department of General Hospital of Shenyang Military Command, Laboratory of Rescue Center of Severe Wound and Trauma PLA, No. 83 Road, Shenhe District, Shenyang, l10016, China
| | - Nannan Liu
- Emergency Medicine Department of General Hospital of Shenyang Military Command, Laboratory of Rescue Center of Severe Wound and Trauma PLA, No. 83 Road, Shenhe District, Shenyang, l10016, China
| | - Yubiao Zhang
- Emergency Medicine Department of General Hospital of Shenyang Military Command, Laboratory of Rescue Center of Severe Wound and Trauma PLA, No. 83 Road, Shenhe District, Shenyang, l10016, China
| | - Changci Tong
- Emergency Medicine Department of General Hospital of Shenyang Military Command, Laboratory of Rescue Center of Severe Wound and Trauma PLA, No. 83 Road, Shenhe District, Shenyang, l10016, China
| | - Lin Shi
- Emergency Medicine Department of General Hospital of Shenyang Military Command, Laboratory of Rescue Center of Severe Wound and Trauma PLA, No. 83 Road, Shenhe District, Shenyang, l10016, China
| | - Xuelei Liu
- Emergency Medicine Department of General Hospital of Shenyang Military Command, Laboratory of Rescue Center of Severe Wound and Trauma PLA, No. 83 Road, Shenhe District, Shenyang, l10016, China
| | - Xiuyun Shi
- Emergency Medicine Department of General Hospital of Shenyang Military Command, Laboratory of Rescue Center of Severe Wound and Trauma PLA, No. 83 Road, Shenhe District, Shenyang, l10016, China
| | - Ying Liu
- Emergency Medicine Department of General Hospital of Shenyang Military Command, Laboratory of Rescue Center of Severe Wound and Trauma PLA, No. 83 Road, Shenhe District, Shenyang, l10016, China
| | - Zhou Tong
- Emergency Medicine Department of General Hospital of Shenyang Military Command, Laboratory of Rescue Center of Severe Wound and Trauma PLA, No. 83 Road, Shenhe District, Shenyang, l10016, China
| | - Mingxiao Hou
- Emergency Medicine Department of General Hospital of Shenyang Military Command, Laboratory of Rescue Center of Severe Wound and Trauma PLA, No. 83 Road, Shenhe District, Shenyang, l10016, China.
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12
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Shin M, Halaki M, Swan P, Ireland AH, Chow CM. The effects of fabric for sleepwear and bedding on sleep at ambient temperatures of 17°C and 22°C. Nat Sci Sleep 2016; 8:121-31. [PMID: 27217803 PMCID: PMC4853167 DOI: 10.2147/nss.s100271] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The fibers used in clothing and bedding have different thermal properties. This study aimed to investigate the influences of textile fabrics on sleep under different ambient temperature (T a) conditions. Seventeen healthy young participants (ten males) underwent nine nights of polysomnography testing including an adaptation night. Participants were randomized to each of the three binary factors: sleepwear (cotton vs wool), bedding (polyester vs wool), and T a (17°C vs 22°C with relative humidity set at 60%). Skin temperature (T sk) and core temperature (T c) were monitored throughout the sleep period. Sleep onset latency (SOL) was significantly shortened when sleeping in wool with trends of increased total sleep time and sleep efficiency compared to cotton sleepwear. At 17°C, the proportion of sleep stages 1 (%N1) and 3 (%N3) and rapid eye movement sleep was higher, but %N2 was lower than at 22°C. Interaction effects (sleepwear × T a) showed a significantly shorter SOL for wool than cotton at 17°C but lower %N3 for wool than cotton at 22°C. A significantly lower %N2 but higher %N3 was observed for wool at 17°C than at 22°C. There was no bedding effect on sleep. Several temperature variables predicted the sleep findings in a stepwise multiple regression analysis and explained 67.8% of the variance in SOL and to a lesser degree the %N2 and %N3. These findings suggest that sleepwear played a contributory role to sleep outcomes and participants slept better at 17°C than at 22°C.
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Affiliation(s)
- Mirim Shin
- Exercise, Health and Performance Research Group, Faculty of Health Sciences, The University of Sydney, Lidcombe, Australia
| | - Mark Halaki
- Exercise, Health and Performance Research Group, Faculty of Health Sciences, The University of Sydney, Lidcombe, Australia
| | - Paul Swan
- Australian Wool Innovation Limited, The Woolmark Company, Sydney, NSW, Australia
| | - Angus H Ireland
- Australian Wool Innovation Limited, The Woolmark Company, Sydney, NSW, Australia
| | - Chin Moi Chow
- Exercise, Health and Performance Research Group, Faculty of Health Sciences, The University of Sydney, Lidcombe, Australia
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13
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Liu C, Yavar Z, Sun Q. Cardiovascular response to thermoregulatory challenges. Am J Physiol Heart Circ Physiol 2015; 309:H1793-812. [PMID: 26432837 DOI: 10.1152/ajpheart.00199.2015] [Citation(s) in RCA: 170] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 09/28/2015] [Indexed: 01/05/2023]
Abstract
A growing number of extreme climate events are occurring in the setting of ongoing climate change, with an increase in both the intensity and frequency. It has been shown that ambient temperature challenges have a direct and highly varied impact on cardiovascular health. With a rapidly growing amount of literature on this issue, we aim to review the recent publications regarding the impact of cold and heat on human populations with regard to cardiovascular disease (CVD) mortality/morbidity while also examining lag effects, vulnerable subgroups, and relevant mechanisms. Although the relative risk of morbidity/mortality associated with extreme temperature varied greatly across different studies, both cold and hot temperatures were associated with a positive mean excess of cardiovascular deaths or hospital admissions. Cause-specific study of CVD morbidity/mortality indicated that the sensitivity to temperature was disease-specific, with different patterns for acute and chronic ischemic heart disease. Vulnerability to temperature-related mortality was associated with some characteristics of the populations, including sex, age, location, socioeconomic condition, and comorbidities such as cardiac diseases, kidney diseases, diabetes, and hypertension. Temperature-induced damage is thought to be related to enhanced sympathetic reactivity followed by activation of the sympathetic nervous system, renin-angiotensin system, as well as dehydration and a systemic inflammatory response. Future research should focus on multidisciplinary adaptation strategies that incorporate epidemiology, climatology, indoor/building environments, energy usage, labor legislative perfection, and human thermal comfort models. Studies on the underlying mechanism by which temperature challenge induces pathophysiological response and CVD await profound and lasting investigation.
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Affiliation(s)
- Cuiqing Liu
- Basic Medical College, Zhejiang Chinese Medical University, Hangzhou, China; and
| | - Zubin Yavar
- Division of Environmental Health Sciences, College of Public Health, The Ohio State University, Columbus, Ohio
| | - Qinghua Sun
- Division of Environmental Health Sciences, College of Public Health, The Ohio State University, Columbus, Ohio
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14
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Huang WL, Hwang BT, Lai CT, Li JY, Kuo TBJ, Yang CCH. Is Heart Rate Variability Related to Season of Birth? Clin Cardiol 2015. [PMID: 26212374 DOI: 10.1002/clc.22410] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Season of birth (SOB) has been found to be related to cardiovascular mortality, but the mechanisms are unclear. It is suggested that birth in winter is a protective factor for the circulatory system, and this should be able to be observed using heart rate variability (HRV) measurements. The phenomenon may have a sex difference and is likely to be modulated by climatic factors. This study focused on this problem and investigates healthy school-age children to minimize confounding factors. HYPOTHESIS Birth in winter is protective to cardiovascular system via autonomic modulation. There is a gender difference in the relationship between SOB and autonomic activity. Climatic factors are the cause of SOB effects on autonomic system. METHODS A total of 381 healthy school-age children were recruited for this study. Their HRV profiles were measured once and climatic information related to their month of birth was gathered. The HRV profiles of the 2 sexes and 4 seasons of birth were compared. Correlation and regression analysis were performed to clarify the relationship between climatic factors and the HRV results. RESULTS Boys born in winter have higher high-frequency power (HF) but a lower ratio of low-frequency power to high-frequency power (LF/HF) than do males born in other seasons. This result is not found for girls. Age and the temperature of the SOB are predictive factors for HF among boys. The humidity of SOB is a predictive factor for normalized low-frequency power (LF%) and LF/HF among girls. CONCLUSIONS Season of birth is related to both parasympathetic and sympathetic activity among school-age children, especially boys. Temperature and humidity are potential causes of this SOB phenomenon.
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Affiliation(s)
- Wei-Lieh Huang
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan.,Department of Psychiatry, National Taiwan University Hospital, Yun-Lin Branch, Yunlin, Taiwan.,Department of Psychiatry, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Be-Tau Hwang
- Department of Pediatrics, Taipei City Hospital, Taipei, Taiwan
| | - Chun-Ting Lai
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan.,Sleep Research Center, National Yang-Ming University, Taipei, Taiwan
| | - Jia-Yi Li
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan.,Sleep Research Center, National Yang-Ming University, Taipei, Taiwan
| | - Terry B J Kuo
- 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
| | - Cheryl C H Yang
- 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
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15
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Koenig J, Jarczok MN, Wasner M, Hillecke TK, Thayer JF. Heart rate variability and swimming. Sports Med 2015; 44:1377-91. [PMID: 24958562 DOI: 10.1007/s40279-014-0211-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
BACKGROUND AND OBJECTIVES Professionals in the domain of swimming have a strong interest in implementing research methods in evaluating and improving training methods to maximize athletic performance and competitive outcome. Heart rate variability (HRV) has gained attention in research on sport and exercise to assess autonomic nervous system activity underlying physical activity and sports performance. Studies on swimming and HRV are rare. This review aims to summarize the current evidence on the application of HRV in swimming research and draws implications for future research. METHODS A systematic search of databases (PubMed via MEDLINE, PSYNDEX and Embase) according to the PRISMA statement was employed. Studies were screened for eligibility on inclusion criteria: (a) empirical investigation (HRV) in humans (non-clinical); (b) related to swimming; (c) peer-reviewed journal; and (d) English language. RESULTS The search revealed 194 studies (duplicates removed), of which the abstract was screened for eligibility. Fourteen studies meeting the inclusion criteria were included in the review. Included studies broadly fell into three classes: (1) control group designs to investigate between-subject differences (i.e. swimmers vs. non-swimmers, swimmers vs. other athletes); (2) repeated measures designs on within-subject differences of interventional studies measuring HRV to address different modalities of training or recovery; and (3) other studies, on the agreement of HRV with other measures. CONCLUSIONS The feasibility and possibilities of HRV within this particular field of application are well documented within the existing literature. Future studies, focusing on translational approaches that transfer current evidence in general practice (i.e. training of athletes) are needed.
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Affiliation(s)
- Julian Koenig
- Department of Psychology, The Ohio State University, Columbus, OH, USA,
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16
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Mehta AJ, Kloog I, Zanobetti A, Coull BA, Sparrow D, Vokonas P, Schwartz J. Associations between changes in city and address specific temperature and QT interval--the VA Normative Aging Study. PLoS One 2014; 9:e106258. [PMID: 25238150 PMCID: PMC4169528 DOI: 10.1371/journal.pone.0106258] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 08/04/2014] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND The underlying mechanisms of the association between ambient temperature and cardiovascular morbidity and mortality are not well understood, particularly for daily temperature variability. We evaluated if daily mean temperature and standard deviation of temperature was associated with heart rate-corrected QT interval (QTc) duration, a marker of ventricular repolarization in a prospective cohort of older men. METHODS This longitudinal analysis included 487 older men participating in the VA Normative Aging Study with up to three visits between 2000-2008 (n = 743). We analyzed associations between QTc and moving averages (1-7, 14, 21, and 28 days) of the 24-hour mean and standard deviation of temperature as measured from a local weather monitor, and the 24-hour mean temperature estimated from a spatiotemporal prediction model, in time-varying linear mixed-effect regression. Effect modification by season, diabetes, coronary heart disease, obesity, and age was also evaluated. RESULTS Higher mean temperature as measured from the local monitor, and estimated from the prediction model, was associated with longer QTc at moving averages of 21 and 28 days. Increased 24-hr standard deviation of temperature was associated with longer QTc at moving averages from 4 and up to 28 days; a 1.9°C interquartile range increase in 4-day moving average standard deviation of temperature was associated with a 2.8 msec (95%CI: 0.4, 5.2) longer QTc. Associations between 24-hr standard deviation of temperature and QTc were stronger in colder months, and in participants with diabetes and coronary heart disease. CONCLUSION/SIGNIFICANCE In this sample of older men, elevated mean temperature was associated with longer QTc, and increased variability of temperature was associated with longer QTc, particularly during colder months and among individuals with diabetes and coronary heart disease. These findings may offer insight of an important underlying mechanism of temperature-related cardiovascular morbidity and mortality in an older population.
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Affiliation(s)
- Amar J. Mehta
- Exposure, Epidemiology and Risk Program, Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - Itai Kloog
- Exposure, Epidemiology and Risk Program, Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, United States of America
- The Department of Geography and Environmental Development, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Antonella Zanobetti
- Exposure, Epidemiology and Risk Program, Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - Brent A. Coull
- Department of Biostatistics, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - David Sparrow
- The VA Normative Aging Study, Veterans Affairs Boston Healthcare System, Boston, Massachusetts, United States of America
- The Channing Laboratory, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Pantel Vokonas
- The VA Normative Aging Study, Veterans Affairs Boston Healthcare System, Boston, Massachusetts, United States of America
- Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Joel Schwartz
- Exposure, Epidemiology and Risk Program, Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, United States of America
- The Channing Laboratory, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
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17
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Wasserman EB, Zareba W, Utell MJ, Oakes D, Hopke PK, Frampton M, Chalupa D, Beckett W, Rich DQ. Acute Changes in Ambient Temperature Are Associated With Adverse Changes in Cardiac Rhythm. AIR QUALITY, ATMOSPHERE, & HEALTH 2014; 7:357-367. [PMID: 25368681 PMCID: PMC4215641 DOI: 10.1007/s11869-014-0244-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
BACKGROUND Both increases and decreases in ambient temperature have been associated with increased cardiovascular mortality and morbidity. However, the mechanism(s) remain unclear. OBJECTIVES We examined associations between biomarkers of pathways thought to, in part, explain these associations and changes in ambient temperature in a panel of predominantly post-myocardial infarction or post-stent patients. METHODS We studied 76 subjects who had a recent coronary event and were participating in a cardiac rehabilitation program. In these patients, we measured heart rate variability, repolarization, and baroreflex sensitivity parameters using Holter ECG recordings before and during supervised, graded, twice weekly, exercise sessions. Hourly temperature measurements were made at a monitoring site near the rehabilitation center. RESULTS Using linear mixed models, we observed decreases in rMSSD (square root of the mean of the sum of the squared differences between adjacent NN intervals) and deceleration capacity, associated with increases in ambient temperature in the previous four days. Additionally, decreased rMSSD was associated with both increasing temperature (mean in previous 6 hours) in the summer and decreasing temperature (mean in the previous 3 weeks) in the winter. CONCLUSIONS In a panel of cardiac rehabilitation patients, changes in ambient temperature were associated with decreases in markers of heart rate variability and baroreflex sensitivity, which may lead to increased risk of arrhythmic events and sudden death in post-infarction patients.
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Affiliation(s)
- Erin B. Wasserman
- Department of Public Health Sciences, University of Rochester School of Medicine and Dentistry, 265 Crittenden Boulevard, CU420644, Rochester, NY 14642
| | - Wojciech Zareba
- Division of Cardiology, Department of Medicine, University of Rochester School of Medicine and Dentistry, 265 Crittenden Boulevard, Rochester, NY 14642
| | - Mark J. Utell
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Box 692, Rochester, NY 14642
| | - David Oakes
- Department of Biostatistics and Computational Biology, University of Rochester School of Medicine and Dentistry, 601 Elmwood Ave, Box 630, Rochester, NY 14642
| | - Philip K. Hopke
- Department of Chemical and Biomolecular Engineering, Clarkson University, PO Box 5708, Potsdam, NY 13699-5708
| | - Mark Frampton
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Box 692, Rochester, NY 14642
| | - David Chalupa
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Box 692, Rochester, NY 14642
| | - William Beckett
- Department of Medicine, Mount Auburn Hospital, 330 Mount Auburn Street, Cambridge, MA 02138
| | - David Q. Rich
- Department of Public Health Sciences, University of Rochester School of Medicine and Dentistry, 265 Crittenden Boulevard, CU420644, Rochester, NY 14642
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18
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Kuo TBJ, Hong CH, Hsieh IT, Lee GS, Yang CCH. Effects of cold exposure on autonomic changes during the last rapid eye movement sleep transition and morning blood pressure surge in humans. Sleep Med 2014; 15:986-97. [PMID: 25011661 DOI: 10.1016/j.sleep.2014.03.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Revised: 02/24/2014] [Accepted: 03/19/2014] [Indexed: 11/30/2022]
Abstract
BACKGROUND Various studies have linked the occurrence of cardiovascular events and low ambient temperatures as well as the morning blood pressure surge (MBPS). We hypothesized that low ambient temperatures produce a higher sympathetic change during the last rapid eye movement (REM) sleep transition and that this may play an important role in cold-related cardiovascular events. METHODS All experiments were carried out on 12 healthy male adults, aged 24.00±0.74 years, who participated in two experimental conditions randomly (>1 day apart): warm (23 °C) and cold (16°C). Blood pressure (BP) was measured every 30 min for 24 h by autonomic ambulatory BP monitoring. The electroencephalograms, electrocardiograms, ambient temperature, near-body temperature, and physical activity were recorded by miniature polysomnography for 24 h. RESULTS The cold conditions resulted in: (i) higher MBPS than under warm conditions; (ii) significant and greater sympathetic index changes during the sleep-wake transition than during cover-to-uncover and supine-to-sit position tests; (iii) the non-REM-REM transition-related sympathetic elevation during the cold conditions being significantly higher in late sleep period than in early sleep period; (iv) at 1h prior to morning awakening, the value of total power of heart rate variability changes being significantly negatively correlated with the changes of near-body temperature; and (v) significantly higher arousal index and shorter average interval of REM periods than in warm conditions. CONCLUSION Cold exposure elevates the amplitude of MBPS and is associated with late sleep stage transition sympathetic activation, which might have important implications for cold-related cardiovascular events.
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Affiliation(s)
- Terry B J Kuo
- Sleep Research Center, School of Medicine, National Yang-Ming University, Taipei, Taiwan; Institute of Brain Science, School of Medicine, National Yang-Ming University, Taipei, Taiwan; Institute of Biophotonics, School of Medicine, National Yang-Ming University, Taipei, Taiwan; Department of Education and Research, Taipei City Hospital, Taipei, Taiwan
| | - Cian-Hui Hong
- Sleep Research Center, School of Medicine, National Yang-Ming University, Taipei, Taiwan; Institute of Brain Science, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - I-Te Hsieh
- Sleep Research Center, School of Medicine, National Yang-Ming University, Taipei, Taiwan; Institute of Brain Science, School of Medicine, National Yang-Ming University, Taipei, Taiwan; Institute of Biophotonics, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Guo-She Lee
- Institute of Brain Science, School of Medicine, National Yang-Ming University, Taipei, Taiwan; Faculty of Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan; Department of Education and Research, Taipei City Hospital, Taipei, Taiwan
| | - Cheryl C H Yang
- Sleep Research Center, School of Medicine, National Yang-Ming University, Taipei, Taiwan; Institute of Brain Science, School of Medicine, National Yang-Ming University, Taipei, Taiwan; Department of Education and Research, Taipei City Hospital, Taipei, Taiwan.
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19
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Lim YH, Kim H, Kim JH, Bae S, Hong YC. Effect of diurnal temperature range on cardiovascular markers in the elderly in Seoul, Korea. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2013; 57:597-603. [PMID: 22956153 DOI: 10.1007/s00484-012-0587-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Revised: 08/13/2012] [Accepted: 08/14/2012] [Indexed: 06/01/2023]
Abstract
While diurnal temperature range (DTR) has been found to be a risk factor for mortality, evaluation of the underlying mechanisms involved in this association are lacking. To explain the association between DTR and health effects, we investigated how cardiovascular markers responded to DTR. Data was obtained from 560 participants who regularly attended a community elderly welfare center located in Seoul, Korea. Data collection was conducted a total of five times over a 3-year period beginning in August, 2008. We examined systolic and diastolic blood pressure (BP), heart rate (HR), and heart rate variability (HRV). Mixed-effects models and generalized additive mixed models were used to assess the relationship of DTR with BP, HR, and HRV. BP was not associated significantly with rapid temperature changes during the day. While HR was associated linearly with increments of DTR, the relationship between DTR and HRV showed nonlinear associations, or the presence of a cutoff around median DTR. At the cutoff level of DTR determined by an inflection point in the graph, standard deviation of normal-to-normal intervals (SDNN) and root mean square successive difference (RMSSD) were peaked, whereas the low frequency:high frequency (LF:HF) ratio was elevated with decreasing DTR below the cutoff level. The study demonstrated that HR increases with increasing temperature range during the day, and that HRV is reduced at small or large DTR, which suggests minimal cardiovascular stress around the median level of temperature range during the day.
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Affiliation(s)
- Youn-Hee Lim
- Department of Epidemiology and Biostatistics, Graduate School of Public Health, Seoul National University, Seoul, Republic of Korea
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20
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Okamoto-Mizuno K, Mizuno K. Effects of thermal environment on sleep and circadian rhythm. J Physiol Anthropol 2012; 31:14. [PMID: 22738673 PMCID: PMC3427038 DOI: 10.1186/1880-6805-31-14] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Accepted: 05/31/2012] [Indexed: 01/04/2023] Open
Abstract
The thermal environment is one of the most important factors that can affect human sleep. The stereotypical effects of heat or cold exposure are increased wakefulness and decreased rapid eye movement sleep and slow wave sleep. These effects of the thermal environment on sleep stages are strongly linked to thermoregulation, which affects the mechanism regulating sleep. The effects on sleep stages also differ depending on the use of bedding and/or clothing. In semi-nude subjects, sleep stages are more affected by cold exposure than heat exposure. In real-life situations where bedding and clothing are used, heat exposure increases wakefulness and decreases slow wave sleep and rapid eye movement sleep. Humid heat exposure further increases thermal load during sleep and affects sleep stages and thermoregulation. On the other hand, cold exposure does not affect sleep stages, though the use of beddings and clothing during sleep is critical in supporting thermoregulation and sleep in cold exposure. However, cold exposure affects cardiac autonomic response during sleep without affecting sleep stages and subjective sensations. These results indicate that the impact of cold exposure may be greater than that of heat exposure in real-life situations; thus, further studies are warranted that consider the effect of cold exposure on sleep and other physiological parameters.
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Affiliation(s)
- Kazue Okamoto-Mizuno
- Kansei Fukushi Research Center, Tohoku Fukushi University, 1-149-6 Kunimigaoka Aoba Sendai, Miyagi, 981-0935, Japan.
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21
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Zhang Y, Li L, Hua Y, Nunn JM, Dong F, Yanagisawa M, Ren J. Cardiac-specific knockout of ET(A) receptor mitigates low ambient temperature-induced cardiac hypertrophy and contractile dysfunction. J Mol Cell Biol 2012; 4:97-107. [PMID: 22442497 DOI: 10.1093/jmcb/mjs002] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Cold exposure is associated with oxidative stress and cardiac dysfunction. The endothelin (ET) system, which plays a key role in myocardial homeostasis, may participate in cold exposure-induced cardiovascular dysfunction. This study was designed to examine the role of ET-1 in cold stress-induced cardiac geometric and contractile responses. Wild-type (WT) and ET(A) receptor knockout (ETAKO) mice were assigned to normal or cold exposure (4°C) environment for 2 and 5 weeks prior to evaluation of cardiac geometry, contractile, and intracellular Ca(2+) properties. Levels of the temperature sensor transient receptor potential vanilloid (TRPV1), mitochondrial proteins for biogenesis and oxidative phosphorylation, including UCP2, HSP90, and PGC1α were evaluated. Cold stress triggered cardiac hypertrophy, depressed myocardial contractile capacity, including fractional shortening, peak shortening, and maximal velocity of shortening/relengthening, reduced intracellular Ca(2+) release, prolonged intracellular Ca(2+) decay and relengthening duration, generation of ROS and superoxide, as well as apoptosis, the effects of which were blunted by ETAKO. Western blotting revealed downregulated TRPV1 and PGC1α as well as upregulated UCP2 and activation of GSK3β, GATA4, and CREB in cold-stressed WT mouse hearts, which were obliterated by ETAKO. Levels of HSP90, an essential regulator for thermotolerance, were unchanged. The TRPV1 agonist SA13353 attenuated whereas TRPV1 antagonist capsazepine mimicked cold stress- or ET-1-induced cardiac anomalies. The GSK3β inhibitor SB216763 ablated cold stress-induced cardiac contractile (but not remodeling) changes and ET-1-induced TRPV1 downregulation. These data suggest that ETAKO protects against cold exposure-induced cardiac remodeling and dysfunction mediated through TRPV1 and mitochondrial function.
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Affiliation(s)
- Yingmei Zhang
- Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China
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Ren C, O'Neill MS, Park SK, Sparrow D, Vokonas P, Schwartz J. Ambient temperature, air pollution, and heart rate variability in an aging population. Am J Epidemiol 2011; 173:1013-21. [PMID: 21385834 DOI: 10.1093/aje/kwq477] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Studies show that ambient temperature and air pollution are associated with cardiovascular disease and that they may interact to affect cardiovascular events. However, few epidemiologic studies have examined mechanisms through which ambient temperature may influence cardiovascular function. The authors examined whether temperature was associated with heart rate variability (HRV) in a Boston, Massachusetts, study population and whether such associations were modified by ambient air pollution concentrations. The population was a cohort of 694 older men examined between 2000 and 2008. The authors fitted a mixed model to examine associations between temperature and air pollution and their interactions with repeated HRV measurements, adjusting for covariates selected a priori on the basis of their previous studies. Results showed that higher ambient temperature was associated with decreases in HRV measures (standard deviation of normal-to-normal intervals, low-frequency power, and high-frequency power) during the warm season but not during the cold season. These warm-season associations were significantly greater when ambient ozone levels were higher (>22.3 ppb) but did not differ according to levels of ambient fine (≤2.5 μm) particulate matter. The authors conclude that temperature and ozone, exposures to both of which are expected to increase with climate change, might act together to worsen cardiovascular health and/or precipitate cardiovascular events via autonomic nervous system dysfunction.
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Affiliation(s)
- Cizao Ren
- Exposure, Epidemiology, and Risk Program, Harvard School of Public Health, Boston, Massachusetts 02215, USA.
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23
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Okamoto-Mizuno K, Tsuzuki K. Effects of season on sleep and skin temperature in the elderly. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2010; 54:401-409. [PMID: 20041336 DOI: 10.1007/s00484-009-0291-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Revised: 11/11/2009] [Accepted: 11/20/2009] [Indexed: 05/28/2023]
Abstract
The effects of season on sleep and skin temperature (Tsk) in 19 healthy, elderly volunteers were investigated. Measurements were obtained in summer, winter, and fall, and activity levels were monitored using a wrist actigraph system for five consecutive days. The temperature and humidity of the bedrooms of the subjects' homes were measured continuously for five days. During actigraphic measurement, Tsk during sleep was measured for two nights. The bedroom temperature and humidity significantly increased in summer compared to winter and fall. In summer, the total sleep time decreased (mean +/- SE min; summer, 350.8 +/- 15.7; winter, 426.5 +/- 14.2; fall, 403.2 +/- 16.4) and wakefulness increased (P < 0.003) compared to those in fall or winter. The sleep efficiency index that was derived from wrist actigraphy was significantly decreased (P < 0.001) in summer (81.4 +/- 2.9%) compared with winter (91.6 +/- 1.3%) or fall (90.2 +/- 1.2%). The forehead Tsk significantly increased, while the chest and thigh Tsks were decreased in summer compared to those in fall or winter. These results suggest that, in the elderly, sleep is disturbed in summer more than in other seasons, and that this disturbance is related to fluctuations in Tsk.
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Affiliation(s)
- Kazue Okamoto-Mizuno
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8566, Japan.
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