1
|
Barrett KT, Roy A, Ebdalla A, Pittman QJ, Wilson RJA, Scantlebury MH. The Impact of Inflammation on Thermal Hyperpnea: Relevance for Heat Stress and Febrile Seizures. Am J Respir Cell Mol Biol 2024; 71:195-206. [PMID: 38597725 PMCID: PMC11299082 DOI: 10.1165/rcmb.2023-0451oc] [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: 12/19/2023] [Accepted: 04/09/2024] [Indexed: 04/11/2024] Open
Abstract
Extreme heat caused by climate change is increasing the transmission of infectious diseases, resulting in a sharp rise in heat-related illness and mortality. Understanding the mechanistic link between heat, inflammation, and disease is thus important for public health. Thermal hyperpnea, and consequent respiratory alkalosis, is crucial in febrile seizures and convulsions induced by heat stress in humans. Here, we address what causes thermal hyperpnea in neonates and how it is affected by inflammation. Transient receptor potential cation channel subfamily V member 1 (TRPV1), a heat-activated channel, is sensitized by inflammation and modulates breathing and thus may play a key role. To investigate whether inflammatory sensitization of TRPV1 modifies neonatal ventilatory responses to heat stress, leading to respiratory alkalosis and an increased susceptibility to hyperthermic seizures, we treated neonatal rats with bacterial LPS, and breathing, arterial pH, in vitro vagus nerve activity, and seizure susceptibility were assessed during heat stress in the presence or absence of a TRPV1 antagonist (AMG-9810) or shRNA-mediated TRPV1 suppression. LPS-induced inflammatory preconditioning lowered the threshold temperature and latency of hyperthermic seizures. This was accompanied by increased tidal volume, minute ventilation, expired CO2, and arterial pH (alkalosis). LPS exposure also elevated vagal spiking and intracellular calcium concentrations in response to hyperthermia. TRPV1 inhibition with AMG-9810 or shRNA reduced the LPS-induced susceptibility to hyperthermic seizures and altered the breathing pattern to fast shallow breaths (tachypnea), making each breath less efficient and restoring arterial pH. These results indicate that inflammation exacerbates thermal hyperpnea-induced respiratory alkalosis associated with increased susceptibility to hyperthermic seizures, primarily mediated by TRPV1 localized to vagus neurons.
Collapse
Affiliation(s)
- Karlene T. Barrett
- Alberta Children’s Hospital Research Institute
- Hotchkiss Brain Institute
- Department of Pediatrics
| | - Arijit Roy
- Hotchkiss Brain Institute
- Department of Physiology and Pharmacology, and
| | - Aya Ebdalla
- Alberta Children’s Hospital Research Institute
| | - Quentin J. Pittman
- Alberta Children’s Hospital Research Institute
- Hotchkiss Brain Institute
- Department of Physiology and Pharmacology, and
| | - Richard J. A. Wilson
- Alberta Children’s Hospital Research Institute
- Hotchkiss Brain Institute
- Department of Physiology and Pharmacology, and
| | - Morris H. Scantlebury
- Alberta Children’s Hospital Research Institute
- Hotchkiss Brain Institute
- Department of Pediatrics
- Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada
| |
Collapse
|
2
|
Bastir M, Sanz-Prieto D, Burgos MA, Pérez-Ramos A, Heuzé Y, Maréchal L, Evteev A, Toro-Ibacache V, Esteban-Ortega F. Beyond skeletal studies: A computational analysis of nasal airway function in climate adaptation. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2024; 184:e24932. [PMID: 38516761 DOI: 10.1002/ajpa.24932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 03/01/2024] [Accepted: 03/12/2024] [Indexed: 03/23/2024]
Abstract
OBJECTIVES Ecogeographic variation in human nasal anatomy has historically been analyzed on skeletal morphology and interpreted in the context of climatic adaptations to respiratory air-conditioning. Only a few studies have analyzed nasal soft tissue morphology, actively involved in air-conditioning physiology. MATERIALS AND METHODS We used in vivo computer tomographic scans of (N = 146) adult individuals from Cambodia, Chile, Russia, and Spain. We conducted (N = 438) airflow simulations during inspiration using computational fluid dynamics to analyze the air-conditioning capacities of the nasal soft tissue in the inflow, functional, and outflow tract, under three different environmental conditions: cold-dry; hot-dry; and hot-humid. We performed statistical comparisons between populations and sexes. RESULTS Subjects from hot-humid regions showed significantly lower air-conditioning capacities than subjects from colder regions in all the three conditions, specifically within the isthmus region in the inflow tract, and the anterior part of the internal functional tract. Posterior to the functional tract, no differences were detected. No differences between sexes were found in any of the tracts and under any of the conditions. DISCUSSION Our statistical analyses support models of climatic adaptations of anterior nasal soft tissue morphology that fit with, and complement, previous research on dry skulls. However, our results challenge a morpho-functional model that attributes air-conditioning capacities exclusively to the functional tract located within the nasal cavity. Instead, our findings support studies that have suggested that both, the external nose and the intra-facial soft tissue airways contribute to efficiently warming and humidifying air during inspiration. This supports functional interpretations in modern midfacial variation and evolution.
Collapse
Affiliation(s)
- Markus Bastir
- Paleoanthropology Group, Department of Paleobiology, National Museum of Natural Sciences-Spanish National Research Council, Madrid, Spain
| | - Daniel Sanz-Prieto
- Paleoanthropology Group, Department of Paleobiology, National Museum of Natural Sciences-Spanish National Research Council, Madrid, Spain
- Fluid Mechanics and Thermal Engineering Group, Department of Thermal and Fluid Engineering, Polytechnic University of Cartagena, Cartagena, Spain
- Department of Biology, Faculty of Sciences, Autonomous University of Madrid, Madrid, Spain
| | - Manuel A Burgos
- Fluid Mechanics and Thermal Engineering Group, Department of Thermal and Fluid Engineering, Polytechnic University of Cartagena, Cartagena, Spain
| | - Alejandro Pérez-Ramos
- Paleobiology, Paleoclimatology, and Paleogeography Group, Department of Ecology and Geology, Faculty of Science, University of Málaga, Malaga, Spain
| | - Yann Heuzé
- CNRS, Ministère de la Culture, PACEA, Université de Bordeaux, Pessac, France
| | - Laura Maréchal
- CNRS, Ministère de la Culture, PACEA, Université de Bordeaux, Pessac, France
| | - Andrej Evteev
- Anuchin Research Institute and Museum of Anthropology, Lomonosov Moscow State University, Moscow, Russia
| | - Viviana Toro-Ibacache
- Center for Quantitative Analysis in Dental Anthropology, Faculty of Dentistry, University of Chile, Santiago, Chile
| | | |
Collapse
|
3
|
Dervišević E. Hyperthermia: Is it always an accidental death? Leg Med (Tokyo) 2024; 68:102418. [PMID: 38335833 DOI: 10.1016/j.legalmed.2024.102418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Accepted: 02/01/2024] [Indexed: 02/12/2024]
Abstract
INTRODUCTION The research aimed to determine individual variations in different core temperature measurements before the experiment, after submersion, after 20 min of exposure for heat stroke. METHODS Rats were divided into three groups depending on the temperature and length of exposure to water: CG, G41-20 and G41-UD. The protocol was made according to the earlier described methodology of heat shock induction. RESULTS A significant difference was observed in the G41-UD group; p < 0.0005. The lowest body temperature of the rats was observed, from normothermia, and the highest temperature after death, 37.87 ± 0.62 °C vs 41.20 ± 0.76 °C, the difference between all three groups is p < 0.0005. CONCLUSION Exposure of Wistar rats to water temperatures in the CG and G41 groups led to a significant change in core temperature. In the control group, the thermoregulatory mechanism firmly established normothermia, while hyperthermia was revealed in the G41 group during the 20-minute exposure.
Collapse
Affiliation(s)
- Emina Dervišević
- Department of Forensic Medicine, Faculty of Medicine, University of Sarajevo, Sarajevo, Bosnia and Herzegovina
| |
Collapse
|
4
|
Watanabe K, Koch Esteves N, Gibson OR, Akiyama K, Watanabe S, González-Alonso J. Heat-related changes in the velocity and kinetic energy of flowing blood influence the human heart's output during hyperthermia. J Physiol 2024; 602:2227-2251. [PMID: 38690610 DOI: 10.1113/jp285760] [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: 10/03/2023] [Accepted: 04/03/2024] [Indexed: 05/02/2024] Open
Abstract
Passive whole-body hyperthermia increases limb blood flow and cardiac output (Q ̇ $\dot Q$ ), but the interplay between peripheral and central thermo-haemodynamic mechanisms remains unclear. Here we tested the hypothesis that local hyperthermia-induced alterations in peripheral blood flow and blood kinetic energy modulate flow to the heart andQ ̇ $\dot Q$ . Body temperatures, regional (leg, arm, head) and systemic haemodynamics, and left ventricular (LV) volumes and functions were assessed in eight healthy males during: (1) 3 h control (normothermic condition); (2) 3 h of single-leg heating; (3) 3 h of two-leg heating; and (4) 2.5 h of whole-body heating. Leg, forearm, and extracranial blood flow increased in close association with local rises in temperature while brain perfusion remained unchanged. Increases in blood velocity with small to no changes in the conduit artery diameter underpinned the augmented limb and extracranial perfusion. In all heating conditions,Q ̇ $\dot Q$ increased in association with proportional elevations in systemic vascular conductance, related to enhanced blood flow, blood velocity, vascular conductance and kinetic energy in the limbs and head (all R2 ≥ 0.803; P < 0.001), but not in the brain. LV systolic (end-systolic elastance and twist) and diastolic functional profiles (untwisting rate), pulmonary ventilation and systemic aerobic metabolism were only altered in whole-body heating. These findings substantiate the idea that local hyperthermia-induced selective alterations in peripheral blood flow modulate the magnitude of flow to the heart andQ ̇ $\dot Q$ through changes in blood velocity and kinetic energy. Localised heat-activated events in the peripheral circulation therefore affect the human heart's output. KEY POINTS: Local and whole-body hyperthermia increases limb and systemic perfusion, but the underlying peripheral and central heat-sensitive mechanisms are not fully established. Here we investigated the regional (leg, arm and head) and systemic haemodynamics (cardiac output:Q ̇ $\dot Q$ ) during passive single-leg, two-leg and whole-body hyperthermia to determine the contribution of peripheral and central thermosensitive factors in the control of human circulation. Single-leg, two-leg, and whole-body hyperthermia induced graded increases in leg blood flow andQ ̇ $\dot Q$ . Brain blood flow, however, remained unchanged in all conditions. Ventilation, extracranial blood flow and cardiac systolic and diastolic functions only increased during whole-body hyperthermia. The augmentedQ ̇ $\dot Q$ with hyperthermia was tightly related to increased limb and head blood velocity, flow and kinetic energy. The findings indicate that local thermosensitive mechanisms modulate regional blood velocity, flow and kinetic energy, thereby controlling the magnitude of flow to the heart and thus the coupling of peripheral and central circulation during hyperthermia.
Collapse
Affiliation(s)
- Kazuhito Watanabe
- Division of Sport, Health and Exercise Sciences, Department of Life Sciences, Brunel University London, Uxbridge, UK
- Faculty of Education and Human Studies, Akita University, Akita, Japan
| | - Nuno Koch Esteves
- Division of Sport, Health and Exercise Sciences, Department of Life Sciences, Brunel University London, Uxbridge, UK
- Research Centre, University College of Osteopathy, London, UK
| | - Oliver R Gibson
- Division of Sport, Health and Exercise Sciences, Department of Life Sciences, Brunel University London, Uxbridge, UK
- Centre for Physical Activity in Health and Disease, Brunel University London, Uxbridge, UK
| | - Koichi Akiyama
- Department of Anesthesiology, Kindai University Hospital, Osaka, Japan
| | - Sumie Watanabe
- Division of Sport, Health and Exercise Sciences, Department of Life Sciences, Brunel University London, Uxbridge, UK
- Faculty of Education and Human Studies, Akita University, Akita, Japan
| | - José González-Alonso
- Division of Sport, Health and Exercise Sciences, Department of Life Sciences, Brunel University London, Uxbridge, UK
| |
Collapse
|
5
|
Skinner BD, Lucas RAI, Lucas SJE. Exposure to passive heat and cold stress differentially modulates cerebrovascular-CO 2 responsiveness. J Appl Physiol (1985) 2024; 136:23-32. [PMID: 37969086 DOI: 10.1152/japplphysiol.00494.2023] [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: 07/20/2023] [Revised: 10/30/2023] [Accepted: 11/13/2023] [Indexed: 11/17/2023] Open
Abstract
Heat and cold stress influence cerebral blood flow (CBF) regulatory factors (e.g., arterial CO2 partial pressure). However, it is unclear whether the CBF response to a CO2 stimulus (i.e., cerebrovascular-CO2 responsiveness) is maintained under different thermal conditions. This study aimed to compare cerebrovascular-CO2 responsiveness between normothermia, passive heat, and cold stress conditions. Sixteen participants (8 females; 25 ± 7 yr) completed two experimental sessions (randomized) comprising normothermic and either passive heat or cold stress conditions. Middle and posterior cerebral artery velocity (MCAv, PCAv) were measured during rest, hypercapnia (5% CO2 inhalation), and hypocapnia (voluntary hyperventilation to an end-tidal CO2 of 30 mmHg). The linear slope of the cerebral blood velocity (CBv) response to changing end-tidal CO2 was calculated to measure cerebrovascular-CO2 responsiveness, and cerebrovascular conductance (CVC) was used to examine responsiveness independent of blood pressure. CBv-CVC-CO2 responsiveness to hypocapnia was greater during heat stress compared with cold stress (MCA: +0.05 ± 0.08 cm/s/mmHg/mmHg, P = 0.04; PCA: +0.02 ± 0.02 cm/s/mmHg/mmHg, P = 0.002). CBv-CO2 responsiveness to hypercapnia decreased during heat stress (MCA: -0.67 ± 0.89 cm/s/mmHg, P = 0.02; PCA: -0.64 ± 0.62 cm/s/mmHg; P = 0.01) and increased during cold stress (MCA: +0.98 ± 1.33 cm/s/mmHg, P = 0.03; PCA: +1.00 ± 0.82 cm/s/mmHg; P = 0.01) compared with normothermia. However, CBv-CVC-CO2 responsiveness to hypercapnia was not different between thermal conditions (P > 0.08). Overall, passive heat, but not cold, stress challenges the maintenance of cerebral perfusion. A greater cerebrovascular responsiveness to hypocapnia during heat stress likely reduces an already impaired cerebrovascular reserve capacity and may contribute to adverse events (e.g., syncope).NEW & NOTEWORTHY This study demonstrates that thermoregulatory-driven perfusion pressure changes, from either cold or heat stress, impact cerebrovascular responsiveness to hypercapnia. Compared with cold stress, heat stress poses a greater challenge to the maintenance of cerebral perfusion during hypocapnia, challenging cerebrovascular reserve capacity while increasing cerebrovascular-CO2 responsiveness. This likely exacerbates cerebral hypoperfusion during heat stress since hyperthermia-induced hyperventilation results in hypocapnia. No regional differences in middle and posterior cerebral artery responsiveness were found with thermal stress.
Collapse
Affiliation(s)
- Bethany D Skinner
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Rebekah A I Lucas
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Samuel J E Lucas
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
- Centre for Human Brain Health, University of Birmingham, Birmingham, United Kingdom
| |
Collapse
|
6
|
Ashe N, Wozniak S, Conner M, Ahmed R, Demetres MR, Makarem N, Tehranifar P, Nandakumar R, Ghosh A. Association of extreme heat events with sleep and cardiovascular health: A scoping review. RESEARCH SQUARE 2023:rs.3.rs-3678410. [PMID: 38196642 PMCID: PMC10775383 DOI: 10.21203/rs.3.rs-3678410/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
BACKGROUND Extreme heat events (EHEs), driven by anthropogenic climate change, exacerbate the risk of cardiovascular disease (CVD), although the underlying mechanisms are unclear. Disturbances in sleep health, caused by excessive heat, may be one way EHEs increase the risk of incident or recurrent CVD. Our objective was to systematically review the empirical peer-reviewed literature on the relationship between EHEs, sleep health, and cardiovascular measures and outcomes, and narratively describe methodologies, evidence, and gaps in this area. METHODS A comprehensive literature search was performed in the following databases from inception - June 2023: Ovid MEDLINE, Ovid EMBASE, CINAHL, Web of Science and The Cochrane Library. Studies retrieved were then screened for eligibility against predefined inclusion/exclusion criteria. RESULTS Of the 2035 records screened, three studies met the inclusion criteria. Cardiovascular (CV) measures described included blood pressure (BP), heart rate (HR), and HR variability (no CVD outcomes were described) and objective and subjective measurements of sleep health outcomes included sleep duration, calmness, ease of falling asleep, ease of awakening, freshness after awakening, and sleep satisfaction. Two studies were controlled trials, and one was a cohort study. During EHEs, individuals slept for shorter periods of time and less efficiently, with greater degrees of HR variability in two of the three studies lasting at most 1-2 days; BP (both systolic and diastolic) significantly decreased during EHEs in two of the studies. No formal assessment of a mediating relationship between EHE exposure, sleep outcomes, and the CV measures was undertaken. CONCLUSIONS There is a paucity of data that examines the link between CVD, sleep, and extreme heat as a possible mechanism of elevated CVD risk during EHEs, despite a strong physiological rationale. Further research is needed to empirically test this relationship rigorously as EHEs become more frequent and their deleterious impacts of health increase.
Collapse
Affiliation(s)
- Nathan Ashe
- Weill Cornell Medical College: Weill Cornell Medicine
| | - Sarah Wozniak
- Weill Cornell Medical College: Weill Cornell Medicine
| | - Malcom Conner
- Weill Cornell Medical College: Weill Cornell Medicine
| | | | | | | | | | | | | |
Collapse
|
7
|
Wait SO, Charkoudian N, Skinner JW, Smith CJ. Combining hypoxia with thermal stimuli in humans: physiological responses and potential sex differences. Am J Physiol Regul Integr Comp Physiol 2023; 324:R677-R690. [PMID: 36971421 PMCID: PMC10202487 DOI: 10.1152/ajpregu.00244.2021] [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: 09/27/2021] [Revised: 03/08/2023] [Accepted: 03/20/2023] [Indexed: 03/29/2023]
Abstract
Increasing prevalence of native lowlanders sojourning to high altitudes (>2,500 m) for recreational, occupational, military, and competitive reasons has generated increased interest in physiological responses to multistressor environments. Exposure to hypoxia poses recognized physiological challenges that are amplified during exercise and further complicated by environments that might include combinations of heat, cold, and high altitude. There is a sparsity of data examining integrated responses in varied combinations of environmental conditions, with even less known about potential sex differences. How this translates into performance, occupational, and health outcomes requires further investigation. Acute hypoxic exposure decreases arterial oxygen saturation, resulting in a reflex hypoxic ventilatory response and sympathoexcitation causing an increase in heart rate, myocardial contractility, and arterial blood pressure, to compensate for the decreased arterial oxygen saturation. Acute altitude exposure impairs exercise performance, for example, reduced time to exhaustion and slower time trials, largely owing to impairments in pulmonary gas exchange and peripheral delivery resulting in reduced V̇o2max. This exacerbates with increasing altitude, as does the risk of developing acute mountain sickness and more serious altitude-related illnesses, but modulation of those risks with additional stressors is unclear. This review aims to summarize and evaluate current literature regarding cardiovascular, autonomic, and thermoregulatory responses to acute hypoxia, and how these may be affected by simultaneous thermal environmental challenges. There is minimal available information regarding sex as a biological variable in integrative responses to hypoxia or multistressor environments; we highlight these areas as current knowledge gaps and the need for future research.
Collapse
Affiliation(s)
- Seaver O Wait
- Department of Public Health and Exercise Science, Appalachian State University, Boone, North Carolina, United States
| | - Nisha Charkoudian
- United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States
| | - Jared W Skinner
- Department of Public Health and Exercise Science, Appalachian State University, Boone, North Carolina, United States
| | - Caroline J Smith
- Department of Public Health and Exercise Science, Appalachian State University, Boone, North Carolina, United States
| |
Collapse
|
8
|
Chu B, Chen R, Liu Q, Wang H. Effects of High Temperature on COVID-19 Deaths in U.S. Counties. GEOHEALTH 2023; 7:e2022GH000705. [PMID: 36852181 PMCID: PMC9958002 DOI: 10.1029/2022gh000705] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 01/18/2023] [Accepted: 02/03/2023] [Indexed: 06/18/2023]
Abstract
The United States of America (USA) was afflicted by extreme heat in the summer of 2021 and some states experienced a record-hot or top-10 hottest summer. Meanwhile, the United States was also one of the countries impacted most by the coronavirus disease 2019 (COVID-19) pandemic. Growing numbers of studies have revealed that meteorological factors such as temperature may influence the number of confirmed COVID-19 cases and deaths. However, the associations between temperature and COVID-19 severity differ in various study areas and periods, especially in periods of high temperatures. Here we choose 119 US counties with large counts of COVID-19 deaths during the summer of 2021 to examine the relationship between COVID-19 deaths and temperature by applying a two-stage epidemiological analytical approach. We also calculate the years of life lost (YLL) owing to COVID-19 and the corresponding values attributable to high temperature exposure. The daily mean temperature is approximately positively correlated with COVID-19 deaths nationwide, with a relative risk of 1.108 (95% confidence interval: 1.046, 1.173) in the 90th percentile of the mean temperature distribution compared with the median temperature. In addition, 0.02 YLL per COVID-19 death attributable to high temperature are estimated at the national level, and distinct spatial variability from -0.10 to 0.08 years is observed in different states. Our results provide new evidence on the relationship between high temperature and COVID-19 deaths, which might help us to understand the underlying modulation of the COVID-19 pandemic by meteorological variables and to develop epidemic policy response strategies.
Collapse
Affiliation(s)
- Bowen Chu
- Joint International Research Laboratory of Atmospheric and Earth System SciencesSchool of Atmospheric SciencesNanjing UniversityNanjingChina
| | - Renjie Chen
- School of Public HealthKey Lab of Public Health Safety of the Ministry of Education and National Health Commission Key Lab of Health Technology AssessmentFudan UniversityShanghaiChina
| | - Qi Liu
- Joint International Research Laboratory of Atmospheric and Earth System SciencesSchool of Atmospheric SciencesNanjing UniversityNanjingChina
- Collaborative Innovation Center of Climate ChangeNanjingChina
| | - Haikun Wang
- Joint International Research Laboratory of Atmospheric and Earth System SciencesSchool of Atmospheric SciencesNanjing UniversityNanjingChina
- Collaborative Innovation Center of Climate ChangeNanjingChina
- Frontiers Science Center for Critical Earth Material CyclingNanjing UniversityNanjingChina
| |
Collapse
|
9
|
Han A, Deng S, Yu J, Zhang Y, Jalaludin B, Huang C. Asthma triggered by extreme temperatures: From epidemiological evidence to biological plausibility. ENVIRONMENTAL RESEARCH 2023; 216:114489. [PMID: 36208788 DOI: 10.1016/j.envres.2022.114489] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 09/25/2022] [Accepted: 10/01/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND There is rapidly growing evidence indicating that extreme temperature is a crucial trigger and potential activator of asthma; however, the effects of extreme temperature on asthma are inconsistently reported and the its potential mechanisms remain undefined. OBJECTIVES This review aims to estimate the impacts of extreme heat, extreme cold, and temperature variations on asthma by systematically summarizing the existing studies from epidemiological evidence to biological plausibility. METHODS We conducted a systematic search in PubMed, Embase, and Web of Science from inception to June 30, 2022, and we retrieved articles of epidemiology and biological studies which assessed associations between extreme temperatures and asthma. This protocol was registered with PROSPERO (CRD42021273613). RESULTS From 12,435 identified records, 111 eligible studies were included in the qualitative synthesis, and 37 articles were included in the meta-analysis (20 for extreme heat, 16 for extreme cold, and 15 for temperature variations). For epidemiological evidence, we found that the synergistic effects of extreme temperatures, indoor/outdoor environments, and individual vulnerabilities are important triggers for asthma attacks, especially when there is extreme heat or cold. Meta-analysis further confirmed the associations, and the pooled relative risks for asthma attacks in extreme heat and extreme cold were 1.07 (95%CI: 1.03-1.12) and 1.20 (95%CI: 1.12-1.29), respectively. Additionally, this review discussed the potential inflammatory mechanisms behind the associations between extreme temperatures and asthma exacerbation, and highlighted the regulatory role of immunological pathways and transient receptor potential ion channels in asthma triggered by extreme temperatures. CONCLUSIONS We concluded that both extreme heat and cold could significantly increase the risk of asthma. Additionally, we proposed a potential mechanistic framework, which is important for understanding the disease pathogenesis that uncovers the complex mechanisms of asthma triggered by extreme temperatures and protects the sensitive individuals from impacts of extreme weather events and climate change.
Collapse
Affiliation(s)
- Azhu Han
- School of Public Health, Sun Yat-sen University, Guangzhou, 510080, China
| | - Shizhou Deng
- School of Public Health, Sun Yat-sen University, Guangzhou, 510080, China
| | - Jiarui Yu
- Shenzhen Health Development Research and Data Management Center, Shenzhen 518028, China, School of Arts and Sciences, Columbia University, New York City, NY, USA
| | - Yali Zhang
- School of Public Health, Sun Yat-sen University, Guangzhou, 510080, China
| | - Bin Jalaludin
- School of Population Health, University of New South Wales, Sydney, Australia
| | - Cunrui Huang
- Vanke School of Public Health, Tsinghua University, Beijing, 100084, China.
| |
Collapse
|
10
|
Arsad FS, Hod R, Ahmad N, Ismail R, Mohamed N, Baharom M, Osman Y, Radi MFM, Tangang F. The Impact of Heatwaves on Mortality and Morbidity and the Associated Vulnerability Factors: A Systematic Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:16356. [PMID: 36498428 PMCID: PMC9738283 DOI: 10.3390/ijerph192316356] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/15/2022] [Accepted: 11/30/2022] [Indexed: 06/17/2023]
Abstract
BACKGROUND This study aims to investigate the current impacts of extreme temperature and heatwaves on human health in terms of both mortality and morbidity. This systematic review analyzed the impact of heatwaves on mortality, morbidity, and the associated vulnerability factors, focusing on the sensitivity component. METHODS This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 flow checklist. Four databases (Scopus, Web of Science, EBSCOhost, PubMed) were searched for articles published from 2012 to 2022. Those eligible were evaluated using the Navigation Guide Systematic Review framework. RESULTS A total of 32 articles were included in the systematic review. Heatwave events increased mortality and morbidity incidence. Sociodemographic (elderly, children, male, female, low socioeconomic, low education), medical conditions (cardiopulmonary diseases, renal disease, diabetes, mental disease), and rural areas were crucial vulnerability factors. CONCLUSIONS While mortality and morbidity are critical aspects for measuring the impact of heatwaves on human health, the sensitivity in the context of sociodemographic, medical conditions, and locality posed a higher vulnerability to certain groups. Therefore, further research on climate change and health impacts on vulnerability may help stakeholders strategize effective plans to reduce the effect of heatwaves.
Collapse
Affiliation(s)
- Fadly Syah Arsad
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Bandar Tun Razak, Kuala Lumpur 56000, Malaysia
| | - Rozita Hod
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Bandar Tun Razak, Kuala Lumpur 56000, Malaysia
| | - Norfazilah Ahmad
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Bandar Tun Razak, Kuala Lumpur 56000, Malaysia
| | - Rohaida Ismail
- Environmental Health Research Centre, Institute for Medical Research, Ministry of Health Malaysia, Shah Alam 40170, Malaysia
| | - Norlen Mohamed
- Environmental Health Unit, Disease Control Division, Ministry of Health Malaysia, Putrajaya 62590, Malaysia
| | - Mazni Baharom
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Bandar Tun Razak, Kuala Lumpur 56000, Malaysia
| | - Yelmizaitun Osman
- Occupational and Environmental Health Unit, Kelantan State Health Department, Ministry of Health Malaysia, Kota Bharu 15590, Malaysia
| | - Mohd Firdaus Mohd Radi
- Surveillance Unit, Kedah State Health Department, Ministry of Health Malaysia, Alor Setar 05400, Malaysia
| | - Fredolin Tangang
- Department of Earth Sciences and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Malaysia
| |
Collapse
|
11
|
Henderson M, Halsey L. The metabolic upper critical temperature of the human thermoneutral zone. J Therm Biol 2022; 110:103380. [DOI: 10.1016/j.jtherbio.2022.103380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 05/11/2022] [Accepted: 10/21/2022] [Indexed: 11/11/2022]
|
12
|
Orysiak J, Młynarczyk M, Piec R, Jakubiak A. Lifestyle and environmental factors may induce airway and systemic inflammation in firefighters. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:73741-73768. [PMID: 36094704 PMCID: PMC9465149 DOI: 10.1007/s11356-022-22479-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Accepted: 08/07/2022] [Indexed: 06/15/2023]
Abstract
Health status depends on multiple genetic and non-genetic factors. Nonheritable factors (such as lifestyle and environmental factors) have stronger impact on immune responses than genetic factors. Firefighters work is associated with exposure to air pollution and heat stress, as well as: extreme physical effort, mental stress, or a changed circadian rhythm, among others. All these factors can contribute to both, short-term and long-term impairment of the physical and mental health of firefighters. Increased levels of some inflammatory markers, such as pro-inflammatory cytokines or C-reactive protein (CRP) have been observed in firefighters, which can lead to local, acute inflammation that promotes a systemic inflammatory response. It is worth emphasizing that inflammation is one of the main hallmarks of cancer and also plays a key role in the development of cardiovascular and respiratory diseases. This article presents possible causes of the development of an inflammatory reaction in firefighters, with particular emphasis on airway inflammation caused by smoke exposure.
Collapse
Affiliation(s)
- Joanna Orysiak
- Central Institute for Labour Protection - National Research Institute, Czerniakowska St. 16, 00-701, Warsaw, Poland.
| | - Magdalena Młynarczyk
- Central Institute for Labour Protection - National Research Institute, Czerniakowska St. 16, 00-701, Warsaw, Poland
| | - Robert Piec
- Institute of Internal Security, The Main School of Fire Service, Słowackiego St. 52/54, 01-629, Warsaw, Poland
| | - Agnieszka Jakubiak
- Department of Heart Failure and Cardiac Rehabilitation, Medical University of Warsaw, Żwirki and Wigury St. 61, 02-091, Warsaw, Poland
| |
Collapse
|
13
|
Tao J, Hossain MZ, Xu Z, Ho HC, Khan MA, Huang C, Zheng H, Ni J, Fan Y, Bogale D, Su H, Cheng J. Protective effect of pneumococcal conjugate vaccination on the short-term association between low temperatures and childhood pneumonia hospitalizations: Interrupted time-series and case-crossover analyses in Matlab, Bangladesh. ENVIRONMENTAL RESEARCH 2022; 212:113156. [PMID: 35331698 DOI: 10.1016/j.envres.2022.113156] [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: 01/27/2022] [Revised: 03/10/2022] [Accepted: 03/18/2022] [Indexed: 06/14/2023]
Abstract
Studies have shown that ambient extreme temperatures (heat and cold) were associated with an increased risk of childhood pneumonia, but the evidence is very limited in low-middle-income countries. It also remains unknown whether pneumococcal conjugate vaccine (PCV) could prevent temperature-related childhood pneumonia. This study collected data on ambient temperature and hospitalizations for childhood pneumonia in Matlab, Bangladesh from 2012 to 2016. Interrupted time series (ITS) analysis was employed to assess the impact of PCV (10-valent) intervention on childhood pneumonia hospitalizations. A time-stratified case-crossover analysis with a conditional logistic regression was performed to examine the association of childhood pneumonia hospitalizations with extreme temperatures and heatwaves before and after PCV10 intervention. Subgroup analyses were conducted to explore the modification effects of seasons, age, gender, and socioeconomic levels on temperature-related childhood pneumonia hospitalizations. We found that after PCV10 intervention, there was a sharp decrease in hospitalizations for childhood pneumonia (relative risk (RR): 0.59, 95% confidence interval (CI): 0.43-0.83). During the study period, heat effects on childhood pneumonia appeared immediately on the current day (odds ratio (OR): 1.28; 95% CI: 1.02-1.60, lag 0), while cold effects appeared 4 weeks later (OR: 1.53, 95% CI: 1.06-2.22, lag 28). Importantly, cold effects decreased significantly after PCV10 (p-value<0.05), but heat and heatwave effects increased after PCV10 (p-value<0.05). Particularly, children from families with a middle or low socioeconomic level, boys, and infants were more susceptible to heat-related pneumonia. This study suggests that PCV10 intervention in Bangladesh may help decrease cold-related not heat-related childhood pneumonia.
Collapse
Affiliation(s)
- Junwen Tao
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China; Anhui Province Key Laboratory of Major Autoimmune Disease, Hefei, China
| | - Mohammad Zahid Hossain
- International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Zhiwei Xu
- School of Public Health, Faculty of Medicine, University of Queensland, 288 Herston Road, Herston, QLD, 4006, Australia
| | - Hung Chak Ho
- Department of Urban Planning and Design, The University of Hong Kong, Hong Kong, China
| | - Md Alfazal Khan
- Matlab Health Research Centre, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Cunrui Huang
- Vanke School of Public Health, Tsinghua University, Beijing, China
| | - Hao Zheng
- Department of Environmental Health, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, China
| | - Jing Ni
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China; Anhui Province Key Laboratory of Major Autoimmune Disease, Hefei, China
| | - Yinguan Fan
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China; Anhui Province Key Laboratory of Major Autoimmune Disease, Hefei, China
| | - Daniel Bogale
- College of Health Sciences, Arsi University, Asela, Ethiopia
| | - Hong Su
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China; Anhui Province Key Laboratory of Major Autoimmune Disease, Hefei, China
| | - Jian Cheng
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China; Anhui Province Key Laboratory of Major Autoimmune Disease, Hefei, China.
| |
Collapse
|
14
|
Jareonsettasin P, Zeicu C, Diehl B, Harper RM, Astin R. Inappropriate Ventilatory Homeostatic Responses in Hospitalized COVID-19 Patients. Front Neurol 2022; 13:909915. [PMID: 35785338 PMCID: PMC9240262 DOI: 10.3389/fneur.2022.909915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 05/19/2022] [Indexed: 11/15/2022] Open
Abstract
Background The clinical presentation of COVID-19 suggests altered breathing control - tachypnoea, relative lack of dyspnoea, and often a discrepancy between severity of clinical and radiological findings. Few studies characterize and analyse the contribution of breathing drivers and their ventilatory and perceptual responses. Aim To establish the prevalence of inappropriate ventilatory and perceptual response in COVID-19, by characterizing the relationships between respiratory rate (RR), dyspnoea and arterial blood gas (ABG) in a cohort of COVID-19 patients at presentation to hospital, and their post-Covid respiratory sequelae at follow-up. Methods We conducted a retrospective cohort study including consecutive adult patients admitted to hospital with confirmed COVID-19 between 1st March 2020 and 30th April 2020. In those with concurrent ABG, RR and documented dyspnoea status on presentation, we documented patient characteristics, disease severity, and outcomes at hospital and 6-week post-discharge. Results Of 492 admissions, 194 patients met the inclusion criteria. Tachypnoea was present in 75% pronounced (RR>30) in 36%, and persisted during sleep. RR correlated with heart rate (HR) (r = 0.2674), temperature (r = 0.2824), CRP (r = 0.2561), Alveolar-arterial (A-a) gradient (r = 0.4189), and lower PaO2/FiO2 (PF) ratio (r = −0.3636). RR was not correlated with any neurological symptoms. Dyspnoea was correlated with RR (r = 0.2932), A-a gradient (r = 0.1723), and lower PF ratio (r = −0.1914), but not correlated with PaO2 (r = −0.1095), PaCO2 (r = −0.0598) or any recorded neurological symptom except for altered consciousness. Impaired ventilatory homeostatic control of pH/PaCO2 [tachypnoea (RR>20), hypocapnia (PaCO2 <4.6 kPa), and alkalosis (pH>7.45)] was observed in 29%. This group, of which 37% reported no dyspnoea, had more severe respiratory disease (A-a gradient 38.9 vs. 12.4 mmHg; PF ratio 120 vs. 238), and higher prevalence of anosmia (21 vs. 15%), dysgeusia (25 vs. 12%), headache (33 vs. 23%) and nausea (33 vs. 14%) with similar rates of new anxiety/depression (26 vs. 23%), but lower incidence of past neurological or psychiatric diagnoses (5 vs. 21%) compared to appropriate responders. Only 5% had hypoxia sufficiently severe to drive breathing (i.e. PaO2 <6.6 kPa). At 6 weeks post-discharge, 24% (8/34) showed a new breathing pattern disorder with no other neurological findings, nor previous respiratory, neurological, or psychiatric disorder diagnoses. Conclusions Impaired homeostatic control of ventilation i.e., tachypnoea, despite hypocapnia to the point of alkalosis appears prevalent in patients admitted to hospital with COVID-19, a finding typically accompanying more severe disease. Tachypnoea prevalence was between 12 and 29%. Data suggest that excessive tachypnoea is driven by both peripheral and central mechanisms, but not hypoxia. Over a third of patients with impaired homeostatic ventilatory control did not experience dyspnoea despite tachypnoea. A subset of followed-up patients developed post-covid breathing pattern disorder.
Collapse
Affiliation(s)
- Prem Jareonsettasin
- Department of Clinical and Experimental Epilepsy, Queen Square Institute of Neurology, University College London, London, United Kingdom
- Division of Medical Specialties, University College London Hospitals NHS Foundation Trust, London, United Kingdom
- *Correspondence: Prem Jareonsettasin
| | - Claudia Zeicu
- Department of Clinical and Experimental Epilepsy, Queen Square Institute of Neurology, University College London, London, United Kingdom
- Division of Medical Specialties, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - Beate Diehl
- Department of Clinical and Experimental Epilepsy, Queen Square Institute of Neurology, University College London, London, United Kingdom
- Department of Clinical Neurophysiology, University College London Hospitals NHS Foundation Trust National Hospital for Neurology and Neurosurgery, London, United Kingdom
| | - Ronald M. Harper
- Department of Neurobiology and the Brain Research Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Rónan Astin
- Division of Medical Specialties, University College London Hospitals NHS Foundation Trust, London, United Kingdom
- NIHR University College London Hospitals Biomedical Research Centre, London, United Kingdom
| |
Collapse
|
15
|
Burhans W, Rossiter Burhans C, Baumgard L. Invited review: Lethal heat stress: The putative pathophysiology of a deadly disorder in dairy cattle. J Dairy Sci 2022; 105:3716-3735. [DOI: 10.3168/jds.2021-21080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 01/11/2022] [Indexed: 01/13/2023]
|
16
|
Physiological Function during Exercise and Environmental Stress in Humans-An Integrative View of Body Systems and Homeostasis. Cells 2022; 11:cells11030383. [PMID: 35159193 PMCID: PMC8833916 DOI: 10.3390/cells11030383] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 11/26/2022] Open
Abstract
Claude Bernard’s milieu intérieur (internal environment) and the associated concept of homeostasis are fundamental to the understanding of the physiological responses to exercise and environmental stress. Maintenance of cellular homeostasis is thought to happen during exercise through the precise matching of cellular energetic demand and supply, and the production and clearance of metabolic by-products. The mind-boggling number of molecular and cellular pathways and the host of tissues and organ systems involved in the processes sustaining locomotion, however, necessitate an integrative examination of the body’s physiological systems. This integrative approach can be used to identify whether function and cellular homeostasis are maintained or compromised during exercise. In this review, we discuss the responses of the human brain, the lungs, the heart, and the skeletal muscles to the varying physiological demands of exercise and environmental stress. Multiple alterations in physiological function and differential homeostatic adjustments occur when people undertake strenuous exercise with and without thermal stress. These adjustments can include: hyperthermia; hyperventilation; cardiovascular strain with restrictions in brain, muscle, skin and visceral organs blood flow; greater reliance on muscle glycogen and cellular metabolism; alterations in neural activity; and, in some conditions, compromised muscle metabolism and aerobic capacity. Oxygen supply to the human brain is also blunted during intense exercise, but global cerebral metabolism and central neural drive are preserved or enhanced. In contrast to the strain seen during severe exercise and environmental stress, a steady state is maintained when humans exercise at intensities and in environmental conditions that require a small fraction of the functional capacity. The impact of exercise and environmental stress upon whole-body functions and homeostasis therefore depends on the functional needs and differs across organ systems.
Collapse
|
17
|
Infrared sauna as exercise-mimetic? Physiological responses to infrared sauna vs exercise in healthy women: A randomized controlled crossover trial. Complement Ther Med 2021; 64:102798. [PMID: 34954348 DOI: 10.1016/j.ctim.2021.102798] [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: 09/21/2021] [Revised: 11/29/2021] [Accepted: 12/22/2021] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Passive heat therapies have been reported to have similar effects on the cardiovascular system as exercise. Studies supporting these findings in healthy populations have predominantly been done with men using warm water immersions or traditional saunas, rather than newer infrared-based saunas. OBJECTIVE To explore short-term thermal and cardiovascular responses in women using an infrared sauna as compared to moderate-intensity exercise. STUDY DESIGN Randomized controlled crossover trial with balanced allocations. SETTING Brisbane, Australia (August 2019 - March 2020) PARTICIPANTS: Ten healthy women (36 ± 9 years) INTERVENTIONS: 45 min of resting, infrared sauna or indoor bicycling PRIMARY OUTCOME MEASURES: tympanic/skin temperatures; respiratory rate; blood pressure; arterial stiffness; heart rate variability RESULTS: Tympanic temperatures were elevated during infrared sauna as compared to both control (mean diff = +1.05 oC ± SEM 0.12 oC, 95% C.I.: 0.73 - 1.36, p < 0.0005) and exercise (mean diff = +0.79 oC ± SEM 0.12 oC, 95% C.I.: 0.49 - 1.08, p < 0.0005). Respiratory rates were higher during exercise as compared to both control (mean diff = +7.66 ± SEM 1.37, 95% C.I.: 4.09 - 11.23, p < 0.0005) and infrared sauna (mean diff = +6.66 ± SEM 1.33, 95% C.I.: 3.20 - 10.11, p < 0.0005). No significant differences in non-invasive measures of blood pressure, arterial stiffness or heart rate variability were detected between any of the interventions. CONCLUSIONS These findings suggest the physiological effects of infrared sauna bathing are underpinned by thermoregulatory-induced responses, more so than exercise-mimetic cardiorespiratory or cardiovascular activations.
Collapse
|
18
|
Borsi SH, Khodadadi N, Khanjani N, Dastoorpoor M. Physiological equivalent temperature (PET) index and respiratory hospital admissions in Ahvaz, southwest of Iran. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:51888-51896. [PMID: 33993447 DOI: 10.1007/s11356-021-14345-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 05/06/2021] [Indexed: 06/12/2023]
Abstract
Although Ahvaz is considered as one of the warmest cities around the world, few epidemiological studies have been conducted on the adverse effects of temperature on human health using thermal indices in this city. This study investigates the relation between physiologically equivalent temperature (PET) and respiratory hospital admissions in Ahvaz. Distributed lag non-linear models (DLNMs) combined with quasi-Poisson regression models were used to investigate the relation between PET and respiratory disease hospital admissions, adjusted for the effect of time trend, air pollutants (NO2, SO2, and PM10), and weekdays. The analysis was performed by utilizing R software. Low PET values significantly decreased the risk of hospital admissions for total respiratory diseases, respiratory diseases in men and women, chronic obstructive pulmonary diseases (COPD), and bronchiectasis. However, low PET (16.9°C) in all lags except lag 0-30 significantly increased the risk of hospital admissions for asthma. The results indicate that in Ahvaz, which has a warm climate, cold weather decreased overall respiratory hospital admissions, except for asthma.
Collapse
Affiliation(s)
- Seyed Hamid Borsi
- Department of Internal Medicine, Air Pollution and Respiratory Diseases Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Narges Khodadadi
- Department of Biostatistics and Epidemiology, Air Pollution and Respiratory Diseases Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Narges Khanjani
- Neurology Research Center, Kerman University of Medical Sciences, Kerman, Iran
| | - Maryam Dastoorpoor
- Department of Biostatistics and Epidemiology, Air Pollution and Respiratory Diseases Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
| |
Collapse
|
19
|
Ebi KL, Capon A, Berry P, Broderick C, de Dear R, Havenith G, Honda Y, Kovats RS, Ma W, Malik A, Morris NB, Nybo L, Seneviratne SI, Vanos J, Jay O. Hot weather and heat extremes: health risks. Lancet 2021; 398:698-708. [PMID: 34419205 DOI: 10.1016/s0140-6736(21)01208-3] [Citation(s) in RCA: 322] [Impact Index Per Article: 107.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 12/15/2020] [Accepted: 05/20/2021] [Indexed: 01/18/2023]
Abstract
Hot ambient conditions and associated heat stress can increase mortality and morbidity, as well as increase adverse pregnancy outcomes and negatively affect mental health. High heat stress can also reduce physical work capacity and motor-cognitive performances, with consequences for productivity, and increase the risk of occupational health problems. Almost half of the global population and more than 1 billion workers are exposed to high heat episodes and about a third of all exposed workers have negative health effects. However, excess deaths and many heat-related health risks are preventable, with appropriate heat action plans involving behavioural strategies and biophysical solutions. Extreme heat events are becoming permanent features of summer seasons worldwide, causing many excess deaths. Heat-related morbidity and mortality are projected to increase further as climate change progresses, with greater risk associated with higher degrees of global warming. Particularly in tropical regions, increased warming might mean that physiological limits related to heat tolerance (survival) will be reached regularly and more often in coming decades. Climate change is interacting with other trends, such as population growth and ageing, urbanisation, and socioeconomic development, that can either exacerbate or ameliorate heat-related hazards. Urban temperatures are further enhanced by anthropogenic heat from vehicular transport and heat waste from buildings. Although there is some evidence of adaptation to increasing temperatures in high-income countries, projections of a hotter future suggest that without investment in research and risk management actions, heat-related morbidity and mortality are likely to increase.
Collapse
Affiliation(s)
- Kristie L Ebi
- Center for Health and the Global Environment, University of Washington, Seattle, WA, USA.
| | - Anthony Capon
- Monash Sustainable Development Institute, Monash University, Melbourne, VIC, Australia; Sydney School of Public Health, Sydney, NSW, Australia
| | - Peter Berry
- Faculty of Environment, University of Waterloo, Waterloo, ON, Canada
| | - Carolyn Broderick
- School of Medical Sciences, UNSW Sydney, NSW, Australia; The Children's Hospital at Westmead, Sydney, NSW, Australia
| | - Richard de Dear
- Indoor Environmental Quality Laboratory, School of Architecture, Design, and Planning, Sydney, NSW, Australia; The University of Sydney, Sydney, NSW, Australia
| | - George Havenith
- Environmental Ergonomics Research Centre, School of Design and Creative Arts, Loughborough University, Loughborough, UK
| | - Yasushi Honda
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - R Sari Kovats
- NIHR Health Protection Research Unit in Environmental Change and Health, London School of Hygiene & Tropical Medicine, London, UK
| | - Wei Ma
- School of Public Health and Climate Change and Health Center, Shandong University, Jinan, China
| | - Arunima Malik
- Discipline of Accounting, Business School, Sydney, NSW, Australia; School of Physics, Faculty of Science, ISA, Sydney, NSW, Australia
| | - Nathan B Morris
- Thermal Ergonomics Laboratory, Sydney, NSW, Australia; Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Lars Nybo
- Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Sonia I Seneviratne
- Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland
| | - Jennifer Vanos
- School of Sustainability, Arizona State University, Tempe, AZ, USA
| | - Ollie Jay
- Thermal Ergonomics Laboratory, Sydney, NSW, Australia; Sydney School of Health Sciences, Sydney, NSW, Australia; Sydney School of Public Health, Sydney, NSW, Australia; Faculty of Medicine and Health, Charles Perkins Centre, Sydney, NSW, Australia
| |
Collapse
|
20
|
Henderson ME, Brayson D, Halsey LG. The cardio-respiratory effects of passive heating and the human thermoneutral zone. Physiol Rep 2021; 9:e14973. [PMID: 34409765 PMCID: PMC8374383 DOI: 10.14814/phy2.14973] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 06/25/2021] [Accepted: 06/26/2021] [Indexed: 12/31/2022] Open
Abstract
The thermoneutral zone (TNZ) defines the range of ambient temperatures at which resting metabolic rate (MR) is at a minimum. While the TNZ lower limit has been characterized, it is still unclear whether there is an upper limit, that is, beyond which MR during rest increases, and if so, what physiological upregulations explain this. We take the first step to fill this knowledge gap by measuring MR and multiple physiological variables in participants exposed to ambient heat stress while resting. Thirteen participants were exposed for an hour to 28℃-50% relative humidity (RH) air, and both 40 and 50℃ each in 25% RH and humid (50% RH) conditions. Core and skin temperatures, blood pressure, sweat-, heart-, and breathing-rate, minute ventilation, and movement levels were recorded throughout each condition. MR increased 35% (p = .015) during exposure to 40℃-25% RH compared to baseline and a further 13% (p = .000) at in 50℃-50%RH. This was not explained by increased fidgeting (p = .26), suggesting physiological upregulation. However, while greater heat stress invoked increases in heart rate (64%, p = .000), minute ventilation (78%, p = .000), and sweat rate (74%. p = .000) when comparing 50℃-50% RH with baseline, the exact size of their relative energy cost is unclear and, therefore, so is their contribution to this increase in MR. Our study shows clear evidence that resting MR increases in humans at high temperature-there is a metabolic upper critical temperature, at least as low as 40℃. Further studies should pinpoint this value and fully explain this increased MR.
Collapse
Affiliation(s)
- Mary E.T. Henderson
- Centre for Research in Ecology, Evolution and BehaviourLife Sciences DepartmentWhitelands CollegeUniversity of RoehamptonLondonUnited Kingdom
| | - Daniel Brayson
- Dubowitz Neuromuscular CentreUCL, Great Ormond Street Institute of Child HealthHolborn, LondonUnited Kingdom
| | - Lewis G Halsey
- Centre for Research in Ecology, Evolution and BehaviourLife Sciences DepartmentWhitelands CollegeUniversity of RoehamptonLondonUnited Kingdom
| |
Collapse
|
21
|
Adams WM, Butke EE, Lee J, Zaplatosch ME. Cooling Capacity of Transpulmonary Cooling and Cold-Water Immersion After Exercise-Induced Hyperthermia. J Athl Train 2021; 56:383-388. [PMID: 33543267 DOI: 10.4085/1062-6050-0146.20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Cold-water immersion (CWI) may not be feasible in some remote settings, prompting the identification of alternative cooling methods as adjunct treatment modalities for exertional heat stroke (EHS). OBJECTIVE To determine the differences in cooling capacities between CWI and the inspiration of cooled air. DESIGN Randomized controlled clinical trial. SETTING Laboratory. PATIENTS OR OTHER PARTICIPANTS A total of 12 recreationally active participants (7 men, 5 women; age = 26 ± 4 years, height = 170.6 ± 10.1 cm, mass = 76.0 ± 18.0 kg, body fat = 18.5% ± 9.7%, peak oxygen uptake = 42.7 ± 8.9 mL·kg-1·min-1). INTERVENTION(S) After exercise in a hot environment (40°C and 40% relative humidity), participants were randomized to 3 cooling conditions: cooling during passive rest (PASS; control), CWI, and the Polar Breeze thermal rehabilitation machine (PB) with which participants inspired cooled air (22.2°C ± 1.0°C). MAIN OUTCOME MEASURE(S) Rectal temperature (TREC) and heart rate were continuously measured throughout cooling until TREC reached 38.25°C. RESULTS Cooling rates during CWI (0.18°C·min-1 ± 0.06°C·min-1) were greater than those during PASS (mean difference [95% confidence interval] of 0.16°C·min-1 [0.13°C·min-1, 0.19°C·min-1]; P < .001) and PB (0.15°C·min-1 [0.12°C·min-1, 0.16°C·min-1]; P < .001). Elapsed time to reach a TREC of 38.25°C was also faster with CWI (9.71 ± 3.30 minutes) than PASS (-58.1 minutes [-77.1, -39.9 minutes]; P < .001) and PB (-46.8 minutes [-65.5, -28.2 minutes]; P < .001). Differences in cooling rates and time to reach a TREC of 38.25°C between PASS and PB were not different (P > .05). CONCLUSIONS Transpulmonary cooling via cooled-air inhalation did not promote an optimal cooling rate (>0.15°C·min-1) for the successful treatment of EHS. In remote settings where EHS is a risk, access and use of treatment methods via CWI or cold-water dousing are imperative to ensuring survival. TRIAL REGISTRY ClinicalTrials.gov (NCT0419026).
Collapse
Affiliation(s)
- William M Adams
- Hydration, Environment, and Thermal Stress Lab, Department of Kinesiology, University of North Carolina at Greensboro
| | - Erin E Butke
- Hydration, Environment, and Thermal Stress Lab, Department of Kinesiology, University of North Carolina at Greensboro
| | - Junyong Lee
- Hydration, Environment, and Thermal Stress Lab, Department of Kinesiology, University of North Carolina at Greensboro
| | - Mitchell E Zaplatosch
- Hydration, Environment, and Thermal Stress Lab, Department of Kinesiology, University of North Carolina at Greensboro
| |
Collapse
|
22
|
Fonseca-Rodríguez O, Sheridan SC, Lundevaller EH, Schumann B. Effect of extreme hot and cold weather on cause-specific hospitalizations in Sweden: A time series analysis. ENVIRONMENTAL RESEARCH 2021; 193:110535. [PMID: 33271141 DOI: 10.1016/j.envres.2020.110535] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 11/18/2020] [Accepted: 11/23/2020] [Indexed: 06/12/2023]
Abstract
Considering that several meteorological variables can contribute to weather vulnerability, the estimation of their synergetic effects on health is particularly useful. The spatial synoptic classification (SSC) has been used in biometeorological applications to estimate the effect of the entire suite of weather conditions on human morbidity and mortality. In this study, we assessed the relationships between extremely hot and dry (dry tropical plus, DT+) and hot and moist (moist tropical plus, MT+) weather types in summer and extremely cold and dry (dry polar plus, DP+) and cold and moist (moist polar, MP+) weather types in winter and cardiovascular and respiratory hospitalizations by age and sex. Time-series quasi-Poisson regression with distributed lags was used to assess the relationship between oppressive weather types and daily hospitalizations over 14 subsequent days in the extended summer (May to August) and 28 subsequent days during the extended winter (November to March) over 24 years in 4 Swedish locations from 1991 to 2014. In summer, exposure to hot weather types appeared to reduce cardiovascular hospitalizations while increased the risk of hospitalizations for respiratory diseases, mainly related to MT+. In winter, the effect of cold weather on both cause-specific hospitalizations was small; however, MP+ was related to a delayed increase in cardiovascular hospitalizations, whilst MP+ and DP + increased the risk of hospitalizations due to respiratory diseases. This study provides useful information for the staff of hospitals and elderly care centers who can help to implement protective measures for patients and residents. Also, our results could be helpful for vulnerable people who can adopt protective measures to reduce health risks.
Collapse
Affiliation(s)
- Osvaldo Fonseca-Rodríguez
- Department of Epidemiology and Global Health, Umeå University, 901 85, Umeå, Sweden; Centre for Demographic and Ageing Research, Umeå University, 901 87, Umeå, Sweden.
| | - Scott C Sheridan
- Department of Geography, Kent State University, Kent, OH, 44242, USA.
| | | | - Barbara Schumann
- Department of Epidemiology and Global Health, Umeå University, 901 85, Umeå, Sweden; Centre for Demographic and Ageing Research, Umeå University, 901 87, Umeå, Sweden.
| |
Collapse
|
23
|
Wang P, Zhang X, Hashizume M, Goggins WB, Luo C. A systematic review on lagged associations in climate-health studies. Int J Epidemiol 2021; 50:1199-1212. [PMID: 33448301 DOI: 10.1093/ije/dyaa286] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 12/18/2020] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Lagged associations in climate-health studies have already been ubiquitously acknowledged in recent years. Despite extensive time-series models having proposed accounting for lags, few studies have addressed the question of maximum-lag specification, which could induce considerable deviations of effect estimates. METHODS We searched the PubMed and Scopus electronic databases for existing climate-health literature in the English language with a time-series or case-crossover study design published during 2000-2019 to summarize the statistical methodologies and reported lags of associations between climate variables and 14 common causes of morbidity and mortality. We also aggregated the results of the included studies by country and climate zone. RESULTS The associations between infectious-disease outcomes and temperatures were found to be lagged for ∼1-2 weeks for influenza, 3-6 weeks for diarrhoea, 7-12 weeks for malaria and 6-16 weeks for dengue fever. Meanwhile, the associations between both cardiovascular and respiratory diseases and hot temperatures lasted for <5 days, whereas the associations between cardiovascular diseases and cold temperatures were observed to be 10-20 days. In addition, rainfall showed a 4- to 10-week lagged association with infectious diarrheal diseases, whereas the association could be further delayed to 8-12 weeks for vector-borne diseases. CONCLUSION Our findings indicated some general patterns for possible lagged associations between some common health outcomes and climatic exposures, and suggested a necessity for a biologically plausible and reasonable definition of the effect lag in the modelling practices for future environmental epidemiological studies.
Collapse
Affiliation(s)
- Pin Wang
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Xuyi Zhang
- Faculty of Architecture, The University of Hong Kong, Hong Kong, China
| | | | - William B Goggins
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Chao Luo
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| |
Collapse
|
24
|
Rivas E, Allie KN, Salvador PM, Schoech L, Martinez M. Sex difference in cerebral blood flow velocity during exercise hyperthermia. J Therm Biol 2020; 94:102741. [PMID: 33292982 DOI: 10.1016/j.jtherbio.2020.102741] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 09/18/2020] [Accepted: 09/21/2020] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Cerebral blood flow and thermal perception during physical exercise under hyperthermia conditions in females are poorly understood. Because sex differences exist for blood pressure control, resting middle cerebral artery velocity (MCAVmean), and pain, we tested the hypothesis that females would have greater reductions in MCAvmean and increased thermal perceptual strain during exercise hyperthermia compared to males. METHODS Twenty-two healthy active males and females completed 60 min of matched exercise metabolic heat production in a 1) control cool (24.0 ± 0.0 °C; 14.4 ± 3.4% Rh) and 2) hot (42.3 ± 0.3 °C; 28.4 ± 5.2% Rh) conditions in random order, separated by at least 3 days while MCAvmean, thermal comfort, and preference was obtained during the exercise. RESULTS Compared to 36 °C mean body temperature (Mbt), as hyperthermia increased to 39 °C Mbt, females had a greater reduction in absolute (MCAvmean), and relative change (%Δ MCAvmean) and conductance (%Δ MCAvmean conductance) in MCAVmean compared to males (Interaction: Temperature x Sex, P ≤ 0.002). During exercise in cool conditions, absolute and conductance MCAvmean was maintained from rest through exercise; however, females had greater MCAVmean compared to males (Main effect: Sex, P < 0.0008). We also found disparities in females' perceptual thermal comfort and thermal preference. These differences may be associated with a greater reduction in partial pressure of end-tidal CO2, and different cardiovascular and blood pressure control to exercise under hyperthermia. CONCLUSIONS In summary, females exercise cerebral blood flow velocity is reduced to a greater extent (25% vs 15%) and the initial reduction occurs at lower hyperthermia mean body temperatures (~38 °C vs ~39 °C) and are under greater thermal perceptual strain compared to males.
Collapse
Affiliation(s)
- Eric Rivas
- Exercise & Thermal Integrative Physiology Laboratory, Texas Tech University, Lubbock, TX, USA; Department of Kinesiology & Sport Management, Texas Tech University, Lubbock, TX, USA; KBR, Human Physiology, Performance, Protection & Operations Laboratory, NASA Johnson Space Center, Houston, TX, USA.
| | - Kyleigh N Allie
- Exercise & Thermal Integrative Physiology Laboratory, Texas Tech University, Lubbock, TX, USA; Department of Kinesiology & Sport Management, Texas Tech University, Lubbock, TX, USA
| | - Paolo M Salvador
- Exercise & Thermal Integrative Physiology Laboratory, Texas Tech University, Lubbock, TX, USA
| | - Lauren Schoech
- Exercise & Thermal Integrative Physiology Laboratory, Texas Tech University, Lubbock, TX, USA
| | - Mauricio Martinez
- Exercise & Thermal Integrative Physiology Laboratory, Texas Tech University, Lubbock, TX, USA; Department of Kinesiology & Sport Management, Texas Tech University, Lubbock, TX, USA
| |
Collapse
|
25
|
Anenberg SC, Haines S, Wang E, Nassikas N, Kinney PL. Synergistic health effects of air pollution, temperature, and pollen exposure: a systematic review of epidemiological evidence. Environ Health 2020; 19:130. [PMID: 33287833 PMCID: PMC7720572 DOI: 10.1186/s12940-020-00681-z] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 11/30/2020] [Indexed: 05/29/2023]
Abstract
BACKGROUND Exposure to heat, air pollution, and pollen are associated with health outcomes, including cardiovascular and respiratory disease. Studies assessing the health impacts of climate change have considered increased exposure to these risk factors separately, though they may be increasing simultaneously for some populations and may act synergistically on health. Our objective is to systematically review epidemiological evidence for interactive effects of multiple exposures to heat, air pollution, and pollen on human health. METHODS We systematically searched electronic literature databases (last search, April 29, 2019) for studies reporting quantitative measurements of associations between at least two of the exposures and mortality from any cause and cardiovascular and respiratory morbidity and mortality specifically. Following the Navigation Guide systematic review methodology, we evaluated the risk of bias of individual studies and the overall quality and strength of evidence. RESULTS We found 56 studies that met the inclusion criteria. Of these, six measured air pollution, heat, and pollen; 39 measured air pollution and heat; 10 measured air pollution and pollen; and one measured heat and pollen. Nearly all studies were at risk of bias from exposure assessment error. However, consistent exposure-response across studies led us to conclude that there is overall moderate quality and sufficient evidence for synergistic effects of heat and air pollution. We concluded that there is overall low quality and limited evidence for synergistic effects from simultaneous exposure to (1) air pollution, pollen, and heat; and (2) air pollution and pollen. With only one study, we were unable to assess the evidence for synergistic effects of heat and pollen. CONCLUSIONS If synergistic effects between heat and air pollution are confirmed with additional research, the health impacts from climate change-driven increases in air pollution and heat exposure may be larger than previously estimated in studies that consider these risk factors individually.
Collapse
Affiliation(s)
- Susan C. Anenberg
- Milken Institute School of Public Health, George Washington University, 950 New Hampshire Ave NW, Washington, DC 20052 USA
| | - Shannon Haines
- Milken Institute School of Public Health, George Washington University, 950 New Hampshire Ave NW, Washington, DC 20052 USA
- Now at: American Lung Association, Springfield, IL USA
| | - Elizabeth Wang
- Milken Institute School of Public Health, George Washington University, 950 New Hampshire Ave NW, Washington, DC 20052 USA
| | - Nicholas Nassikas
- Department of Pulmonary, Critical Care, and Sleep Medicine, Brown University Alpert Medical School, Providence, RI 02903 USA
| | | |
Collapse
|
26
|
Heat, Heatwaves and Cardiorespiratory Hospital Admissions in Helsinki, Finland. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17217892. [PMID: 33126485 PMCID: PMC7663418 DOI: 10.3390/ijerph17217892] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 10/16/2020] [Accepted: 10/27/2020] [Indexed: 01/03/2023]
Abstract
Background: There is a lack of knowledge concerning the effects of ambient heat exposure on morbidity in Northern Europe. Therefore, this study aimed to evaluate the relationships of daily summertime temperature and heatwaves with cardiorespiratory hospital admissions in the Helsinki metropolitan area, Finland. Methods: Time series models adjusted for potential confounders, such as air pollution, were used to investigate the associations of daily temperature and heatwaves with cause-specific cardiorespiratory hospital admissions during summer months of 2001-2017. Daily number of hospitalizations was obtained from the national hospital discharge register and weather information from the Finnish Meteorological Institute. Results: Increased daily temperature was associated with a decreased risk of total respiratory hospital admissions and asthma. Heatwave days were associated with 20.5% (95% CI: 6.9, 35.9) increased risk of pneumonia admissions and during long or intense heatwaves also with total respiratory admissions in the oldest age group (≥75 years). There were also suggestive positive associations between heatwave days and admissions due to myocardial infarction and cerebrovascular diseases. In contrast, risk of arrhythmia admissions decreased 20.8% (95% CI: 8.0, 31.8) during heatwaves. Conclusions: Heatwaves, rather than single hot days, are a health threat affecting morbidity even in a Northern climate.
Collapse
|
27
|
Fonseca-Rodríguez O, Sheridan SC, Lundevaller EH, Schumann B. Hot and cold weather based on the spatial synoptic classification and cause-specific mortality in Sweden: a time-stratified case-crossover study. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2020; 64:1435-1449. [PMID: 32328787 PMCID: PMC7445203 DOI: 10.1007/s00484-020-01921-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 02/12/2020] [Accepted: 04/13/2020] [Indexed: 06/11/2023]
Abstract
The spatial synoptic classification (SSC) is a holistic categorical assessment of the daily weather conditions at specific locations; it is a useful tool for assessing weather effects on health. In this study, we assessed (a) the effect of hot weather types and the duration of heat events on cardiovascular and respiratory mortality in summer and (b) the effect of cold weather types and the duration of cold events on cardiovascular and respiratory mortality in winter. A time-stratified case-crossover design combined with a distributed lag nonlinear model was carried out to investigate the association of weather types with cause-specific mortality in two southern (Skåne and Stockholm) and two northern (Jämtland and Västerbotten) locations in Sweden. During summer, in the southern locations, the Moist Tropical (MT) and Dry Tropical (DT) weather types increased cardiovascular and respiratory mortality at shorter lags; both hot weather types substantially increased respiratory mortality mainly in Skåne. The impact of heat events on mortality by cardiovascular and respiratory diseases was more important in the southern than in the northern locations at lag 0. The cumulative effect of MT, DT and heat events lagged over 14 days was particularly high for respiratory mortality in all locations except in Jämtland, though these did not show a clear effect on cardiovascular mortality. During winter, the dry polar and moist polar weather types and cold events showed a negligible effect on cardiovascular and respiratory mortality. This study provides valuable information about the relationship between hot oppressive weather types with cause-specific mortality; however, the cold weather types may not capture sufficiently effects on cause-specific mortality in this sub-Arctic region.
Collapse
Affiliation(s)
- Osvaldo Fonseca-Rodríguez
- Department of Epidemiology and Global Health, Umeå University, 901 87, Umeå, Sweden.
- Centre for Demographic and Ageing Research, Umeå University, 901 87, Umeå, Sweden.
| | - Scott C Sheridan
- Department of Geography, Kent State University, Kent, OH, 44242, USA
| | | | - Barbara Schumann
- Department of Epidemiology and Global Health, Umeå University, 901 87, Umeå, Sweden
- Centre for Demographic and Ageing Research, Umeå University, 901 87, Umeå, Sweden
| |
Collapse
|
28
|
Van Cutsem J, Roelands B, De Pauw K, Meeusen R, Marcora S. Combined reply to comments on: Van Cutsem, J., Roelands, B., De Pauw, K., Meeusen, R., & Marcora, S. (2019). Subjective thermal strain impairs endurance performance in a temperate environment. Physiology & Behavior, 202, 36-44. Physiol Behav 2020; 221:112880. [PMID: 32201169 DOI: 10.1016/j.physbeh.2020.112880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 03/16/2020] [Indexed: 11/29/2022]
Affiliation(s)
- Jeroen Van Cutsem
- Human Physiology Research Group, Vrije Universiteit Brussel, Brussel, Belgium; Endurance Research Group, School of Sport and Exercise Sciences, University of Kent, Canterbury, United Kingdom; VIPER Research Unit, Royal Military Academy, Brussels, Belgium
| | - Bart Roelands
- Human Physiology Research Group, Vrije Universiteit Brussel, Brussel, Belgium
| | - Kevin De Pauw
- Human Physiology Research Group, Vrije Universiteit Brussel, Brussel, Belgium
| | - Romain Meeusen
- Human Physiology Research Group, Vrije Universiteit Brussel, Brussel, Belgium
| | - Samuele Marcora
- Endurance Research Group, School of Sport and Exercise Sciences, University of Kent, Canterbury, United Kingdom; Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Bologna, Italy.
| |
Collapse
|
29
|
Zhao Q, Li S, Coelho MDSZS, Saldiva PHN, Xu R, Huxley RR, Abramson MJ, Guo Y. Ambient heat and hospitalisation for COPD in Brazil: a nationwide case-crossover study. Thorax 2019; 74:1031-1036. [DOI: 10.1136/thoraxjnl-2019-213486] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 07/31/2019] [Accepted: 08/20/2019] [Indexed: 11/03/2022]
Abstract
BackgroundHeat exposure has been related to increased morbidity and mortality for several health outcomes. There is little evidence whether this is also true for COPD. This study quantified the relationship between ambient heat and hospitalisation for COPD in the Brazilian population.MethodsData on hospitalisations for COPD and weather conditions were collected from 1642 cities during the 2000–2015 hot seasons. A time-stratified, case-crossover design was used for city-specific analyses, which were then pooled at the regional and national levels using random-effect meta-analyses. Stratified analyses were performed by sex, age group and early/late hot season. Annual change in the association was examined using a random-effect meta-regression model.ResultsThe OR of hospitalisation was 1.05 (95% CI 1.04 to 1.06) for every 5℃ increase in daily mean temperature at the national level, with the effect estimate stronger in the late hot season compared with the early hot season. The effect was similar in women and in men but was greatest for those aged ≥75 years. The association was stronger in the central west and southeast regions and minimal in the northeast. Assuming a causal relationship, 7.2% of admissions were attributable to heat exposure. There was no significant temporal decline in the impact of ambient heat over the 16-year study period.ConclusionIn Brazil, exposure to ambient heat was positively associated with hospitalisation for COPD, particularly during the late hot season. These data add to the growing evidence base implicating global warming as being an important contributor to the future healthcare burden.
Collapse
|
30
|
Marks TN, Maddux SD, Butaric LN, Franciscus RG. Climatic adaptation in human inferior nasal turbinate morphology: Evidence from Arctic and equatorial populations. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2019; 169:498-512. [PMID: 30993687 DOI: 10.1002/ajpa.23840] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 02/26/2019] [Accepted: 04/04/2019] [Indexed: 01/26/2023]
Abstract
OBJECTIVES The nasal turbinates directly influence the overall size, shape, and surface area of the nasal passages, and thus contribute to intranasal heat and moisture exchange. However, unlike the encapsulating walls of the nasal cavity, ecogeographic variation in nasal turbinate morphology among humans has not yet been established. Here we investigate variation in inferior nasal turbinate morphology in two populations from climatically extreme environments. MATERIALS AND METHODS Twenty-three linear measurements of the inferior turbinate, nasal cavity walls, and airway passages were collected from CT scans of indigenous modern human crania from Equatorial Africa (n = 35) and the Arctic Circle (n = 35). MANOVA and ANCOVA were employed to test for predicted regional and sex differences in morphology between the samples. RESULTS Significant morphological differences were identified between the two regional samples, with no evidence of significant sexual dimorphism or region-sex interaction effect. Individuals from the Arctic Circle possessed superoinferiorly and mediolaterally larger inferior turbinates compared to Equatorial Africans. In conjunction with the surrounding nasal cavity walls, these differences in turbinate morphology produced airway dimensions that were both consistent with functional expectations and more regionally distinct than either skeletal component independently. CONCLUSION This study documents the existence of ecogeographic variation in human nasal turbinate morphology reflecting climate-mediated evolutionary demands on intranasal heat and moisture exchange. Humans adapted to cold-dry environments exhibit turbinate morphologies that enhance contact between respired air and nasal mucosa to facilitate respiratory air conditioning. Conversely, humans adapted to hot-humid environments exhibit turbinate morphologies that minimize air-to-mucosa contact, likely to minimize airflow resistance and/or facilitate expiratory heat-shedding.
Collapse
Affiliation(s)
- Tarah N Marks
- Department of Anthropology, University of Iowa, Iowa City, Iowa
| | - Scott D Maddux
- Center for Anatomical Sciences, University of North Texas Health Science Center, Fort Worth, Texas
| | | | | |
Collapse
|
31
|
Massaroni C, Nicolò A, Lo Presti D, Sacchetti M, Silvestri S, Schena E. Contact-Based Methods for Measuring Respiratory Rate. SENSORS (BASEL, SWITZERLAND) 2019; 19:E908. [PMID: 30795595 PMCID: PMC6413190 DOI: 10.3390/s19040908] [Citation(s) in RCA: 125] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 02/15/2019] [Accepted: 02/17/2019] [Indexed: 01/05/2023]
Abstract
There is an ever-growing demand for measuring respiratory variables during a variety of applications, including monitoring in clinical and occupational settings, and during sporting activities and exercise. Special attention is devoted to the monitoring of respiratory rate because it is a vital sign, which responds to a variety of stressors. There are different methods for measuring respiratory rate, which can be classed as contact-based or contactless. The present paper provides an overview of the currently available contact-based methods for measuring respiratory rate. For these methods, the sensing element (or part of the instrument containing it) is attached to the subject's body. Methods based upon the recording of respiratory airflow, sounds, air temperature, air humidity, air components, chest wall movements, and modulation of the cardiac activity are presented. Working principles, metrological characteristics, and applications in the respiratory monitoring field are presented to explore potential development and applicability for each method.
Collapse
Affiliation(s)
- Carlo Massaroni
- Unit of Measurements and Biomedical Instrumentation, Department of Engineering, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo, 21, 00128 Rome, Italy.
| | - Andrea Nicolò
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", 00135 Rome, Italy.
| | - Daniela Lo Presti
- Unit of Measurements and Biomedical Instrumentation, Department of Engineering, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo, 21, 00128 Rome, Italy.
| | - Massimo Sacchetti
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", 00135 Rome, Italy.
| | - Sergio Silvestri
- Unit of Measurements and Biomedical Instrumentation, Department of Engineering, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo, 21, 00128 Rome, Italy.
| | - Emiliano Schena
- Unit of Measurements and Biomedical Instrumentation, Department of Engineering, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo, 21, 00128 Rome, Italy.
| |
Collapse
|
32
|
Cao Y, Ichikawa Y, Sasaki Y, Ogawa T, Hiroyama T, Enomoto Y, Fujii N, Nishiyasu T. Expiratory flow limitation under moderate hypobaric hypoxia does not influence ventilatory responses during incremental running in endurance runners. Physiol Rep 2019; 7:e13996. [PMID: 30714335 PMCID: PMC6360241 DOI: 10.14814/phy2.13996] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Accepted: 01/12/2019] [Indexed: 11/24/2022] Open
Abstract
We tested whether expiratory flow limitation (EFL) occurs in endurance athletes in a moderately hypobaric hypoxic environment equivalent to 2500 m above sea level and, if so, whether EFL inhibits peak ventilation ( V ˙ Epeak ), thereby exacerbating the hypoxia-induced reduction in peak oxygen uptake ( V ˙ O2peak ). Seventeen young male endurance runners performed incremental exhaustive running on separate days under hypobaric hypoxic (560 mmHg) and normobaric normoxic (760 mmHg) conditions. Oxygen uptake ( V ˙ O2 ), minute ventilation ( V ˙ E), arterial O2 saturation (SpO2 ), and operating lung volume were measured throughout the incremental exercise. Among the runners tested, 35% exhibited EFL (EFL group, n = 6) in the hypobaric hypoxic condition, whereas the rest did not (Non-EFL group, n = 11). There were no differences between the EFL and Non-EFL groups for V ˙ Epeak and V ˙ O2peak under either condition. Percent changes in V ˙ Epeak (4 ± 4 vs. 2 ± 4%) and V ˙ O2peak (-18 ± 6 vs. -16 ± 6%) from normobaric normoxia to hypobaric hypoxia also did not differ between the EFL and Non-EFL groups (all P > 0.05). No differences in maximal running velocity, SpO2 , or operating lung volume were detected between the two groups under either condition. These results suggest that under the moderate hypobaric hypoxia (2500 m above sea level) frequently used for high-attitude training, ~35% of endurance athletes may exhibit EFL, but their ventilatory and metabolic responses during maximal exercise are similar to those who do not exhibit EFL.
Collapse
Affiliation(s)
- Yinhang Cao
- Faculty of Health and Sport SciencesUniversity of TsukubaIbarakiJapan
| | - Yuhei Ichikawa
- Faculty of Health and Sport SciencesUniversity of TsukubaIbarakiJapan
| | - Yosuke Sasaki
- Faculty of Health and Sport SciencesUniversity of TsukubaIbarakiJapan
- Faculty of EconomicsNiigata Sangyo UniversityKashiwazakiJapan
| | - Takeshi Ogawa
- Department of Physical EducationOsaka Kyoiku UniversityOsakaJapan
| | - Tsutomu Hiroyama
- Faculty of Health and Sport SciencesUniversity of TsukubaIbarakiJapan
| | - Yasushi Enomoto
- Faculty of Health and Sport SciencesUniversity of TsukubaIbarakiJapan
| | - Naoto Fujii
- Faculty of Health and Sport SciencesUniversity of TsukubaIbarakiJapan
| | - Takeshi Nishiyasu
- Faculty of Health and Sport SciencesUniversity of TsukubaIbarakiJapan
| |
Collapse
|
33
|
Barrett KT, Roy A, Rivard KB, Wilson RJ, Scantlebury MH. Vagal TRPV1 activation exacerbates thermal hyperpnea and increases susceptibility to experimental febrile seizures in immature rats. Neurobiol Dis 2018; 119:172-189. [DOI: 10.1016/j.nbd.2018.08.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 07/20/2018] [Accepted: 08/07/2018] [Indexed: 12/22/2022] Open
|
34
|
Veilleux JC, Zielinski MJ, Moyen NE, Tucker MA, Dougherty EK, Ganio MS. The effect of passive heat stress on distress andself-control in male smokers and non-smokers. The Journal of General Psychology 2018; 145:342-361. [PMID: 30358519 DOI: 10.1080/00221309.2018.1494127] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
In the current study, we tested the effects of core body temperature increases (e.g. heat stress) on affect, self-reported physical discomfort, and subsequent self-control in male smokers and nonsmokers using a novel passive heat stress paradigm, within a distress tolerance framework. Twenty-eight men (14 smokers), completed both heat stress and control sessions in randomized order. Results revealed that increases in core body temperature were associated with increased anxiety, irritability, and body discomfort as well as decreased happiness, with stronger effects for smokers. Smokers and nonsmokers both evidenced less self-control during the heat session and did not differ on this measure, nor on a measure of interoceptive sensitivity. The current study indicates that heat stress is a viable method for studying distress tolerance in men, and suggests the value in examining dynamic changes in self-control as a function of distress. Implications will be discussed for distress tolerance in general and smokers in specific.
Collapse
|
35
|
Sackett JR, Schlader ZJ, O'Leary MC, Chapman CL, Johnson BD. Central chemosensitivity is augmented during 2 h of thermoneutral head-out water immersion in healthy men and women. Exp Physiol 2018. [DOI: 10.1113/ep086870] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- James R. Sackett
- Center for Research and Education in Special Environments; Department of Exercise and Nutrition Sciences; University at Buffalo; Buffalo NY 14214 USA
| | - Zachary J. Schlader
- Center for Research and Education in Special Environments; Department of Exercise and Nutrition Sciences; University at Buffalo; Buffalo NY 14214 USA
| | - Morgan C. O'Leary
- Center for Research and Education in Special Environments; Department of Exercise and Nutrition Sciences; University at Buffalo; Buffalo NY 14214 USA
| | - Christopher L. Chapman
- Center for Research and Education in Special Environments; Department of Exercise and Nutrition Sciences; University at Buffalo; Buffalo NY 14214 USA
| | - Blair D. Johnson
- Center for Research and Education in Special Environments; Department of Exercise and Nutrition Sciences; University at Buffalo; Buffalo NY 14214 USA
| |
Collapse
|
36
|
Abstract
The human autonomic nervous system participates in the control of thermoregulatory responses that are employed to regulate core temperature following deviations of skin temperature and/or core temperature from their respective resting values. This permits a regulation of the core temperature (TC) at 37.0 ± 1°C with superimposed circadian variations in both sexes and menstrual cycle-associated variations in premenopausal women. When rendered hyperthermic, passively by heat exposure while at rest or actively during exercise, humans engage heat loss or thermolytic responses, including eccrine sweating and cutaneous vasodilatation. A third, less studied, human thermolytic response is thermal panting, and this response is the focus of this review. Human thermal panting was first described over a century ago. It has since been shown to be a reproducible response showing some similar patterns of breathing in species that employ panting as their sole thermolytic heat loss response. The contribution of human panting as a thermolytic response, however, remains controversial. This review highlights both past and recent evidence supporting that hyperthermic humans have a panting pattern of breathing that plays an important role in human thermoregulation.
Collapse
Affiliation(s)
- Matthew D White
- Laboratory for Exercise and Environmental Physiology, Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada.
| |
Collapse
|
37
|
Barrett KT, Daubenspeck JA, Wilson RJA. Pituitary adenylate cyclase-activating polypeptide drives cardiorespiratory responses to heat stress in neonatal mice. Am J Physiol Regul Integr Comp Physiol 2017; 313:R385-R394. [DOI: 10.1152/ajpregu.00118.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 06/05/2017] [Accepted: 06/27/2017] [Indexed: 11/22/2022]
Abstract
The neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) has emerged as a principal and rate-limiting regulator of physiological stress responses in adult rodents and has been implicated in sudden infant death syndrome (SIDS). Recent studies show that PACAP plays a role in neonatal cardiorespiratory responses to hypoxia, hypercapnia, and hypothermia, but not hyperthermia, which is often associated with SIDS. Here we tested the hypothesis that, consistent with a role in SIDS, PACAP is involved in regulating the neonatal cardiorespiratory responses to severe heat. To address this, we used head-out plethysmography and surface ECG electrodes to study the cardiorespiratory physiology of conscious neonatal PACAP-null and wild-type mice at ambient temperatures of 32°C (baseline) and 40°C (heat stress). We also assessed body surface temperature as an indicator of cutaneous heat loss. Our results show that wild-type neonatal mice respond to heat stress by increasing ventilation ( P = 0.007) and associated expired CO2 ( P = 0.041), heart rate ( P < 0.001), and cutaneous heat loss ( P < 0.001). In PACAP-null neonates, this heat response is impaired, as indicated by a decrease in ventilation ( P = 0.04) and associated expired CO2 ( P = 0.006) and a blunted increase in heart rate ( P = 0.001) and cutaneous heat loss ( P = 0.0002). In addition, heart rate variability at baseline was lower in PACAP-null neonates than wild-type controls ( P < 0.01). These results suggest that, during heat stress, PACAP is important for neonatal cardiorespiratory responses that help regulate body temperature. Abnormal PACAP regulation could, therefore, contribute to neonatal disorders in which the autonomic response to stress is impaired, such as SIDS.
Collapse
Affiliation(s)
- Karlene T. Barrett
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada; and
| | - John A. Daubenspeck
- Department of Physiology and Neurobiology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire
| | - Richard J. A. Wilson
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada; and
| |
Collapse
|
38
|
Davis JT, Hay MW, Hardin AM, White MD, Lovering AT. Effect of a patent foramen ovale in humans on thermal responses to passive cooling and heating. J Appl Physiol (1985) 2017; 123:1423-1432. [PMID: 28819008 DOI: 10.1152/japplphysiol.01032.2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 08/11/2017] [Accepted: 08/11/2017] [Indexed: 11/22/2022] Open
Abstract
Humans with a patent foramen ovale (PFO) have a higher esophageal temperature (Tesoph) than humans without a PFO (PFO-). Thus the presence of a PFO might also be associated with differences in thermal responsiveness to passive cooling and heating such as shivering and hyperpnea, respectively. The purpose of this study was to determine whether thermal responses to passive cooling and heating are different between PFO- subjects and subjects with a PFO (PFO+). We hypothesized that compared with PFO- subjects PFO+ subjects would cool down more rapidly and heat up slower and that PFO+ subjects who experienced thermal hyperpnea would have a blunted increase in ventilation. Twenty-seven men (13 PFO+) completed two trials separated by >48 h: 1) 60 min of cold water immersion (19.5 ± 0.9°C) and 2) 30 min of hot water immersion (40.5 ± 0.2°C). PFO+ subjects had a higher Tesoph before and during cold water and hot water immersion (P < 0.05). However, the rate of temperature change was similar between groups for each condition. Within a subset of 18 subjects (8 PFO+) who experienced thermal hyperpnea, PFO+ subjects experienced thermal hyperpnea at a higher absolute Tesoph but with a blunted magnitude compared with PFO- subjects. These data suggest that PFO+ subjects have a higher Tesoph at rest and have blunted thermal hyperpnea during passive heating.NEW & NOTEWORTHY Patent foramen ovale (PFO) is found in ~25-40% of the population. The presence of a PFO appears to be associated with a greater core body temperature and blunted ventilatory responses during passive heating. The reason for this blunted ventilatory response to passive heating is unknown but may suggest differences in thermal sensitivity in PFO+ subjects compared with PFO- subjects.
Collapse
Affiliation(s)
- James T Davis
- Department of Kinesiology, Recreation, and Sport, Indiana State University, Terre Haute, Indiana
| | - Madeline W Hay
- Department of Human Physiology, University of Oregon, Eugene, Oregon; and
| | - Alyssa M Hardin
- Department of Human Physiology, University of Oregon, Eugene, Oregon; and
| | - Matthew D White
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Vancouver, British Columbia, Canada
| | - Andrew T Lovering
- Department of Human Physiology, University of Oregon, Eugene, Oregon; and
| |
Collapse
|
39
|
Sarnat HB, Scantlebury MH. Novel Inflammatory Neuropathology in Immature Brain: (1) Fetal Tuberous Sclerosis, (2) Febrile Seizures, (3) α-B-crystallin, and (4) Role of Astrocytes. Semin Pediatr Neurol 2017; 24:152-160. [PMID: 29103422 DOI: 10.1016/j.spen.2017.08.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Though the term "inflammation" is traditionally defined as proliferation or infiltration of lymphatic cells of the lymphatic immune system and macrophages or as immunoreactive proteins including cytokines, interleukins and major histocompatibility complexes, recently recognized reactions to tissue injury also are inflammation, often occurring in the central nervous system in conditions where they previously were not anticipated and where they may play a role in both pathogenesis and repair. We highlight 4 such novel inflammatory conditions revealed by neuropathologic studies: (1) inflammatory markers and cells in the brain of human fetuses with tuberous sclerosis complex and perhaps other disorders of the mechanistic target of rapamycin genetic or metabolic pathway, (2) inflammatory markers in the brain related to febrile seizures of infancy and early childhood, (3) heat-shock protein upregulation in glial cells and neurons at sites of chronic epileptic foci, and (4) the emerging role of astrocytes in the presence of and participation in inflammation. Novel evidence shows that cerebral inflammation plays a role in some genetic diseases as early as midgestation and thus is not always acquired postnatally or in adult life.
Collapse
Affiliation(s)
- Harvey B Sarnat
- Department of Pediatrics, University of Calgary Cumming School of Medicine and Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada; Department of Pathology and Laboratory Medicine (Neuropathology), University of Calgary Cumming School of Medicine and Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada; Department of Clinical Neurosciences, University of Calgary Cumming School of Medicine and Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada.
| | - Morris H Scantlebury
- Department of Pediatrics, University of Calgary Cumming School of Medicine and Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada; Department of Clinical Neurosciences, University of Calgary Cumming School of Medicine and Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| |
Collapse
|
40
|
Tipton MJ, Harper A, Paton JFR, Costello JT. The human ventilatory response to stress: rate or depth? J Physiol 2017. [PMID: 28650070 DOI: 10.1113/jp274596] [Citation(s) in RCA: 113] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Many stressors cause an increase in ventilation in humans. This is predominantly reported as an increase in minute ventilation (V̇E). But, the same V̇E can be achieved by a wide variety of changes in the depth (tidal volume, VT ) and number of breaths (respiratory frequency, ƒR ). This review investigates the impact of stressors including: cold, heat, hypoxia, pain and panic on the contributions of ƒR and VT to V̇E to see if they differ with different stressors. Where possible we also consider the potential mechanisms that underpin the responses identified, and propose mechanisms by which differences in ƒR and VT are mediated. Our aim being to consider if there is an overall differential control of ƒR and VT that applies in a wide range of conditions. We consider moderating factors, including exercise, sex, intensity and duration of stimuli. For the stressors reviewed, as the stress becomes extreme V̇E generally becomes increased more by ƒR than VT . We also present some tentative evidence that the pattern of ƒR and VT could provide some useful diagnostic information for a variety of clinical conditions. In The Physiological Society's year of 'Making Sense of Stress', this review has wide-ranging implications that are not limited to one discipline, but are integrative and relevant for physiology, psychophysiology, neuroscience and pathophysiology.
Collapse
Affiliation(s)
- Michael J Tipton
- Extreme Environments Laboratory, Department of Sport and Exercise Science, University of Portsmouth, Portsmouth, PO1 2ER, UK
| | - Abbi Harper
- Clinical Fellow in Intensive Care Medicine, Southmead Hospital, Bristol, BS10 5NB, UK
| | - Julian F R Paton
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences, University Walk, University of Bristol, Bristol, BS8 1TD, UK
| | - Joseph T Costello
- Extreme Environments Laboratory, Department of Sport and Exercise Science, University of Portsmouth, Portsmouth, PO1 2ER, UK
| |
Collapse
|
41
|
Xu Z, Tong S. Decompose the association between heatwave and mortality: Which type of heatwave is more detrimental? ENVIRONMENTAL RESEARCH 2017; 156:770-774. [PMID: 28494429 DOI: 10.1016/j.envres.2017.05.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 05/04/2017] [Accepted: 05/04/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND Heatwaves is the most hazardous natural disaster in Australia and its health impacts need to be well unveiled, but how to properly define a heatwave is still debatable. This study aimed to identify which type of heatwave is more detrimental to health and to elucidate which temperature indicator is more suitable for heatwave definition and early warning. METHODS We categorized temperature into extremely-hot and not-extremely-hot, and extremely-hot temperature refers to temperature at least ≥96th percentile of the monthly temperature distribution, and accordingly, heatwaves were categorized into four types: 1) Type I: extremely-hot days followed by extremely-hot nights (HWboth); 2) Type II: extremely-hot days followed by not-extremely-hot nights (HWday); 3) Type III: not-extremely-hot days followed by extremely-hot nights (HWnight); and 4) Type IV: not-extremely-hot days followed by not-extremely-hot nights (HWwarm). A Poisson regression allowing for over-dispersion was used to examine the relationship between different types of heatwaves and mortality in Sydney, Melbourne and Brisbane using the data from 1988 to 2011. RESULTS Mortality in Brisbane increased significantly during HWboth and HWwarm, and mortality in Melbourne increased significantly during HWboth and HWday. For Sydney, HWboth, HWwarm, and HWday were all associated with mortality increase, although no appreciable difference in the magnitudes of mortality increase among these three heatwave types was observed. HWnight was not associated with any significant mortality increase in these cities. Mean temperature is the best temperature indicator for heatwaves in Brisbane and maximum temperature is the best temperature indicator for heatwaves in Melbourne. CONCLUSIONS Extremely-hot days rather than extremely-hot nights played a critical role in heatwave-related mortality. City-specific heatwave early warning may be optimal for Australia.
Collapse
Affiliation(s)
- Zhiwei Xu
- School of Public Health and Social Work & Institute of Health and Biomedical Innovation, Queensland University of Technology, Australia.
| | - Shilu Tong
- School of Public Health and Social Work & Institute of Health and Biomedical Innovation, Queensland University of Technology, Australia
| |
Collapse
|
42
|
O'Lenick CR, Winquist A, Chang HH, Kramer MR, Mulholland JA, Grundstein A, Sarnat SE. Evaluation of individual and area-level factors as modifiers of the association between warm-season temperature and pediatric asthma morbidity in Atlanta, GA. ENVIRONMENTAL RESEARCH 2017; 156:132-144. [PMID: 28342349 PMCID: PMC5633283 DOI: 10.1016/j.envres.2017.03.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Revised: 03/11/2017] [Accepted: 03/13/2017] [Indexed: 05/19/2023]
Abstract
INTRODUCTION Previous studies have found associations between respiratory morbidity and high temperatures; however, few studies have explored associations in potentially sensitive sub-populations. METHODS We evaluated individual and area-level factors as modifiers of the association between warm-season (May-Sept.) temperature and pediatric respiratory morbidity in Atlanta. Emergency department (ED) visit data were obtained for children, 5-18 years old, with primary diagnoses of asthma or respiratory disease (diagnoses of upper respiratory infections, bronchiolitis, pneumonia, chronic obstructive pulmonary disease, asthma, or wheeze) in 20-county Atlanta during 1993-2012. Daily maximum temperature (Tmax) was acquired from the automated surface observing station at Atlanta Hartsfield International Airport. Poisson generalized linear models were used to estimate rate ratios (RR) between daily Tmax and asthma or respiratory disease ED visits, controlling for time and meteorology. Tmax effects were estimated for single-day lags of 0-6 days, for 3-, 5-, and 7-day moving averages and modeled with cubic terms to allow for non-linear relationships. Effect modification by individual factors (sex, race, insurance status) and area-level socioeconomic status (SES; ZIP code levels of poverty, education, and the neighborhood deprivation index) was examined via stratification. RESULTS Estimated RRs for Tmax and pediatric asthma ED visits were positive and significant for lag days 1-5, with the strongest single day association observed on lag day 2 (RR=1.06, 95% CI: 1.03, 1.09) for a change in Tmax from 27°C to 32°C (25th to 75th percentile). For the moving average exposure periods, associations increased as moving average periods increased. We observed stronger RRs between Tmax and asthma among males compared to females, non-white children compared to white children, children with private insurance compared to children with Medicaid, and among children living in high compared to low SES areas. Associations between Tmax and respiratory disease ED visits were weak and non-significant (p-value>0.05). CONCLUSIONS Results suggest socio-demographic factors (race/ethnicity, insurance status, and area-level SES) may confer vulnerability to temperature-related pediatric asthma morbidity. Our findings of weaker associations among children with Medicaid compared to other health insurance types and among children living in low compared to high SES areas run counter to our belief that children from disadvantaged households or ZIP codes would be more vulnerable to the respiratory effects of temperature. The potential reasons for these unexpected results are explored in the discussion.
Collapse
Affiliation(s)
- Cassandra R O'Lenick
- Department of Environmental Health, Rollins School of Public Health, Emory University, 1518 Clifton Road NE, Atlanta, GA 30322, USA.
| | - Andrea Winquist
- Department of Environmental Health, Rollins School of Public Health, Emory University, 1518 Clifton Road NE, Atlanta, GA 30322, USA.
| | - Howard H Chang
- Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, 1518 Clifton Road NE, Atlanta, GA 30322, USA.
| | - Michael R Kramer
- Department of Epidemiology, Rollins School of Public Health, Emory University, 1518 Clifton Road NE, Atlanta, GA 30322, USA.
| | - James A Mulholland
- School of Civil and Environmental Engineering, Georgia Institute of Technology, 790 Atlantic Drive NW, Atlanta, GA 30332 USA.
| | - Andrew Grundstein
- Department of Geography, University of Georgia, 210 Field St., Athens, GA 30602, USA.
| | - Stefanie Ebelt Sarnat
- Department of Environmental Health, Rollins School of Public Health, Emory University, 1518 Clifton Road NE, Atlanta, GA 30322, USA.
| |
Collapse
|
43
|
Izukura R, Imada H, Hashiguchi N, Sawatari H, Ohguri T, Miyazono M, Ohta S, Takakura C, Yamasaki K, Magota C, Fujita K, Kuroda H, Hirata H, Ohkusa T, Chishaki A. Cardiac and respiratory effects of deep regional hyperthermia using an 8 MHz radiofrequency-capacitive device on patients with cancer. Int J Hyperthermia 2017; 33:428-434. [PMID: 28093005 DOI: 10.1080/02656736.2017.1283064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
PURPOSE Hyperthermia (HT), an adjuvant therapy for variable cancers, may cause physiological changes in the patients, which may lead to cardiovascular problems. Among various HT treatments, the physiological effects of deep regional HT are still unclear. We examined the physiological alterations throughout deep regional HT to improve the HT safety. MATERIALS AND METHODS Thirty-one patients (age: 61 ± 12 years) with cancer received HT in the thoracic or upper abdominal regions using an 8-MHz radiofrequency-capacitive-device for 50 min. Rectal temperature (Trec), systolic and diastolic blood pressures (SBP and DBP), pulse rate (PR), respiratory rate (RR), percutaneous oxygen saturation (SpO2) and sweating volume were evaluated throughout HT. RESULTS At 50 min after starting HT, Trec, PR and RR were significantly increased compared with the baseline values (Trec: 38.2 ± 1.4 vs. 36.3 ± 0.8 °C, p < 0.001, PR: 104 ± 15 vs. 85 ± 16 bpm, p < 0.05, RR: 23 ± 3 vs. 21 ± 3/min, p < 0.05). Although the average SBP and DBP were both stable during HT in a recumbent position, these values dropped significantly in a standing position (SBP: 113 ± 16 vs. 127 ± 18 mmHg, p < 0.001, DBP: 70 ± 12 vs. 75 ± 13 mmHg, p < 0.01). The total amount of sweating was 356 ± 173 g/m2 on average. CONCLUSIONS Deep regional HT increased the deep body temperature and resulted in an increase of sweating with peripheral vasodilatation. Consequently, a significant reduction in BP would be induced on standing after HT. Careful attention is needed for patients receiving HT, especially when standing after HT.
Collapse
Affiliation(s)
- Rieko Izukura
- a Department of Health Sciences , Kyushu University Graduate School of Medical Sciences , Fukuoka , Japan
| | - Hajime Imada
- b Cancer Treatment Center , Tobata Kyoritsu Hospital , Kitakyushu , Japan
| | - Nobuko Hashiguchi
- a Department of Health Sciences , Kyushu University Graduate School of Medical Sciences , Fukuoka , Japan
| | - Hiroyuki Sawatari
- a Department of Health Sciences , Kyushu University Graduate School of Medical Sciences , Fukuoka , Japan
| | - Takayuki Ohguri
- c Department of Radiology , University of Occupational and Environmental Health , Kitakyushu , Japan
| | - Mami Miyazono
- d School of Nursing , Fukuoka Prefectural University , Fukuoka , Japan
| | - Shin Ohta
- b Cancer Treatment Center , Tobata Kyoritsu Hospital , Kitakyushu , Japan
| | - Chiduko Takakura
- b Cancer Treatment Center , Tobata Kyoritsu Hospital , Kitakyushu , Japan
| | - Keiko Yamasaki
- a Department of Health Sciences , Kyushu University Graduate School of Medical Sciences , Fukuoka , Japan
| | - Chie Magota
- a Department of Health Sciences , Kyushu University Graduate School of Medical Sciences , Fukuoka , Japan
| | - Kanae Fujita
- a Department of Health Sciences , Kyushu University Graduate School of Medical Sciences , Fukuoka , Japan
| | - Hiromi Kuroda
- a Department of Health Sciences , Kyushu University Graduate School of Medical Sciences , Fukuoka , Japan
| | - Hideki Hirata
- e Department of radiotherapy , St. Mary's Hospital , Kurume , Japan
| | - Tomoko Ohkusa
- f Sleep Apnea Center, Kyushu University Hospital , Fukuoka , Japan.,g Faculty of Health Sciences , Ube Frontier University , Yamaguchi , Japan
| | - Akiko Chishaki
- a Department of Health Sciences , Kyushu University Graduate School of Medical Sciences , Fukuoka , Japan
| |
Collapse
|
44
|
Bícego KC, Mortola JP. Thermal tachypnea in avian embryos. J Exp Biol 2017; 220:4634-4643. [DOI: 10.1242/jeb.171702] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 10/15/2017] [Indexed: 12/13/2022]
Abstract
Many adult mammals and birds respond to heat with thermal tachypnea, an increase in breathing frequency with shallow tidal volume, with minimal increase in oxygen consumption (V̇O2). This pattern favors heat dissipation by evaporative water loss (EWL) through the respiratory tract. We asked to what extent this response was apparent at the earliest stages of development, when pulmonary ventilation (V̇E) initiates. Measurements of V̇E(barometric technique), V̇O2(open-flow methodology) and EWL (water scrubbers) were performed on chicken embryos at the earliest appearance of V̇E, during the internal pipping stage. Data were collected, first, at the normal incubation temperature (37.5°C); then, ambient and egg temperatures were increased to approximately 44°C over a 2 h period. Other embryos of the same developmental stage (controls) were maintained in normothermia for the whole duration of the experiment. During heat exposure, the embryo's V̇O2 and carbon dioxide production increased little. In contrast, V̇E more than doubled (∼128% increase) entirely because of the large rise in breathing frequency (∼132% increase), with no change in tidal volume. EWL did not change significantly, probably because within the egg the thermal and water vapor gradients are almost non-existent. We conclude that chicken embryos respond to a major heat load with tachypnea, like many adult mammals and birds do. The appearance so early in development, although ineffective for heat loss, signifies that thermal tachypnea represents an important breathing response necessary to be functional since hatching.
Collapse
Affiliation(s)
- Kênia C. Bícego
- Department of Animal Morphology and Physiology, College of Agricultural and Veterinarian Sciences, São Paulo State University, Jaboticabal, SP, Brazil
- National Institute of Science and Technology on Comparative Physiology (INCT- Fisiologia Comparada), Brazil
| | | |
Collapse
|
45
|
Barrett KT, Wilson RJA, Scantlebury MH. TRPV1 deletion exacerbates hyperthermic seizures in an age-dependent manner in mice. Epilepsy Res 2016; 128:27-34. [PMID: 27810513 DOI: 10.1016/j.eplepsyres.2016.10.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 09/07/2016] [Accepted: 10/24/2016] [Indexed: 01/19/2023]
Abstract
Febrile seizures (FS) are the most common seizure disorder to affect children. Although there is mounting evidence to support that FS occur when children have fever-induced hyperventilation leading to respiratory alkalosis, the underlying mechanisms of hyperthermia-induced hyperventilation and links to FS remain poorly understood. As transient receptor potential vanilloid-1 (TRPV1) receptors are heat-sensitive, play an important role in adult thermoregulation and modulate respiratory chemoreceptors, we hypothesize that TRPV1 activation is important for hyperthermia-induced hyperventilation leading to respiratory alkalosis and decreased FS thresholds, and consequently, TRPV1 KO mice will be relatively protected from hyperthermic seizures. To test our hypothesis we subjected postnatal (P) day 8-20 TRPV1 KO and C57BL/6 control mice to heated dry air. Seizure threshold temperature, latency and the rate of rise of body temperature during hyperthermia were assessed. At ages where differences in seizure thresholds were identified, head-out plethysmography was used to assess breathing and the rate of expired CO2 in response to hyperthermia, to determine if the changes in seizure thresholds were related to respiratory alkalosis. Paradoxically, we observed a pro-convulsant effect of TRPV1 deletion (∼4min decrease in seizure latency), and increased ventilation in response to hyperthermia in TRPV1 KO compared to control mice at P20. This pro-convulsant effect of TRPV1 absence was not associated with an increased rate of expired CO2, however, these mice had a more rapid rise in body temperature following exposure to hyperthermia than controls, and the expected linear relationship between body weight and seizure latency was absent. Based on these findings, we conclude that deletion of the TRPV1 receptor prevents reduction in hyperthermic seizure susceptibility in older mouse pups, via a mechanism that is independent of hyperthermia-induced respiratory alkalosis, but possibly involves impaired development of thermoregulatory mechanisms, although at present the mechanism remain unknown.
Collapse
Affiliation(s)
- Karlene T Barrett
- Department of Pediatrics, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada; Alberta Children's Hospital Research Institute, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada
| | - Richard J A Wilson
- Alberta Children's Hospital Research Institute, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada; Department of Physiology and Pharmacology, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada; Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada
| | - Morris H Scantlebury
- Department of Pediatrics, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada; Alberta Children's Hospital Research Institute, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada; Department of Clinical Neuroscience, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada.
| |
Collapse
|
46
|
McDonald FB, Chandrasekharan K, Wilson RJA, Hasan SU. Interactive effects of maternal cigarette smoke, heat stress, hypoxia, and lipopolysaccharide on neonatal cardiorespiratory and cytokine responses. Am J Physiol Regul Integr Comp Physiol 2016; 311:R1113-R1124. [PMID: 27733384 DOI: 10.1152/ajpregu.00062.2016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 10/03/2016] [Accepted: 10/06/2016] [Indexed: 11/22/2022]
Abstract
Maternal cigarette smoke (CS) exposure exhibits a strong epidemiological association with Sudden Infant Death Syndrome, but other environmental stressors, including infection, hyperthermia, and hypoxia, have also been postulated as important risk factors. This study examines whether maternal CS exposure causes maladaptations within homeostatic control networks by influencing the response to lipopolysaccharide, heat stress, and/or hypoxia in neonatal rats. Pregnant dams were exposed to CS or parallel sham treatments daily for the length of gestation. Offspring were studied at postnatal days 6-8 at ambient temperatures (Ta) of 33°C or 38°C. Within each group, rats were allocated to control, saline, or LPS (200 µg/kg) treatments. Cardiorespiratory patterns were examined using head-out plethysmography and ECG surface electrodes during normoxia and hypoxia (10% O2). Serum cytokine concentrations were quantified from samples taken at the end of each experiment. Our results suggest maternal CS exposure does not alter minute ventilation (V̇e) or heart rate (HR) response to infection or high temperature, but independently increases apnea frequency. CS also primes the inflammatory system to elicit a stronger cytokine response to bacterial insult. High Ta independently depresses V̇e but augments the hypoxia-induced increase in V̇e Moreover, higher Ta increases HR during normoxia and hypoxia, and in the presence of an immune challenge, increases HR during normoxia, and reduces the increase normally associated with hypoxia. Thus, while most environmental risk factors increase the burden on the cardiorespiratory system in early life, hyperthermia and infection blunt the normal HR response to hypoxia, and gestational CS independently destabilizes breathing by increasing apneas.
Collapse
Affiliation(s)
- Fiona B McDonald
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, Faculty of Medicine, University of Calgary, Alberta, Canada; and
| | - Kumaran Chandrasekharan
- Section of Neonatal-Perinatal Medicine, Department of Pediatrics, Faculty of Medicine, Health Sciences Centre, University of Calgary, Alberta, Canada
| | - Richard J A Wilson
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, Faculty of Medicine, University of Calgary, Alberta, Canada; and
| | - Shabih U Hasan
- Section of Neonatal-Perinatal Medicine, Department of Pediatrics, Faculty of Medicine, Health Sciences Centre, University of Calgary, Alberta, Canada
| |
Collapse
|
47
|
Sarnat HB, Flores-Sarnat L. Synaptogenesis and Myelination in the Nucleus/Tractus Solitarius: Potential Role in Apnea of Prematurity, Congenital Central Hypoventilation, and Sudden Infant Death Syndrome. J Child Neurol 2016; 31:722-32. [PMID: 26661483 DOI: 10.1177/0883073815615227] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 09/26/2015] [Indexed: 12/14/2022]
Abstract
Fetuses as early as 15 weeks' gestation exhibit rhythmical respiratory movements shown by real-time ultrasonography. The nucleus/tractus solitarius is the principal brainstem respiratory center; other medullary nuclei also participate. The purpose was to determine temporal maturation of synaptogenesis. Delayed synaptic maturation may explain neurogenic apnea or hypoventilation of prematurity and some cases of sudden infant death syndrome. Sections of medulla oblongata were studied from 30 human fetal and neonatal brains 9 to 41 weeks' gestation. Synaptophysin demonstrated the immunocytochemical sequence of synaptogenesis. Other neuronal markers and myelin stain also were applied. The nucleus/tractus solitarius was similarly studied in fetuses with chromosomopathies, metabolic encephalopathies, and brain malformations. Synapse formation in the nucleus solitarius begins at about 12 weeks' gestation and matures by 15 weeks; myelination initiated at 33 weeks. Synaptogenesis was delayed in 3 fetuses with different conditions, but was not specific for only nucleus solitarius. Delayed synaptogenesis or myelination in the nucleus solitarius may play a role in neonatal hypoventilation, especially in preterm infants and in some sudden infant death syndrome cases.
Collapse
Affiliation(s)
- Harvey B Sarnat
- Departments of Paediatrics, Pathology (Neuropathology) and Clinical Neurosciences, University of Calgary and Alberta Children's Hospital Research Institute, Calgary Alberta, Canada
| | - Laura Flores-Sarnat
- Departments of Paediatrics, Pathology (Neuropathology) and Clinical Neurosciences, University of Calgary and Alberta Children's Hospital Research Institute, Calgary Alberta, Canada
| |
Collapse
|
48
|
Bain AR, Nybo L, Ainslie PN. Cerebral Vascular Control and Metabolism in Heat Stress. Compr Physiol 2016; 5:1345-80. [PMID: 26140721 DOI: 10.1002/cphy.c140066] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This review provides an in-depth update on the impact of heat stress on cerebrovascular functioning. The regulation of cerebral temperature, blood flow, and metabolism are discussed. We further provide an overview of vascular permeability, the neurocognitive changes, and the key clinical implications and pathologies known to confound cerebral functioning during hyperthermia. A reduction in cerebral blood flow (CBF), derived primarily from a respiratory-induced alkalosis, underscores the cerebrovascular changes to hyperthermia. Arterial pressures may also become compromised because of reduced peripheral resistance secondary to skin vasodilatation. Therefore, when hyperthermia is combined with conditions that increase cardiovascular strain, for example, orthostasis or dehydration, the inability to preserve cerebral perfusion pressure further reduces CBF. A reduced cerebral perfusion pressure is in turn the primary mechanism for impaired tolerance to orthostatic challenges. Any reduction in CBF attenuates the brain's convective heat loss, while the hyperthermic-induced increase in metabolic rate increases the cerebral heat gain. This paradoxical uncoupling of CBF to metabolism increases brain temperature, and potentiates a condition whereby cerebral oxygenation may be compromised. With levels of experimentally viable passive hyperthermia (up to 39.5-40.0 °C core temperature), the associated reduction in CBF (∼ 30%) and increase in cerebral metabolic demand (∼ 10%) is likely compensated by increases in cerebral oxygen extraction. However, severe increases in whole-body and brain temperature may increase blood-brain barrier permeability, potentially leading to cerebral vasogenic edema. The cerebrovascular challenges associated with hyperthermia are of paramount importance for populations with compromised thermoregulatory control--for example, spinal cord injury, elderly, and those with preexisting cardiovascular diseases.
Collapse
Affiliation(s)
- Anthony R Bain
- Centre for Heart Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Okanagan Campus, Kelowna, Canada
| | - Lars Nybo
- Department of Nutrition, Exercise and Sport Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Philip N Ainslie
- Centre for Heart Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Okanagan Campus, Kelowna, Canada
| |
Collapse
|
49
|
Bunker A, Wildenhain J, Vandenbergh A, Henschke N, Rocklöv J, Hajat S, Sauerborn R. Effects of Air Temperature on Climate-Sensitive Mortality and Morbidity Outcomes in the Elderly; a Systematic Review and Meta-analysis of Epidemiological Evidence. EBioMedicine 2016; 6:258-268. [PMID: 27211569 PMCID: PMC4856745 DOI: 10.1016/j.ebiom.2016.02.034] [Citation(s) in RCA: 258] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Revised: 02/09/2016] [Accepted: 02/18/2016] [Indexed: 11/03/2022] Open
Abstract
INTRODUCTION Climate change and rapid population ageing are significant public health challenges. Understanding which health problems are affected by temperature is important for preventing heat and cold-related deaths and illnesses, particularly in the elderly. Here we present a systematic review and meta-analysis on the effects of ambient hot and cold temperature (excluding heat/cold wave only studies) on elderly (65+ years) mortality and morbidity. METHODS Time-series or case-crossover studies comprising cause-specific cases of elderly mortality (n=3,933,398) or morbidity (n=12,157,782) were pooled to obtain a percent change (%) in risk for temperature exposure on cause-specific disease outcomes using a random-effects meta-analysis. RESULTS A 1°C temperature rise increased cardiovascular (3.44%, 95% CI 3.10-3.78), respiratory (3.60%, 3.18-4.02), and cerebrovascular (1.40%, 0.06-2.75) mortality. A 1°C temperature reduction increased respiratory (2.90%, 1.84-3.97) and cardiovascular (1.66%, 1.19-2.14) mortality. The greatest risk was associated with cold-induced pneumonia (6.89%, 20-12.99) and respiratory morbidity (4.93% 1.54-8.44). A 1°C temperature rise increased cardiovascular, respiratory, diabetes mellitus, genitourinary, infectious disease and heat-related morbidity. DISCUSSION Elevated risks for the elderly were prominent for temperature-induced cerebrovascular, cardiovascular, diabetes, genitourinary, infectious disease, heat-related, and respiratory outcomes. These risks will likely increase with climate change and global ageing.
Collapse
Affiliation(s)
- Aditi Bunker
- Network Aging Research, University of Heidelberg, Bergheimer Strasse 20, D-69115 Heidelberg, Germany; Institute of Public Health, University of Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany.
| | - Jan Wildenhain
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Kings Buildings, Edinburgh, Midlothian, United Kingdom
| | - Alina Vandenbergh
- Network Aging Research, University of Heidelberg, Bergheimer Strasse 20, D-69115 Heidelberg, Germany; Institute of Public Health, University of Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Nicholas Henschke
- Institute of Public Health, University of Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Joacim Rocklöv
- Department of Public Health and Clinical Medicine, Epidemiology and Global Health, Umeå University, 901 87 Umeå, Sweden
| | - Shakoor Hajat
- London School of Hygiene and Tropical Medicine, 15-17 Tavistock Place, London WC1H 9SH, United Kingdom
| | - Rainer Sauerborn
- Institute of Public Health, University of Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| |
Collapse
|
50
|
Tsuji B, Hayashi K, Kondo N, Nishiyasu T. Characteristics of hyperthermia-induced hyperventilation in humans. Temperature (Austin) 2016; 3:146-60. [PMID: 27227102 PMCID: PMC4879782 DOI: 10.1080/23328940.2016.1143760] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 01/14/2016] [Accepted: 01/14/2016] [Indexed: 11/11/2022] Open
Abstract
In humans, hyperthermia leads to activation of a set of thermoregulatory responses that includes cutaneous vasodilation and sweating. Hyperthermia also increases ventilation in humans, as is observed in panting dogs, but the physiological significance and characteristics of the hyperventilatory response in humans remain unclear. The relative contribution of respiratory heat loss to total heat loss in a hot environment in humans is small, and this hyperventilation causes a concomitant reduction in arterial CO2 pressure (hypocapnia), which can cause cerebral hypoperfusion. Consequently, hyperventilation in humans may not contribute to the maintenance of physiological homeostasis (i.e., thermoregulation). To gain some insight into the physiological significance of hyperthermia-induced hyperventilation in humans, in this review, we discuss 1) the mechanisms underlying hyperthermia-induced hyperventilation, 2) the factors modulating this response, and 3) the physiological consequences of the response.
Collapse
Affiliation(s)
- Bun Tsuji
- Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba City, Japan; Department of Health Sciences, Prefectural University of Hiroshima, Hiroshima, Japan
| | - Keiji Hayashi
- Junior College, University of Shizuoka , Shizuoka, Japan
| | - Narihiko Kondo
- Faculty of Human Development, Kobe University , Kobe, Japan
| | - Takeshi Nishiyasu
- Institute of Health and Sport Sciences, University of Tsukuba , Tsukuba City, Japan
| |
Collapse
|