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Cherif M, Brose U, Hirt MR, Ryser R, Silve V, Albert G, Arnott R, Berti E, Cirtwill A, Dyer A, Gauzens B, Gupta A, Ho HC, Portalier SMJ, Wain D, Wootton K. The environment to the rescue: can physics help predict predator-prey interactions? Biol Rev Camb Philos Soc 2024. [PMID: 38855988 DOI: 10.1111/brv.13105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 05/17/2024] [Accepted: 05/24/2024] [Indexed: 06/11/2024]
Abstract
Understanding the factors that determine the occurrence and strength of ecological interactions under specific abiotic and biotic conditions is fundamental since many aspects of ecological community stability and ecosystem functioning depend on patterns of interactions among species. Current approaches to mapping food webs are mostly based on traits, expert knowledge, experiments, and/or statistical inference. However, they do not offer clear mechanisms explaining how trophic interactions are affected by the interplay between organism characteristics and aspects of the physical environment, such as temperature, light intensity or viscosity. Hence, they cannot yet predict accurately how local food webs will respond to anthropogenic pressures, notably to climate change and species invasions. Herein, we propose a framework that synthesises recent developments in food-web theory, integrating body size and metabolism with the physical properties of ecosystems. We advocate for combination of the movement paradigm with a modular definition of the predation sequence, because movement is central to predator-prey interactions, and a generic, modular model is needed to describe all the possible variation in predator-prey interactions. Pending sufficient empirical and theoretical knowledge, our framework will help predict the food-web impacts of well-studied physical factors, such as temperature and oxygen availability, as well as less commonly considered variables such as wind, turbidity or electrical conductivity. An improved predictive capability will facilitate a better understanding of ecosystem responses to a changing world.
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Affiliation(s)
- Mehdi Cherif
- Aquatic Ecosystems and Global Change Research Unit, National Research Institute for Agriculture Food and the Environment, 50 avenue de Verdun, Cestas Cedex, 33612, France
| | - Ulrich Brose
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstrasse 4, Leipzig, 04103, Germany
- Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Straße 159, Jena, 07743, Germany
| | - Myriam R Hirt
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstrasse 4, Leipzig, 04103, Germany
- Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Straße 159, Jena, 07743, Germany
| | - Remo Ryser
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstrasse 4, Leipzig, 04103, Germany
- Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Straße 159, Jena, 07743, Germany
| | - Violette Silve
- Aquatic Ecosystems and Global Change Research Unit, National Research Institute for Agriculture Food and the Environment, 50 avenue de Verdun, Cestas Cedex, 33612, France
| | - Georg Albert
- Department of Forest Nature Conservation, Georg-August-Universität, Büsgenweg 3, Göttingen, 37077, Germany
| | - Russell Arnott
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge, Cambridgeshire, CB2 1LR, UK
| | - Emilio Berti
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstrasse 4, Leipzig, 04103, Germany
- Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Straße 159, Jena, 07743, Germany
| | - Alyssa Cirtwill
- Spatial Foodweb Ecology Group, Research Centre for Ecological Change (REC), Faculty of Biological and Environmental Sciences, University of Helsinki, P.O. Box 4 (Yliopistonkatu 3), Helsinki, 00014, Finland
| | - Alexander Dyer
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstrasse 4, Leipzig, 04103, Germany
- Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Straße 159, Jena, 07743, Germany
| | - Benoit Gauzens
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstrasse 4, Leipzig, 04103, Germany
- Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Straße 159, Jena, 07743, Germany
| | - Anhubav Gupta
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, Zürich, 8057, Switzerland
| | - Hsi-Cheng Ho
- Institute of Ecology and Evolutionary Biology, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd, Taipei, 106, Taiwan
| | - Sébastien M J Portalier
- Department of Mathematics and Statistics, University of Ottawa, STEM Complex, room 342, 150 Louis-Pasteur Pvt, Ottawa, Ontario, K1N 6N5, Canada
| | - Danielle Wain
- 7 Lakes Alliance, Belgrade Lakes, 137 Main St, Belgrade Lakes, ME, 04918, USA
| | - Kate Wootton
- School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand
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Moyen NE, Ediger TR, Taylor KM, Hancock EG, Holden LD, Tracy EE, Kay PH, Irick CR, Kotzen KJ, He DD. Sleeping for One Week on a Temperature-Controlled Mattress Cover Improves Sleep and Cardiovascular Recovery. Bioengineering (Basel) 2024; 11:352. [PMID: 38671774 PMCID: PMC11048088 DOI: 10.3390/bioengineering11040352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 03/19/2024] [Accepted: 03/31/2024] [Indexed: 04/28/2024] Open
Abstract
Body temperature should be tightly regulated for optimal sleep. However, various extrinsic and intrinsic factors can alter body temperature during sleep. In a free-living study, we examined how sleep and cardiovascular health metrics were affected by sleeping for one week with (Pod ON) vs. without (Pod OFF), an active temperature-controlled mattress cover (the Eight Sleep Pod). A total of 54 subjects wore a home sleep test device (HST) for eight nights: four nights each with Pod ON and OFF (>300 total HST nights). Nightly sleeping heart rate (HR) and heart rate variability (HRV) were collected. Compared to Pod OFF, men and women sleeping at cooler temperatures in the first half of the night significantly improved deep (+14 min; +22% mean change; p = 0.003) and REM (+9 min; +25% mean change; p = 0.033) sleep, respectively. Men sleeping at warm temperatures in the second half of the night significantly improved light sleep (+23 min; +19% mean change; p = 0.023). Overall, sleeping HR (-2% mean change) and HRV (+7% mean change) significantly improved with Pod ON (p < 0.01). To our knowledge, this is the first study to show a continuously temperature-regulated bed surface can (1) significantly modify time spent in specific sleep stages in certain parts of the night, and (2) enhance cardiovascular recovery during sleep.
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Buguet A, Radomski MW, Reis J, Spencer PS. Heatwaves and human sleep: Stress response versus adaptation. J Neurol Sci 2023; 454:120862. [PMID: 37922826 DOI: 10.1016/j.jns.2023.120862] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 09/21/2023] [Accepted: 10/27/2023] [Indexed: 11/07/2023]
Abstract
The World Meteorological Organization considers a heatwave as "a period of statistically unusual hot weather persisting for a number of days and nights". Accompanying the ongoing global climate change, sharp heatwave bouts occur worldwide, growing in frequency and intensity, and beginning earlier in the season. Heatwaves exacerbate the risk of heat-related illnesses, hence human morbidity and mortality, particularly in vulnerable elderly and children. Heat-related illnesses present a continuum from normothermic (prickly heat, heat edema, heat cramps, heat tetany) to hyperthermic syndromes (from heat syncope and heat exhaustion to lethal heat stroke). Heat stroke may occur through passive heating and/or exertional exercise. "Normal sleep", such as observed in temperate conditions, is altered during heatwaves. Brisk excessive heat bouts shorten and fragment human sleep. Particularly, deep N3 sleep (formerly slow-wave sleep) and REM sleep are depleted, such as in other stressful situations. The resultant sleep loss is deleterious to cognitive performance, emotional brain function, behavior, and susceptibility to chronic health conditions and infectious diseases. Our group has previously demonstrated that sleep constitutes an adaptive mechanism during climatic heat acclimatization. In parallel, artificial heat acclimation procedures have been proposed in sports and military activities, and for the elderly. Other preventive actions should be considered, such as education and urban heat island cooling (vegetation, white paint), thus avoiding energy-hungry air conditioning.
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Affiliation(s)
- Alain Buguet
- Invited Scientist, Malaria Research Unit, UMR 5246 CNRS, Claude-Bernard Lyon-1 University, 69622 Villeurbanne, France.
| | - Manny W Radomski
- Professor Emeritus at the University of Toronto, Apt n° 2501, 2010 Islington Avenue, Toronto, ON M9P3S8, Canada
| | - Jacques Reis
- University of Strasbourg, 67000 Strasbourg, France; Association RISE, 3 rue du Loir, 67205 Oberhausbergen, France
| | - Peter S Spencer
- Department of Neurology, School of Medicine, Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR 97239, USA.
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Gao L, Zheng X, Baker SN, Li P, Scheer FAJL, Nogueira RC, Hu K. Associations of rest-activity rhythm disturbances with stroke risk and post-stroke adverse outcomes. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.05.14.23289966. [PMID: 37292791 PMCID: PMC10246053 DOI: 10.1101/2023.05.14.23289966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Background Almost all biological and disease processes are influenced by circadian clocks and display ∼24-hour rhythms. Disruption of these rhythms may be an important novel risk factor for stroke. We evaluated the association between 24-h rest-activity rhythm measures, stroke risk, and major post-stroke adverse outcomes. Methods In this cohort study, we examined ∼100,000 participants in the UK Biobank (44-79 years old; ∼57% females) who underwent an actigraphy (6-7 days) and 5-year median follow-up. We derived: (1) most active 10 hours activity counts ( M10 ) across the 24-h cycle and the timing of its midpoint ( M10 midpoint ); (2) the least active 5 hours counts ( L5 ) and its midpoint timing ( L5 midpoint ); (3) relative amplitude ( RA ) - (M10-L5)/(M10+L5); (4) interdaily stability (IS): stability and (5) intradaily variability (IV), fragmentation of the rhythm. Cox proportional hazard models were constructed for time to (i) incident stroke (n=1,652); and (ii) post-stroke adverse outcomes (dementia, depression, disability, or death). Results Suppressed RA (lower M10 and higher L5) was associated with stroke risk after adjusting for demographics; the risk was highest in the lowest quartile [Q1] for RA (HR=1.62; 95% CI:1.36-1.93, p <0.001) compared to the top quartile [Q4]. Participants with later M10 midpoint timing (14:00-15:26, HR=1.26, CI:1.07-1.49, p =0.007) also had a higher risk for stroke than earlier (12:17-13:10) participants. A fragmented rhythm (IV) was also associated with a higher risk for stroke (Q4 vs. Q1; HR=1.27; CI:1.06-1.50, p =0.008), but differences in the stability of rhythms (IS) were not. Suppressed RA was associated with an increased risk of unfavorable post-stroke outcomes (Q1 vs. Q4; 1.78 [1.29-2.47]; p <0.001). All the associations were independent of age, sex, race, obesity, sleep disorders, cardiovascular diseases or risks, and other morbidity burdens. Conclusion Suppressed 24-h rest-activity rhythm may be a risk factor for stroke and an early indicator of major post-stroke adverse outcomes.
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Bhardwaj S, Singh S, Ganguly I, Bhatia AK, Dixit SP. Deciphering local adaptation of native Indian cattle ( Bos indicus) breeds using landscape genomics and in-silico prediction of deleterious SNP effects on protein structure and function. 3 Biotech 2023; 13:86. [PMID: 36816754 PMCID: PMC9931982 DOI: 10.1007/s13205-023-03493-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 01/25/2023] [Indexed: 02/19/2023] Open
Abstract
India has 50 registered breeds of native cattle (Bos indicus) which are locally adapted to diverse environmental conditions. This study aimed to investigate the genomic basis of adaptation of native Indian cattle and to predict the impact of key SNPs on the amino acid changes that affect protein function. The Illumina 777 K BovineHD BeadChip was used to genotype 178 native cattle belonging to contrasting landscapes and agro-climatic conditions. The genotype-environment association was investigated with R. SamBada, using 5,74,382 QC passed SNPs and 11 predictor variables (10 multi-collinearity controlled environmental variables and 1 variable as "score of PCA" on ancestry coefficients of individuals). In total, 1,12,780 models were selected as significant (q < 0.05) based on G score. The pathway ontology of the annotated genes revealed many important pathways and genes having a direct and indirect role in cold and hot adaptation. Only ten SNP variants had a SIFT score of < 0.05 (deleterious), and only two of them, each lying in the genes CRYBA1 and USP18, were predicted to be deleterious with high confidence. RaptorX predicted the tertiary structures of proteins encoded by wild and mutant variants of these genes. The quality of the models was determined using Ramachandran plots and RaptorX parameters, indicating that they are accurate. RaptorX and I-Mutant 2.0 softwares revealed significant differences among wild and mutant proteins. Adaptive alleles identified in the present investigation might be responsible for the local adaptation of these cattle breeds. Supplementary Information The online version contains supplementary material available at 10.1007/s13205-023-03493-3.
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Affiliation(s)
- Shivam Bhardwaj
- Animal Genetics and Breeding Division, ICAR-National Dairy Research Institute, Karnal, 132001 India
| | - Sanjeev Singh
- Animal Genetics Division, ICAR-National Bureau of Animal Genetic Resources, Karnal, Haryana 132001 India
| | - Indrajit Ganguly
- Animal Genetics Division, ICAR-National Bureau of Animal Genetic Resources, Karnal, Haryana 132001 India
| | - Avnish Kumar Bhatia
- Animal Genetics Division, ICAR-National Bureau of Animal Genetic Resources, Karnal, Haryana 132001 India
| | - S. P. Dixit
- Animal Genetics Division, ICAR-National Bureau of Animal Genetic Resources, Karnal, Haryana 132001 India
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Circadian patterns of heart rate, respiratory rate and skin temperature in hospitalized COVID-19 patients. PLoS One 2022; 17:e0268065. [PMID: 35797369 PMCID: PMC9262173 DOI: 10.1371/journal.pone.0268065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 04/22/2022] [Indexed: 12/15/2022] Open
Abstract
Rationale
Vital signs follow circadian patterns in both healthy volunteers and critically ill patients, which seem to be influenced by disease severity in the latter. In this study we explored the existence of circadian patterns in heart rate, respiratory rate and skin temperature of hospitalized COVID-19 patients, and aimed to explore differences in circadian rhythm amplitude during patient deterioration.
Methods
We performed a retrospective study of COVID-19 patients admitted to the general ward of a tertiary hospital between April 2020 and March 2021. Patients were continuously monitored using a wireless sensor and fingertip pulse oximeter. Data was divided into three cohorts: patients who recovered, patients who developed respiratory insufficiency and patients who died. For each cohort, a population mean cosinor model was fitted to detect rhythmicity. To assess changes in amplitude, a mixed-effect cosinor model was fitted.
Results
A total of 429 patients were monitored. Rhythmicity was observed in heartrate for the recovery cohort (p<0.001), respiratory insufficiency cohort (p<0.001 and mortality cohort (p = 0.002). Respiratory rate showed rhythmicity in the recovery cohort (p<0.001), but not in the other cohorts (p = 0.18 and p = 0.51). Skin temperature also showed rhythmicity in the recovery cohort (p<0.001), but not in the other cohorts (p = 0.22 and p = 0.12). For respiratory insufficiency, only the amplitude of heart rate circadian pattern increased slightly the day before (1.2 (99%CI 0.16–2.2, p = 0.002)). In the mortality cohort, the amplitude of heart rate decreased (-1.5 (99%CI -2.6- -0.42, p<0.001)) and respiratory rate amplitude increased (0.72 (99%CI 0.27–1.3, p = 0.002) the days before death.
Conclusion
A circadian rhythm is present in heart rate of COVID-19 patients admitted to the general ward. For respiratory rate and skin temperature, rhythmicity was only found in patients who recover, but not in patients developing respiratory insufficiency or death. We found no consistent changes in circadian rhythm amplitude accompanying patient deterioration.
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Min KB, Lee S, Min JY. High and low ambient temperature at night and the prescription of hypnotics. Sleep 2021; 44:6016156. [PMID: 33442740 DOI: 10.1093/sleep/zsaa262] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 10/04/2020] [Indexed: 11/14/2022] Open
Abstract
STUDY OBJECTIVES This study investigated the association between ambient nighttime temperature and sleep problems assessed by the prescription dose of sleeping pills in South Korean adults. METHODS We used the 2002-2015 National Health Insurance Service-National Sample Cohort. A total of 711,079 adults who were 20 years old or older were included, wherein 42,858 adults (~6%) had been prescribed hypnotic medications including zolpidem (N05CF02) and triazolam (N05CD05). Ambient temperature data was calculated as the mean highest temperature of nighttime (23:00-07:00) for every month from January to December. We combined the drug-prescribed date with the administrative districts-level daily nighttime temperature between 2002 and 2015. RESULTS We found that a non-linear, U-shaped relationship between nighttime temperature and hypnotic medication prescription. With an increase per 1°C temperature or an increase in a square per 1°C, the prescription dose of sleeping pills was significantly increased (both p < 0.05). At each 5°C nighttime temperature, subjects belonging to low (≤0°C and 0-5°C) or high (20-25°C and ≥25°C) temperature categories had significantly higher doses of sleeping pills than those at the reference temperature (10-15°C). Changes in nighttime temperature had a significant non-linear effect on the prescribed dosage of hypnotic medications for both adults (p < 0.0001) and the elderly (p = 0.0006). CONCLUSION We found that either a high or low nighttime temperature was significantly associated with a high daily dose of hypnotic medications in the Korean population.
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Affiliation(s)
- Kyoung-Bok Min
- Department of Preventive Medicine, College of Medicine, Seoul National University, Seoul, Republic of Korea
| | - Sohyae Lee
- Department of Preventive Medicine, College of Medicine, Seoul National University, Seoul, Republic of Korea
| | - Jin-Young Min
- Veterans Medical Research Institute, Veterans Health Service Medical Center, Seoul, Republic of Korea
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Lorenz N, Spada J, Sander C, Riedel-Heller SG, Hegerl U. Circadian skin temperature rhythms, circadian activity rhythms and sleep in individuals with self-reported depressive symptoms. J Psychiatr Res 2019; 117:38-44. [PMID: 31279242 DOI: 10.1016/j.jpsychires.2019.06.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 06/25/2019] [Accepted: 06/28/2019] [Indexed: 11/19/2022]
Abstract
BACKGROUND Disturbed circadian rhythms have been associated with depression. New body-worn devices allow the objective recording of circadian parameters such as physical activity, skin temperature and sleep. The objective of this study was to investigate whether circadian skin temperature and circadian activity rhythms are altered in depressed individuals. METHODS Data on skin temperature, physical activity and sleep were available for 1610 subjects from a population-based cohort study. In a matching process two groups were formed for analysis: 121 participants with pronounced depression symptoms (CES-D Score > 21) and n = 121 matched non-depressed controls (CES-D Score < 15). Circadian rhythms were investigated by analyzing non-parametric rhythm indicators of 24-h skin temperature and physical activity data. Sleep timing, continuity and quantity were calculated from actigraphy. RESULTS No differences between the groups were found when all participants were considered. After excluding antidepressant medicated participants, the depression group was found to have a lower skin temperature amplitude t(208) = 2.45, p = .015 and a less stable skin temperature rhythm t(208) = 2.40, p = .017. The amplitude predicted the group status (beta = -5.529, p = .016). No effects were found for activity or sleep. CONCLUSION The results indicate that skin-temperature rhythms are blunted in unmedicated depressed individuals. This could be a promising non-invasive marker for further analysis.
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Affiliation(s)
- Noah Lorenz
- Medical Faculty, Department of Psychiatry and Psychotherapy, University Leipzig, Leipzig, DE, Germany; Research Centre of the German Depression Foundation, Leipzig, DE, Germany.
| | - Janek Spada
- University of Leipzig, Department of Psychology, Leipzig, DE, Germany
| | - Christian Sander
- Medical Faculty, Department of Psychiatry and Psychotherapy, University Leipzig, Leipzig, DE, Germany; Research Centre of the German Depression Foundation, Leipzig, DE, Germany
| | - Steffie G Riedel-Heller
- University of Leipzig, Institute of Social Medicine, Occupational Health and Public Health, Leipzig, DE, Germany
| | - Ulrich Hegerl
- Research Centre of the German Depression Foundation, Leipzig, DE, Germany; Department of Psychiatry, Psychosomatics and Psychotherapie, Goethe-University, Frankfurt, Germany
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Nguyen K, Stahlschmidt Z. When to fight? Disentangling temperature and circadian effects on aggression and agonistic contests. Anim Behav 2019. [DOI: 10.1016/j.anbehav.2018.11.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Te Lindert BHW, Van Someren EJW. Skin temperature, sleep, and vigilance. HANDBOOK OF CLINICAL NEUROLOGY 2018; 156:353-365. [PMID: 30454600 DOI: 10.1016/b978-0-444-63912-7.00021-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A large number of studies have shown a close association between the 24-hour rhythms in core body temperature and sleep propensity. More recently, studies have have begun to elucidate an intriguing association of sleep with skin temperature as well. The present chapter addresses the association of sleep and alertness with skin temperature. It discusses whether the association could reflect common underlying drivers of both sleep propensity and skin vasodilation; whether it could reflect efferents of sleep-regulating brain circuits to thermoregulatory circuits; and whether skin temperature could provide afferent input to sleep-regulating brain circuits. Sleep regulation and concomitant changes in skin temperature are systematically discussed and three parallel factors suggested: a circadian clock mechanism, a homeostatic hourglass mechanism, and a third set of sleep-permissive and wake-promoting factors that gate the effectiveness of signals from the clock and hourglass in the actual induction of sleep or maintenance of alert wakefulness. The chapter moreover discusses how the association between skin temperature and arousal can change with sleep deprivation and insomnia. Finally it addresses whether the promising laboratory findings on the effects of skin temperature manipulations on vigilance can be applied to improve sleep in everyday life.
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Affiliation(s)
- Bart H W Te Lindert
- Department of Sleep and Cognition, Netherlands Institute for Neuroscience, Amsterdam, The Netherlands
| | - Eus J W Van Someren
- Department of Sleep and Cognition, Netherlands Institute for Neuroscience, Amsterdam, The Netherlands; Departments of Psychiatry and Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam UMC, Amsterdam, The Netherlands.
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Obradovich N, Migliorini R, Mednick SC, Fowler JH. Nighttime temperature and human sleep loss in a changing climate. SCIENCE ADVANCES 2017; 3:e1601555. [PMID: 28560320 PMCID: PMC5446217 DOI: 10.1126/sciadv.1601555] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 03/23/2017] [Indexed: 05/18/2023]
Abstract
Human sleep is highly regulated by temperature. Might climate change-through increases in nighttime heat-disrupt sleep in the future? We conduct the inaugural investigation of the relationship between climatic anomalies, reports of insufficient sleep, and projected climate change. Using data from 765,000 U.S. survey respondents from 2002 to 2011, coupled with nighttime temperature data, we show that increases in nighttime temperatures amplify self-reported nights of insufficient sleep. We observe the largest effects during the summer and among both lower-income and elderly respondents. We combine our historical estimates with climate model projections and detail the potential sleep impacts of future climatic changes. Our study represents the largest ever investigation of the relationship between sleep and ambient temperature and provides the first evidence that climate change may disrupt human sleep.
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Affiliation(s)
- Nick Obradovich
- Belfer Center for Science and International Affairs, Kennedy School of Government, Harvard University, Cambridge, MA 02138, USA
- Media Lab, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Corresponding author. ,
| | - Robyn Migliorini
- Department of Psychiatry, Massachusetts General Hospital, Boston, MA 02114, USA
- Harvard Medical School, Boston, MA 02115, USA
- San Diego State University/University of California San Diego Joint Doctoral Program in Clinical Psychology, San Diego, CA 92182, USA
| | - Sara C. Mednick
- Department of Psychology, University of California, Riverside, Riverside, CA 92521, USA
| | - James H. Fowler
- Departments of Political Science and Medicine, University of California, San Diego, La Jolla, CA 92093, USA
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Kakitsuba N, White MD. Effect of change in ambient temperature on core temperature during the daytime. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2014; 58:901-907. [PMID: 23700199 DOI: 10.1007/s00484-013-0673-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 03/23/2013] [Accepted: 04/20/2013] [Indexed: 06/02/2023]
Abstract
In this study, the hypothesis is tested that continuous increases in ambient temperature (Ta) during daytime would give elevated core and skin temperatures, and consequently better thermal sensation and comfort. Rectal temperature (Tre), skin temperatures and regional dry heat losses at 7 sites were continuously measured for 10 Japanese male subjects in three thermal conditions: cond. 1, stepwise increases in Ta from 26 °C at 9 h00 to 30 °C at 18 h00; cond. 2, steady Ta at 28 °C from 9 h00 to 18 h00 and cond. 3, stepwise decreases in Ta from 30 °C at 9 h00 to 26 °C at 18 h00. Oxygen consumption was measured and thermal sensation and comfort votes were monitored at 15 min intervals. Body weight loss was measured at 1 h intervals. While Tre increased continuously in the morning period in any condition, it increased to a significantly greater (p<0.05) 36.9±0.3 °C at 18 h00 in cond. 1 relative to 36.7±0.28 °C in Cond. 2 and 36.5±0.37 °C in cond. 3. Better thermal comfort was observed in the afternoon and the evening in Cond.1 as compared with the other 2 conditions. Thus, a progressive and appropriate increase in Ta may induce optimal cycle in core temperature during daytime, particularly for a resting person.
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Affiliation(s)
- Naoshi Kakitsuba
- Department of Environment and Technology, School of Science and Technology, Meijo University, 468-8502, Shiogamaguchi 1-501, Tenpaku-ku, Nagoya, Aichi Prefecture, Japan,
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Bonmati-Carrion MA, Middleton B, Revell V, Skene DJ, Rol MA, Madrid JA. Circadian phase assessment by ambulatory monitoring in humans: correlation with dim light melatonin onset. Chronobiol Int 2013; 31:37-51. [PMID: 24164100 DOI: 10.3109/07420528.2013.820740] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The increased prevalence of circadian disruptions due to abnormal coupling between internal and external time makes the detection of circadian phase in humans by ambulatory recordings a compelling need. Here, we propose an accurate practical procedure to estimate circadian phase with the least possible burden for the subject, that is, without the restraints of a constant routine protocol or laboratory techniques such as melatonin quantification, both of which are standard procedures. In this validation study, subjects (N = 13) wore ambulatory monitoring devices, kept daily sleep diaries and went about their daily routine for 10 days. The devices measured skin temperature at wrist level (WT), motor activity and body position on the arm, and light exposure by means of a sensor placed on the chest. Dim light melatonin onset (DLMO) was used to compare and evaluate the accuracy of the ambulatory variables in assessing circadian phase. An evening increase in WT: WTOnset (WTOn) and "WT increase onset" (WTiO) was found to anticipate the evening increase in melatonin, while decreases in motor activity (Activity Offset or AcOff), body position (Position Offset (POff)), integrative TAP (a combination of WT, activity and body position) (TAPOffset or TAPOff) and an increase in declared sleep propensity were phase delayed with respect to DLMO. The phase markers obtained from subjective sleep (R = 0.811), WT (R = 0.756) and the composite variable TAP (R = 0.720) were highly and significantly correlated with DLMO. The findings strongly support a new method to calculate circadian phase based on WT (WTiO) that accurately predicts and shows a temporal association with DLMO. WTiO is especially recommended due to its simplicity and applicability to clinical use under conditions where knowing endogenous circadian phase is important, such as in cancer chronotherapy and light therapy.
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Affiliation(s)
- M A Bonmati-Carrion
- Chronobiology Laboratory, Department of Physiology, University of Murcia , 30100 Espinardo, Murcia , Spain and
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Okamoto-Mizuno K, Mizuno K. Effects of thermal environment on sleep and circadian rhythm. J Physiol Anthropol 2012; 31:14. [PMID: 22738673 PMCID: PMC3427038 DOI: 10.1186/1880-6805-31-14] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Accepted: 05/31/2012] [Indexed: 01/04/2023] Open
Abstract
The thermal environment is one of the most important factors that can affect human sleep. The stereotypical effects of heat or cold exposure are increased wakefulness and decreased rapid eye movement sleep and slow wave sleep. These effects of the thermal environment on sleep stages are strongly linked to thermoregulation, which affects the mechanism regulating sleep. The effects on sleep stages also differ depending on the use of bedding and/or clothing. In semi-nude subjects, sleep stages are more affected by cold exposure than heat exposure. In real-life situations where bedding and clothing are used, heat exposure increases wakefulness and decreases slow wave sleep and rapid eye movement sleep. Humid heat exposure further increases thermal load during sleep and affects sleep stages and thermoregulation. On the other hand, cold exposure does not affect sleep stages, though the use of beddings and clothing during sleep is critical in supporting thermoregulation and sleep in cold exposure. However, cold exposure affects cardiac autonomic response during sleep without affecting sleep stages and subjective sensations. These results indicate that the impact of cold exposure may be greater than that of heat exposure in real-life situations; thus, further studies are warranted that consider the effect of cold exposure on sleep and other physiological parameters.
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Affiliation(s)
- Kazue Okamoto-Mizuno
- Kansei Fukushi Research Center, Tohoku Fukushi University, 1-149-6 Kunimigaoka Aoba Sendai, Miyagi, 981-0935, Japan.
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Egg M, Tischler A, Schwerte T, Sandbichler A, Folterbauer C, Pelster B. Endurance exercise modifies the circadian clock in zebrafish (Danio rerio) temperature independently. Acta Physiol (Oxf) 2012; 205:167-76. [PMID: 22044585 DOI: 10.1111/j.1748-1716.2011.02382.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
AIM Several rodent and human studies revealed that physical exercise acts as a non-photic zeitgeber for the circadian clock. The intrinsic entraining mechanism is still unknown, although it was assumed that the exercise-mediated increase in core temperature could be the underlying zeitgeber. As the homoeostatic control of mammalian core temperature interferes strongly with the investigation of this hypothesis, the present study used the poikilotherm zebrafish to answer this question. METHODS Gene transcription levels of the two circadian core clock genes period1 and clock1 were quantified using real-time qPCR of whole animal zebrafish larvae. RESULTS Long-term endurance exercise of zebrafish larvae aged 9-15 days post-fertilization (dpf) or 21-32 dpf at a constant water temperature of 25 °C caused significantly altered transcription levels of the circadian genes period1 and clock1. Cosinor analysis of diurnal transcription profiles obtained after 3 days of swim training revealed significant differences regarding acrophase, mesor and amplitude of period1, resulting in a phase delay of the gene oscillation. After termination of the exercise bout, at 15 dpf, oscillation amplitudes of both circadian genes were significantly reduced. CONCLUSION The results showed that physical exercise is able to affect the transcription of circadian genes in developing zebrafish larvae. Considering the poikilothermy of zebrafish, an exercise-mediated change in body core temperature could be excluded as the underlying intrinsic zeitgeber. However, the day-active zebrafish arises as a useful model to address the synchronizing effect of exercise on the circadian clock.
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Affiliation(s)
- M Egg
- Institut für Zoologie, Universität Innsbruck, Technikerstr, Austria.
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Olbrich D, Dittmar M. Older poor-sleeping women display a smaller evening increase in melatonin secretion and lower values of melatonin and core body temperature than good sleepers. Chronobiol Int 2012; 28:681-9. [PMID: 21929299 DOI: 10.3109/07420528.2011.599904] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Melatonin concentration and core body temperature (CBT) follow endogenous circadian biological rhythms. In the evening, melatonin level increases and CBT decreases. These changes are involved in the regulation of the sleep-wake cycle. Therefore, the authors hypothesized that age-related changes in these rhythms affect sleep quality in older people. In a cross-sectional study design, 11 older poor-sleeping women (aged 62-72 yrs) and 9 older good-sleeping women (60-82 yrs) were compared with 10 younger good-sleeping women (23-28 yrs). The older groups were matched by age and body mass index. Sleep quality was assessed by the Pittsburgh Sleep Quality Index questionnaire. As an indicator of CBT, oral temperature was measured at 1-h intervals from 17:00 to 24:00 h. At the same time points, saliva samples were collected for determining melatonin levels by enzyme-linked immunosorbent assay (ELISA). The dim light melatonin onset (DLMO), characterizing the onset of melatonin production, was calculated. Evening changes in melatonin and CBT levels were tested by the Friedman test. Group comparisons were performed with independent samples tests. Predictors of sleep-onset latency (SOL) were assessed by regression analysis. Results show that the mean CBT decreased in the evening from 17:00 to 24:00 h in both young women (from 36.57°C to 36.25°C, p < .001) and older women (from 36.58°C to 35.88°C, p < .001), being lowest in the older poor sleepers (p < .05). During the same time period, mean melatonin levels increased in young women (from 16.2 to 54.1 pg/mL, p < .001) and older women (from 10.0 to 23.5 pg/mL, p < .001), being lowest among the older poor sleepers (from 20:00 to 24:00 h, p < .05 vs. young women). Older poor sleepers also showed a smaller increase in melatonin level from 17:00 to 24:00 h than older good sleepers (mean ± SD: 7.0 ± 9.63 pg/mL vs. 15.6 ± 24.1 pg/mL, p = .013). Accordingly, the DLMO occurred at similar times in young (20:10 h) and older (19:57 h) good-sleeping women, but was delayed ∼50 min in older poor-sleeping women (20:47 h). Older poor sleepers showed a shorter phase angle between DLMO and sleep onset, but a longer phase angle between CBT peak and sleep onset than young good sleepers, whereas older good sleepers had intermediate phase angles (insignificant). Regression analysis showed that the DLMO was a significant predictor of SOL in the older women (R(2) = 0.64, p < .001), but not in the younger women. This indicates that melatonin production started later in those older women who needed more time to fall asleep. In conclusion, changes in melatonin level and CBT were intact in older poor sleepers in that evening melatonin increased and CBT decreased. However, poor sleepers showed a weaker evening increase in melatonin level, and their DLMO was delayed compared with good sleepers, suggesting that it is not primarily the absolute level of endogenous melatonin, but rather the timing of the circadian rhythm in evening melatonin secretion that might be related to disturbances in the sleep-wake cycle in older people.
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Affiliation(s)
- Denise Olbrich
- Department of Human Biology, Zoological Institute, Christian-Albrechts-University, Kiel, Germany
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Sleep, vigilance, and thermosensitivity. Pflugers Arch 2011; 463:169-76. [PMID: 22048563 PMCID: PMC3256315 DOI: 10.1007/s00424-011-1042-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 10/09/2011] [Accepted: 10/10/2011] [Indexed: 11/06/2022]
Abstract
The regulation of sleep and wakefulness is well modeled with two underlying processes: a circadian and a homeostatic one. So far, the parameters and mechanisms of additional sleep-permissive and wake-promoting conditions have been largely overlooked. The present overview focuses on one of these conditions: the effect of skin temperature on the onset and maintenance of sleep, and alertness. Skin temperature is quite well suited to provide the brain with information on sleep-permissive and wake-promoting conditions because it changes with most if not all of them. Skin temperature changes with environmental heat and cold, but also with posture, environmental light, danger, nutritional status, pain, and stress. Its effect on the brain may thus moderate the efficacy by which the clock and homeostat manage to initiate or maintain sleep or wakefulness. The review provides a brief overview of the neuroanatomical pathways and physiological mechanisms by which skin temperature can affect the regulation of sleep and vigilance. In addition, current pitfalls and possibilities of practical applications for sleep enhancement are discussed, including the recent finding of impaired thermal comfort perception in insomniacs.
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Romeijn N, Van Someren EJW. Correlated fluctuations of daytime skin temperature and vigilance. J Biol Rhythms 2011; 26:68-77. [PMID: 21252367 DOI: 10.1177/0748730410391894] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Skin temperature shows spontaneous ultradian fluctuations during everyday-life wakefulness. Previous work showed that mild manipulations of skin temperature affect human sleep and vigilance, presumably by influencing neuronal systems involved in both thermal sensing and arousal regulation. We therefore examined whether fluctuations in skin temperature are associated with those in vigilance level under conditions similar to everyday-life situations requiring sustained attention. Eight healthy participants (30.1 ± 8.1 years, M ± SD) participated in a 2-day protocol, during which vigilance and skin temperature were assessed 4 times per day in a silent, dimly lit, temperature-controlled room. Vigilance was assessed by measuring reaction speed and lapses on a novel sustained vigilance task specifically designed to increase lapse rate and range of reaction times. Skin temperature was sampled at 30-second intervals from 3 locations: distal, intermediate, and proximal temperatures were obtained from the middle finger (T(finger) ), the wrist (T(wrist)), and the infraclavicular area (T(chest)), respectively. Furthermore, 3 distal to proximal gradients were calculated. Mixed-effect regression analyses were used to evaluate the association of the fluctuations in temperatures and gradients and those in response speed and lapse probability. Especially the spontaneous fluctuations in proximal temperature were negatively associated with fluctuations in response speed and positively with lapse rate. If individual T(chest) temperature ranges were classified into 10 deciles, they accounted for 23% of the variance in response speed and 11% of the variance in lapse rate. The findings indicate coupling between the spontaneous fluctuations in skin temperature and vigilance during the day and are compatible with the hypothesis of overlap in brain networks involved in the regulation of temperature and vigilance. From an applied point of view, especially proximal skin temperature assessment may be of use in vigilance monitoring.
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Affiliation(s)
- Nico Romeijn
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands.
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Is disturbed intracortical excitability a stable trait of chronic insomnia? A study using transcranial magnetic stimulation before and after multimodal sleep therapy. Biol Psychiatry 2010; 68:950-5. [PMID: 20728874 DOI: 10.1016/j.biopsych.2010.06.028] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2010] [Revised: 06/06/2010] [Accepted: 06/30/2010] [Indexed: 11/21/2022]
Abstract
BACKGROUND Chronic insomnia is a poorly understood disorder. Risk factors for developing chronic insomnia are largely unknown, yet disturbances in brain indexes of arousal seem to accompany the disorder. We here investigate whether insomnia patients and control participants differ with respect to brain responses to direct stimulation, i.e., cortical excitability. Transcranial magnetic stimulation (TMS) offers a method to directly investigate the excitability level of the human cerebral cortex in psychiatric and neurological disease. METHODS We investigated cortical excitability in 16 insomnia patients and 14 carefully matched control participants using absolute and relative amplitudes of motor evoked potentials in response to single- and paired-pulse stimulation using TMS. RESULTS Nonmedicated insomnia patients showed, first, an exaggerated absolute response to both suprathreshold single- and paired-pulse stimulation compared with control participants and second, a reduced relative response to paired-pulse stimulation at long interpulse intervals (i.e., a reduced intracortical facilitation). The abnormal excitability persisted despite sleep therapy that effectively improved sleep quality as well as behavioral and neuroimaging indexes of brain function. CONCLUSIONS The results suggest that a subtly disturbed intracortical excitability characterizes patients with chronic insomnia: a relatively reduced intracortical facilitation in the context of a globally increased absolute excitability. The findings do not resemble TMS findings after sleep deprivation or in sleep apnea and thus seem specific to insomnia. They may offer diagnostic value and implications for assessment of risk to develop this common and disabling disorder.
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ALTENA ELLEMARIJE, VAN DER WERF YSBRANDD, STRIJERS ROBLM, VAN SOMEREN EUSJW. Sleep loss affects vigilance: effects of chronic insomnia and sleep therapy. J Sleep Res 2008; 17:335-43. [DOI: 10.1111/j.1365-2869.2008.00671.x] [Citation(s) in RCA: 166] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Sarabia JA, Rol MA, Mendiola P, Madrid JA. Circadian rhythm of wrist temperature in normal-living subjects A candidate of new index of the circadian system. Physiol Behav 2008; 95:570-80. [PMID: 18761026 DOI: 10.1016/j.physbeh.2008.08.005] [Citation(s) in RCA: 154] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Revised: 08/01/2008] [Accepted: 08/06/2008] [Indexed: 11/19/2022]
Abstract
Most circadian rhythms are under the control of a major pacemaker located in the hypothalamic suprachiasmatic nucleus. Some of these rhythms, called marker rhythms, serve to characterize the timing of the internal temporal order. A marker rhythm, (e.g., one used in chronotherapy) has to be periodic and easy to measure over long periods using non-invasive methods. The most frequent reference variables for human chronotherapy include salivary melatonin or cortisol, urinary 6-sulfatoximelatonin, actimetry and core body temperature (CBT). Recent evidence suggests that sleepiness may be more closely linked to increased peripheral skin temperature than to a core temperature drop, and that distal skin temperature seems to be correlated and phase-advanced with respect to CBT, suggesting that heat loss from the extremities may drive the circadian CBT rhythm. The aim of the present study was to evaluate whether the wrist skin temperature rhythm could be used as a possible index of the human circadian system. To this end, wrist skin temperature (WT1), as determined by a wireless data logger in healthy normal living subjects, was correlated with sleep-wake diaries and oral temperature (OT) recordings. WT and sleep habits were studied in 99 university students. Each subject wore a wireless iButton sensor attached to the inner side of a sport wristband. Our results show that the WT rhythm exhibits an inverse phase relationship with OT, and it is phase-advanced by 60 min with respect to OT. WT started to increase in association to bed time and dropped sharply after awakening. A secondary WT increase, independent of feeding, was observed in the early afternoon. In conclusion, WT wireless recording can be considered a reliable procedure to evaluate circadian rhythmicity, and an index to establish and follow the effects of chronotherapy in normal living subjects.
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Affiliation(s)
- J A Sarabia
- Department of Physiology, Faculty of Biology, University of Murcia, 30100 Espinardo, Murcia, Spain
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Abstract
Circadian rhythms in health and disease have most often been described in terms of their phases and amplitudes, and how these respond to a single exposure to stimuli denoted as zeitgebers. The present paper argues that it is also important to consider the 24-h regularity in the repeated occurrence of the zeitgebers. The effect of the regularity of stimulation by light, melatonin, physical activity, body temperature, corticosteroids and feeding on synchronization within and between the central circadian clock and peripheral oscillators is discussed. In contrast to the phase shifts that can be recorded acutely after a single zeitgeber pulse, the effects of irregularly versus regularly timed zeitgeber can be studied only in long-term protocols and may develop slowly, which is a possible reason why they have received relatively little attention. Several observations indicate a reciprocal relation between the robustness of the endogenous circadian timing system and its dependency on regularly timed zeitgebers. Especially at old age and in disease, proper functioning of the circadian timing system may become more dependent on regularly timed exposure to zeitgeber stimuli. in such conditions, regularly timed exposure to zeitgeber appears to be highly important for health. After a concise introduction on inputs to the central and peripheral oscillators of the circadian timing system, the paper discusses the responses of the circadian timing system and health to (1) a chronic lack of zeitgeber stimuli; (2) fragmented or quasi-ultradian stimuli and (3) repeated phase shifts in stimuli. Subsequently, the specific relevance to aging is discussed, followed by an overview of the effects of experimentally imposed regularly timed stimuli. Finally, a possible mechanism for the gradually evolving effects of repeated regularly timed stimuli on the circadian timing system is proposed.
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Affiliation(s)
- Eus J W Van Someren
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands.
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Kondo M, Tokura H, Wakamura T, Hyun KJ, Tamotsu S, Morita T, Oishi T. Physiological significance of cyclic changes in room temperature around dusk and dawn for circadian rhythms of core and skin temperature, urinary 6-hydroxymelatonin sulfate, and waking sensation just after rising. J Physiol Anthropol 2007; 26:429-36. [PMID: 17704620 DOI: 10.2114/jpa2.26.429] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
The present study investigated whether room temperature (T(a)) cycles around dusk and dawn could influence the circadian rhythm of rectal temperature (T(core)), urinary 6-hydroxymelatonin sulfate during nocturnal sleep, and subjective assessments of sleep in humans. Six female and two male students served as participants. Two different T(a) conditions, cyclic and constant, were established. Two kinds of room temperature were provided to subjects: cyclic T(a) (gradual decrease from 27 degrees C to 24 degrees C between 1800 and 2200 h and gradual increase from 24 degrees C to 27 degrees C between 0300 and 0700 h) and constant T(a) (27 degrees C over 24 h). At cyclic T(a), the circadian nadir of T(core) rhythm was significantly advanced, while T(core) was significantly lower from 2300 to 0200 h and significantly higher from 0600 to 1000 h. The nocturnal concentration of 6-hydroxymelatonin sulfate in the urine during sleep was significantly higher during cyclic T(a). Waking sensation just after rising was significantly better with cyclic T(a). (Skin temperatures in the extremities-T(a)) were significantly higher with cyclic T(a) especially during the evening and night. Our results suggest that gradual change of room temperature in the evening and early morning is important in terms of sleep promotion and fresh awakening. It seems probable that mankind has been evolved to have deeper sleep under the influence of cyclic T(a) around dusk and dawn.
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Affiliation(s)
- Masayuki Kondo
- Heart-ful Living R&DInstitute, Comprehensive Housing R&D Institute, Sekisui House, Ltd, Kyoto 619-0224, Japan.
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Van Someren EJW, Nagtegaal E. Improving melatonin circadian phase estimates. Sleep Med 2007; 8:590-601. [PMID: 17493871 DOI: 10.1016/j.sleep.2007.03.012] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2006] [Revised: 01/18/2007] [Accepted: 03/02/2007] [Indexed: 10/23/2022]
Abstract
The quality and quantity of sleep is to a large extent determined by whether the sleep period is in alignment with the most favorable circadian time window for sleep. Misalignment results in compromised sleep. In order to determine this circadian time window, the 24-h profile of melatonin secretion is generally considered to provide the most optimal estimate. Melatonin secretion occurs only during the night, and several methods to determine its onset and offset markers have been proposed. In spite of the usefulness of determining circadian phase estimates from melatonin, its feasibility is somewhat restricted because the required number of repeated measurements comes at a high cost for compliance and laboratory assays. In addition, the complexity of some of the previously proposed methods to analyze data and obtain phase estimates may require a statistician. We here propose a set of novel functions to better describe the typical melatonin profile, which usually has a rather fixed baseline level during the day, has differences in the steepness of its rising and falling limbs, and may have a nocturnal plateau or even two peaks instead of one during the night. The functions can easily be fitted, even to incomplete or noisy melatonin data, with the most common statistical software packages, and the resulting parameters give direct information on the mentioned characteristics, which provide important additions to complete the usual restricted information on phase and amplitude. We show that the proposed curves fit better than single- to three-harmonic cosine curves to the typical melatonin profiles of both healthy subjects (n=13) and subjects diagnosed with Delayed Sleep Phase Syndrome (DSPS, n=27), Disorders of Initiating and Maintaining Sleep (DIMS, n=9), or sleep complaints not otherwise specified (n=7). Of note, because the functions provide a parsimonious description of the melatonin profile, phase estimates derived from them are more reliable (i.e., robust for noise and data loss). We illustrate that phase estimates deviate on average only by about 10 min in case of the loss of some of the data points and in case of the addition of noise. Finally, we introduce a sparse-sampling schedule tailored to capture the most important aspects of the melatonin curve. It is shown that such schedule - reducing the number of samples by more than 50% - in combination with the proposed functions results in reliable melatonin onset phase estimates, deviating only about 10 min from estimates based on 24 samples. The proposed methods strongly contribute to the feasibility, in terms of both cost and analysis availability, for researchers and clinicians to include the most reliable marker of the circadian timing system in their diagnosis and treatment evaluations.
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Affiliation(s)
- Eus J W Van Someren
- Netherlands Institute for Neuroscience, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands.
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Parker KP, Bailey JL, Rye DB, Bliwise DL, Van Someren EJW. Lowering dialysate temperature improves sleep and alters nocturnal skin temperature in patients on chronic hemodialysis. J Sleep Res 2007; 16:42-50. [PMID: 17309762 DOI: 10.1111/j.1365-2869.2007.00568.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Hemodialysis (HD) induces physiological changes that may affect the ability to dissipate heat and adversely affect sleep. We studied the effects of altering dialysate temperature on polysomnographic measures of nocturnal sleep and the time course of proximal skin temperature. The sample included seven stable HD patients. The three-phase randomized trial was conducted in a research facility. After one acclimatization night, subjects were readmitted in the evening on two additional occasions for 42 h and received HD the next morning in the warm condition (dialysate 37 degrees C) and cool condition (dialysate 35 degrees C) in random order. Continuous proximal skin temperature (axillary, T(ax)) and polysomnographic measures of sleep were recorded the nights before and after HD was administered. Highly significant findings included that the time course of T(ax) was markedly affected by dialysis temperature. There was a greater drop of T(ax) in the early morning following the warm condition than during the baseline nights or in the cool condition. Logistic regression indicated that the odds for the occurrence of sleep and its deeper stages were strongly and positively associated with T(ax). Time of sleep onset was earlier in the cool condition (P = 0.03) with trends toward longer total sleep times (P = 0.09) and shorter rapid-eye-movement latencies (P = 0.09). These observations suggest that the use of cool dialysate during HD may improve nocturnal sleep by decreasing sympathetic activation and sustaining the normally elevated nocturnal skin temperature until later into the morning hours.
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Affiliation(s)
- Kathy P Parker
- Nell Hodgson Woodruff School of Nursing, Emory University, Atlanta, GA 30322-4207, USA.
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Atkinson G, Edwards B, Reilly T, Waterhouse J. Exercise as a synchroniser of human circadian rhythms: an update and discussion of the methodological problems. Eur J Appl Physiol 2006; 99:331-41. [PMID: 17165050 DOI: 10.1007/s00421-006-0361-z] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/13/2006] [Indexed: 11/30/2022]
Abstract
We review the literature on whether exercise is a synchroniser of human circadian rhythms, and highlight the specific methodological problems that are associated with this topic. In applied research, exercise has been investigated as a treatment for jet lag and shift-work problems. In these studies, there have been difficulties in controlling the characteristics of the exercise bout, the athletic status of research participants and exposure to other confounding synchronisers. Therefore, it is unclear at present whether exercise can help mitigate the problems associated with transmeridian travel and shift-work. In laboratory-based experiments, participants have exercised at various times of the day and the change in phase of various circadian rhythms has been measured. Although it is difficult to control for the considerable masking effects of exercise on these estimates of circadian timing, it is clear that nocturnal exercise can induce phase delays in the onset of melatonin. Reports of exercise-induced phase advances of the melatonin rhythm are rarer, as are any phase-shifting effects at all on the body temperature rhythm. In practical terms, the substantial levels of activity needed to obtain phase shifts may not be attainable by the majority of people. In mechanistic terms, the lack of agreement with the phase-shifting effects of bright light suggests that exercise is not exerting its effects via photic entrainment pathways. An alternative explanation may involve exercise-induced hyperthermia. Moreover, it is perplexing why exercise should have a different phase response curve to light, given that humans are diurnally active.
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Affiliation(s)
- Greg Atkinson
- Research Institute for Sport and Exercise Sciences, Henry Cotton Campus, Liverpool John Moores University, Liverpool, UK.
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Maywood ES, O'Neill J, Wong GKY, Reddy AB, Hastings MH. Circadian timing in health and disease. PROGRESS IN BRAIN RESEARCH 2006; 153:253-69. [PMID: 16876580 DOI: 10.1016/s0079-6123(06)53015-8] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Metabolic status varies predictably on a daily and seasonal basis in order to adapt to the cyclical environment. The hypothalamic circadian pacemaker of the suprachiasmatic nuclei (SCN) co-ordinates these metabolic cycles. Circadian timing is based upon a transcriptional/post-translational negative feedback loop involving a series of core clock genes and their products. Local molecular clocks in peripheral tissues are synchronised by a variety of autonomic, paracrine and endocrine cues reflective of SCN time, thereby ensuring internal temporal co-ordination and optimal metabolic function. Disturbances of this co-ordination, as occur in long-term shift work, have a major impact on health.
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Van Someren EJW. Mechanisms and functions of coupling between sleep and temperature rhythms. PROGRESS IN BRAIN RESEARCH 2006; 153:309-24. [PMID: 16876583 DOI: 10.1016/s0079-6123(06)53018-3] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Energy metabolism is strongly linked to the circadian rhythms in sleep and body temperature. Both heat production and heat loss show a circadian modulation. Sleep preferably occurs during the circadian phase of decreased heat production and increased heat loss, the latter due to a profound increase in skin blood flow and, consequently, skin warming. The coupling of these rhythms may differ depending on whether they are assessed in experimental laboratory studies or in habitual sleeping conditions. In habitual sleeping conditions, skin blood flow is for a prolonged time increased to a level hardly ever seen during wakefulness. Possible mechanisms linking the rhythms in sleep and core body and skin temperature are discussed, with a focus on causal effects of changes in core and skin temperature on sleep regulation. It is shown that changes in skin temperature rather than in core temperature causally affect sleep propensity. Contrary to earlier suggestions of a functional role of sleep in heat loss, it is argued that sleep facilitates a condition of increased skin blood flow during a prolonged circadian phase, yet limits heat loss and the risk of hypothermia. Sleep-related behavior including the creation of an isolated microclimate of high temperature by means of warm clothing and bedding in humans and the curling up, huddling and cuddling in animals all help limit heat loss The increase in skin blood flow that characterizes the sleeping period may thus not primarily reflect a thermoregulatory drive. There is indirect support for an alternative role of the prolonged period of increased skin blood flow: it may support maintenance of the skin as a primary barrier in host defense.
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Affiliation(s)
- Eus J W Van Someren
- Netherlands Institute for Neuroscience, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands.
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Gradisar M, Lack L. Relationships between the circadian rhythms of finger temperature, core temperature, sleep latency, and subjective sleepiness. J Biol Rhythms 2004; 19:157-63. [PMID: 15038855 DOI: 10.1177/0748730403261560] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Skin temperature circadian rhythms have been explored relatively recently. It has been suggested that distal and proximal skin temperature changes play a role in the regulation of the core temperature circadian rhythm and sleepiness. The authors investigated the circadian finger and core temperature rhythms in conjunction with the circadian rhythms of subjective and objective sleepiness. Fourteen healthy, young, good sleepers participated in a modified constant-routine procedure in which palmar finger temperature, rectal temperature, subjective sleepiness, and objective sleep latency were measured half-hourly across a 48-h period of enforced wakeful bed rest. Individual curves were adjusted to the group mean temperature minimum time of 0500 h and averaged to create the 4 mean curves. The 5 possible cross-correlation curves between these 4 measures were calculated for half-hourly phase lags from 12 h before to 12 h after the group mean core temperature minimum time. Maximum cross-correlations for each curve suggested that finger temperature preceded core temperature by 3 h (r = -0.22), and subjective sleepiness followed core temperature by 0.5 h (r = -0.33) and objective sleepiness by 2 h (r = 0.29). Although these data are correlational, they are consistent with the notion that finger temperature changes drive core temperature changes, which determine changes of subjective and objective sleepiness.
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Affiliation(s)
- Michael Gradisar
- School of Psychology, Faculty of Social Sciences, Flinders University of South Australia, Bedford Park, South Australia
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Van Someren EJ. Sleep propensity is modulated by circadian and behavior-induced changes in cutaneous temperature. J Therm Biol 2004. [DOI: 10.1016/j.jtherbio.2004.08.003] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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