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Zhou X, Wei C, Chen Z, Xia X, Wang L, Li X. Potential mechanisms of ischemic stroke induced by heat exposure. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 952:175815. [PMID: 39197783 DOI: 10.1016/j.scitotenv.2024.175815] [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: 04/08/2024] [Revised: 08/04/2024] [Accepted: 08/24/2024] [Indexed: 09/01/2024]
Abstract
Recent decades of epidemiological and clinical research have suggested that heat exposure could be a potential risk factor for ischemic stroke. Despite climate factors having a minor impact on individuals compared with established risk factors such as smoking, their widespread and persistent effects significantly affect public health. The mechanisms by which heat exposure triggers ischemic stroke are currently unclear. However, several potential mechanisms, such as the impact of temperature variability on stroke risk factors, inflammation, oxidative stress, and coagulation system changes, have been proposed. This article details the potential mechanisms by which heat exposure may induce ischemic stroke, aiming to guide the prevention and treatment of high-risk groups in hot climates and support public health policy development.
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Affiliation(s)
- Xiao Zhou
- Department of Neurology, The Second Hospital of Tianjin Medical University, Tianjin, China
| | - Chanjuan Wei
- Department of Neurology, The Second Hospital of Tianjin Medical University, Tianjin, China
| | - Zhuangzhuang Chen
- Department of Neurology, The Second Hospital of Tianjin Medical University, Tianjin, China
| | - Xiaoshuang Xia
- Department of Neurology, The Second Hospital of Tianjin Medical University, Tianjin, China
| | - Lin Wang
- Department of Geriatrics, The Second Hospital of Tianjin Medical University, Tianjin, China
| | - Xin Li
- Department of Neurology, The Second Hospital of Tianjin Medical University, Tianjin, China; Department of Geriatrics, The Second Hospital of Tianjin Medical University, Tianjin, China.
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James TJ, Corbett J, Cummings M, Allard S, Young JS, Towse J, Carey-Jones K, Eglin C, Hopkins B, Morgan C, Tipton M, Saynor ZL, Shepherd AI. Timing of acute passive heating on glucose tolerance and blood pressure in people with type 2 diabetes: a randomized, balanced crossover, control trial. J Appl Physiol (1985) 2021; 130:1093-1105. [PMID: 33411640 DOI: 10.1152/japplphysiol.00747.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Type 2 diabetes mellitus (T2DM) is characterized by chronic hyperglycemia and progressive insulin resistance, leading to macro and microvascular dysfunction. Passive heating has potential to improve glucose homeostasis and act as an exercise mimetic. We assessed the effect of acute passive heating before or during an oral glucose tolerance test (OGTT) in people with T2DM. Twelve people with T2DM were randomly assigned to the following three conditions: 1) 3-h OGTT (control), 2) 1-h passive heating (40°C water) 30 min before an OGTT (HOT-OGTT), and 3) 1-h passive heating (40°C water) 30 min after commencing an OGTT (OGTT-HOT). Blood glucose concentration, insulin sensitivity, extracellular heat shock protein 70 (eHSP70), total energy expenditure (TEE), heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were recorded. Passive heating did not alter blood glucose concentration [control: 1,677 (386) arbitrary units (AU), HOT-OGTT: 1,797 (340) AU, and OGTT-HOT: 1,662 (364) AU, P = 0.28], insulin sensitivity (P = 0.15), or SBP (P = 0.18) but did increase eHSP70 concentration in both heating conditions [control: 203.48 (110.81) pg·mL-1; HOT-OGTT: 402.47 (79.02) pg·mL-1; and OGTT-HOT: 310.00 (60.53) pg·mL-1, P < 0.001], increased TEE (via fat oxidation) in the OGTT-HOT condition [control: 263 (33) kcal, HOT-OGTT: 278 (40) kcal, and OGTT-HOT: 304 (38) kcal, P = 0.001], increased HR in both heating conditions (P < 0.001), and reduced DBP in the OGTT-HOT condition (P < 0.01). Passive heating in close proximity to a glucose challenge does not alter glucose tolerance but does increase eHSP70 concentration and TEE and reduce blood pressure in people with T2DM.NEW & NOTEWORTHY This is the first study to investigate the timing of acute passive heating on glucose tolerance and extracellular heat shock protein 70 concentration ([eHSP70]) in people with type 2 diabetes. The principal novel findings from this study were that both passive heating conditions: 1) did not reduce the area under the curve or peak blood glucose concentration, 2) elevated heart rate, and 3) increased [eHSP70], which was blunted by glucose ingestion, while passive heating following glucose ingestion, 4) increased total energy expenditure, and 5) reduced diastolic blood pressure.
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Affiliation(s)
- Thomas J James
- School of Sport, Health and Exercise Science, Faculty of Science and Health, University of Portsmouth, United Kingdom.,Diabetes and Endocrinology Department, Portsmouth Hospitals University NHS Trust, Portsmouth, United Kingdom
| | - Jo Corbett
- School of Sport, Health and Exercise Science, Faculty of Science and Health, University of Portsmouth, United Kingdom
| | - Michael Cummings
- Diabetes and Endocrinology Department, Portsmouth Hospitals University NHS Trust, Portsmouth, United Kingdom
| | - Sharon Allard
- Diabetes and Endocrinology Department, Portsmouth Hospitals University NHS Trust, Portsmouth, United Kingdom
| | - John S Young
- School of Pharmacy and Biomedical Sciences, Faculty of Science and Health, University of Portsmouth, United Kingdom
| | - Jonathan Towse
- School of Pharmacy and Biomedical Sciences, Faculty of Science and Health, University of Portsmouth, United Kingdom
| | - Kathryn Carey-Jones
- School of Biological Sciences, Faculty of Science and Health, University of Portsmouth, United Kingdom.,Oaks Healthcare, Cowplain Family Practice, Waterlooville, United Kingdom
| | - Clare Eglin
- School of Sport, Health and Exercise Science, Faculty of Science and Health, University of Portsmouth, United Kingdom
| | - Billy Hopkins
- School of Sport, Health and Exercise Science, Faculty of Science and Health, University of Portsmouth, United Kingdom
| | - Connor Morgan
- School of Sport, Health and Exercise Science, Faculty of Science and Health, University of Portsmouth, United Kingdom
| | - Michael Tipton
- School of Sport, Health and Exercise Science, Faculty of Science and Health, University of Portsmouth, United Kingdom
| | - Zoe L Saynor
- School of Sport, Health and Exercise Science, Faculty of Science and Health, University of Portsmouth, United Kingdom.,Diabetes and Endocrinology Department, Portsmouth Hospitals University NHS Trust, Portsmouth, United Kingdom
| | - Anthony I Shepherd
- School of Sport, Health and Exercise Science, Faculty of Science and Health, University of Portsmouth, United Kingdom.,Diabetes and Endocrinology Department, Portsmouth Hospitals University NHS Trust, Portsmouth, United Kingdom
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Maley MJ, Hunt AP, Stewart IB, Faulkner SH, Minett GM. Passive heating and glycaemic control in non-diabetic and diabetic individuals: A systematic review and meta-analysis. PLoS One 2019; 14:e0214223. [PMID: 30901372 PMCID: PMC6430508 DOI: 10.1371/journal.pone.0214223] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 03/08/2019] [Indexed: 01/22/2023] Open
Abstract
OBJECTIVE Passive heating (PH) has begun to gain research attention as an alternative therapy for cardio-metabolic diseases. Whether PH improves glycaemic control in diabetic and non-diabetic individuals is unknown. This study aims to review and conduct a meta-analysis of published literature relating to PH and glycaemic control. METHODS Electronic data sources, PubMed, Embase and Web of Science from inception to July 2018 were searched for randomised controlled trials (RCT) studying the effect of PH on glycaemic control in diabetic or non-diabetic individuals. To measure the treatment effect, standardised mean differences (SMD) with 95% confidence intervals (CI) were calculated. RESULTS Fourteen articles were included in the meta-analysis. Following a glucose load, glucose concentration was greater during PH in non-diabetic (SMD 0.75, 95% CI 1.02 to 0.48, P < 0.001) and diabetic individuals (SMD 0.27, 95% CI 0.52 to 0.02, P = 0.030). In non-diabetic individuals, glycaemic control did not differ between PH and control only (SMD 0.11, 95% CI 0.44 to -0.22, P > 0.050) and a glucose challenge given within 24 hours post-heating (SMD 0.30, 95% CI 0.62 to -0.02, P > 0.050). CONCLUSION PH preceded by a glucose load results in acute glucose intolerance in non-diabetic and diabetic individuals. However, heating a non-diabetic individual without a glucose load appears not to affect glycaemic control. Likewise, a glucose challenge given within 24 hours of a single-bout of heating does not affect glucose tolerance in non-diabetic individuals. Despite the promise PH may hold, no short-term benefit to glucose tolerance is observed in non-diabetic individuals. More research is needed to elucidate whether this alternative therapy benefits diabetic individuals.
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Affiliation(s)
- Matthew J. Maley
- Institute of Health and Biomedical Innovation, School of Exercise and Nutrition Sciences, Queensland University of Technology, Brisbane, Australia
- Department of Sport and Exercise Science, University of Portsmouth, Portsmouth, United Kingdom
| | - Andrew P. Hunt
- Institute of Health and Biomedical Innovation, School of Exercise and Nutrition Sciences, Queensland University of Technology, Brisbane, Australia
| | - Ian B. Stewart
- Institute of Health and Biomedical Innovation, School of Exercise and Nutrition Sciences, Queensland University of Technology, Brisbane, Australia
| | - Steve H. Faulkner
- Department of Engineering, School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom
| | - Geoffrey M. Minett
- Institute of Health and Biomedical Innovation, School of Exercise and Nutrition Sciences, Queensland University of Technology, Brisbane, Australia
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Jezova D, Radikova Z, Vigas M. Growth hormone response to different consecutive stress stimuli in healthy men: is there any difference? Stress 2007; 10:205-11. [PMID: 17514589 DOI: 10.1080/10253890701292168] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
The contribution of growth hormone (GH), released during acute and repeated stressful situations, to the development of stress-related disorders is often neglected. We have hypothesized that the modulation of the GH response to sequential stress exposure in humans depends mainly on the nature of the stressor. To test this hypothesis, we compared GH responses to different stressful situations, namely aerobic exercise, hypoglycemia and hyperthermia, which were applied in two sequential sessions separated by 80-150 min. In addition, administration of the dopaminergic drug apomorphine was used as a pharmacological stimulus. GH responses to submaximal exercise (bicycle ergometer, increasing work loads of 1.5, 2.0 and 2.5 W/kg, total duration 20 min) and hyperthermia in a sauna (80 degrees C, 30 min) were prevented when preceded by the same stress stimulus. Hypoglycemia induced by insulin (0.1 IU/kg intravenously) resulted in a significant GH response also during the second of the two consecutive insulin tests, though the response was reduced. Administration of apomorphine (0.75 mg subcutaneously) or insulin prevented the increase in GH release in response to a sequential bolus of apomorphine, while hypoglycemia induced a significant elevation in GH levels even if applied after a previous treatment with apomorphine. In conclusion, the feedback inhibition of the GH response to a sequential stress stimulus depends on the stimulus used. Unlike in the case of exercise and hyperthermia, mechanisms involved in the stress response to hypoglycemia appear to overcome the usual feedback mechanisms and to re-induce the GH response when applied after another stimulus.
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Affiliation(s)
- D Jezova
- Institute of Experimental Endocrinology, Slovak Academy of Sciences, Vlarska 3, 83306 Bratislava, Slovakia.
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Wheldon A, Savine RL, Sönksen PH, Holt RIG. Exercising in the cold inhibits growth hormone secretion by reducing the rise in core body temperature. Growth Horm IGF Res 2006; 16:125-131. [PMID: 16644256 DOI: 10.1016/j.ghir.2006.02.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2005] [Revised: 02/28/2006] [Accepted: 02/28/2006] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Ambient temperature alters exercise induced GH secretion. It is unknown whether temperature affects GH secretion at exercise intensities above the anaerobic threshold when other factors may override the relationship seen at lower intensities. DESIGN Cross-over study of ambient temperature on exercise induced GH in swimmers and rowers. SETTING St Thomas Hospital, London. SUBJECTS Ten healthy men (age 21.7+/-0.8 yrs). Five swimmers and five rowers. INTERVENTION Forty-minute exercise test at 105% of anaerobic threshold at room temperature (RT) and at 4 degrees C. MEASUREMENTS Cutaneous and core body temperature. Serum GH concentration. RESULTS Cutaneous body temperature increased during exercise at RT but decreased in the cold. Although core temperature rose in both settings, the rise was greater at RT (p=0.021). GH increased at both temperatures but the onset was delayed by the cold. Peak GH tended to be higher at RT (17.4+/-3.6 microg/L vs. 9.5+/-1.5 microg/L, p=0.07). Total GH secretion was greater at RT (353.3+/-99.1 microg min/L) than 4 degrees C (128.3+/-21.0 microg min/L), p=0.038. Change in core temperature correlated with log peak GH (r=0.66, p=0.039) and log incremental GH (r=0.67, p=0.032) when exercising at 4 degrees C. There was no difference between swimmers and rowers. CONCLUSIONS Exercise at 4 degrees C reduces GH secretion during exercise at intensities above the anaerobic threshold. A change in core body temperature may be one mechanism by which exercise induces GH secretion. The difference in GH between swimmers and rowers during their respective events relates to the conditions under which they compete.
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Affiliation(s)
- Adam Wheldon
- Department of Medicine, Guy's, King's and St Thomas' School of Medicine, King's College London, London SE1 7EH, UK
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Koska J, Rovensky J, Zimanova T, Vigas M. Growth hormone and prolactin responses during partial and whole body warm-water immersions. ACTA PHYSIOLOGICA SCANDINAVICA 2003; 178:19-23. [PMID: 12713511 DOI: 10.1046/j.1365-201x.2003.01116.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIM To elucidate the role of core and skin thermoreceptors in the release of growth hormone (GH) and prolactin (PRL), a sequence of two experiments using whole-body (head-out) and partial (one forearm) hot water immersions was performed. METHODS Experiment 1: Nine healthy men were exposed to head-out and partial water immersions (25 min, 38-39 degrees C). RESULTS Head-out immersion increased the core temperature (38.0 +/- 0.1 vs. 36.7 +/- 0.1 degrees C, P < 0.001) and plasma concentration of the hormones (GH, 16.1 +/- 4.5 vs. 1.2 +/- 0.4 ng mL(-1), P < 0.01; PRL, 9.1 +/- 1.0 vs. 6.4 +/- 0.4 ng mL(-1), P < 0.05). During the partial immersion the core temperature was slightly elevated (36.8 +/- 0.1 vs. 36.6 +/- 0.1, P < 0.001), the concentration of GH increased (4.8 +/- 1.7 vs. 0.6 +/- 0.3, P < 0.05), while plasma PRL decreased (7.6 +/- 0.8, 6.0 +/- 0.6, 5.2 +/- 0.6, P < 0.01). Experiment 2: Seven volunteers immersed one forearm once in 39 degrees C and once in 38 degrees C water. The measurements were performed in 5-min intervals. The GH concentration increased gradually from the beginning of the immersions (min 10; 39 degrees C: 1.9 +/- 1.0 vs. 0.6 +/- 0.3 ng mL(-1), P < 0.01; 38 degrees C: 0.19 +/- 0.03 vs. 0.14 +/- 0.03, P < 0.05) and peaked after their completion (39 degrees C: +10 min, 3.7 +/- 2.0, P < 0.001; 38 degrees C: +15 min, 0.86 +/- 0.61, P < 0.01). The core temperature was unchanged until min 15 of the 39 degrees C bath. Thereafter, it increased about 0.15 degrees C above the baseline (P < 0.01). Immersion in 38 degrees C water did not induce core temperature changes. CONCLUSIONS Peripheral thermoreceptors are involved in GH release when the body is exposed to elevated environmental temperature while a substantial elevation of core temperature is a precondition of PRL release.
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Affiliation(s)
- J Koska
- Institute of experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovakia
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Jezová D, Duncko R. Enhancement of stress-induced pituitary hormone release and cardiovascular activation by antidepressant treatment in healthy men. J Psychopharmacol 2002; 16:235-40. [PMID: 12236631 DOI: 10.1177/026988110201600308] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A randomized, double-blind, placebo-controlled trial was performed to verify the suggestion that (i) in accordance with the results of animal studies, treatment with antidepressants inhibits hormone release in response to stressful stimulation in humans and (ii) drugs with opposing effects on brain serotonine (citalopram and tianeptine) exert similar modulatory effects on neuroendocrine activation during stress. Healthy male volunteers were treated with citalopram (20 mg), tianeptine (37.5 mg) or placebo for 7 days. As a stress stimulus, insulin-induced hypoglycaemia was used. Measurement of hormone concentrations revealed an enhanced release of adrenocorticotropic hormone and growth hormone in response to stress of hypoglycaemia in subjects treated with both antidepressants used. A similar augmentation was observed in systolic blood pressure. Stress-induced prolactin release was potenciated by citalopram only. Plasma renin activity, epinephrine, norepinephrine and cortisol levels failed to be modified by antidepressants. The present study demonstrates that (i) repeated antidepressant treatment in healthy men does not inhibit, but enhances, neuroendocrine activation during stress and (ii) such effects were observed after treatment with antidepressants having opposing actions on brain serotonin, indicating involvement of nonserotoninergic mechanisms.
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Affiliation(s)
- Daniela Jezová
- Laboratory of Pharmacological Neuroendocrinology, Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava.
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