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Respiratory Care May 2022
Topics: Altitude; Humans; Hypoxia
PubMed: 35473840
DOI: 10.4187/respcare.09897 -
The Clinical Respiratory Journal Mar 2021The aim of this work is to present a review on the impact of genetics and altitude on lung function from classic and recent studies. (Review)
Review
OBJECTIVES
The aim of this work is to present a review on the impact of genetics and altitude on lung function from classic and recent studies.
DATA SOURCE
A systematic search has been carried out in different databases of scientific studies, using keywords related to lung volumes, spirometry, altitude and genetics.
RESULTS
The results of this work have been structured into three parts. First, the relationship between genes and lung function. Next, a review of the genetic predispositions related to respiratory adaptation of people who inhabit high-altitude regions for millennia. Finally, temporary effects and long-term acclimatisation on respiratory physiology at high altitude are presented.
CONCLUSIONS
The works focused on the influence of genetics and altitude on lung function are currently of interest in terms of studying the interactions between genetic, epigenetic and environmental factors in the configuration of the pathophysiological adaptation patterns.
Topics: Acclimatization; Adaptation, Physiological; Altitude; Humans; Lung; Respiratory Physiological Phenomena
PubMed: 33112470
DOI: 10.1111/crj.13300 -
International Journal of Environmental... Sep 2021Many competitive and elite athletes continue to train throughout their pregnancies and many visit or live at altitude. The purpose of this integrative review is to... (Review)
Review
Many competitive and elite athletes continue to train throughout their pregnancies and many visit or live at altitude. The purpose of this integrative review is to synthesize, analyze and critique published studies regarding the safety of serious recreational or elite athletes exercising at altitude while pregnant. Seven databases were searched, and 157 documents were located, which were screened for appropriateness and reduced to seven articles that met the criteria. The studies were analyzed based on maternal and fetal outcomes. Current recommendations for exercising at altitude were based on sedentary individuals who frequently did not have the expected physiological responses based on research on pregnancy and altitude. It is unknown whether competitive and elite athletes would have similar responses to exercise at altitude. More research on exercise at altitude on individuals with a variety of fitness levels is needed.
Topics: Altitude; Athletes; Exercise; Female; Humans; Hypoxia; Pregnancy; Prenatal Care
PubMed: 34501869
DOI: 10.3390/ijerph18179272 -
Journal of Travel Medicine Jun 2023Altitude sojourns increasingly attract individuals of all ages and different health statuses due to the appeal of high-altitude destinations worldwide and easy access to... (Review)
Review
BACKGROUND
Altitude sojourns increasingly attract individuals of all ages and different health statuses due to the appeal of high-altitude destinations worldwide and easy access to air travel. The risk of acute mountain sickness (AMS) when flying to high-altitude destinations remains underemphasized. Thus, this review aims to evaluate the altitude-dependent AMS incidence depending on the mode of ascending, e.g. by air vs terrestrial travel.
METHODS
A literature search was performed to identify the observational studies assessing AMS incidence after acute ascent of primarily healthy adults to real high altitude. In addition, placebo arms of interventional trials evaluating the prophylactic efficacy of various drugs have been separately analysed to confirm or refute the findings from the observational studies. Linear regression analyses were used to evaluate the altitude-dependent AMS incidence.
RESULTS
Findings of 12 observational studies, in which the AMS incidence in 11 021 individuals ascending to 19 different altitudes (2200-4559 m) was evaluated, revealed an impressive 4.5-fold steeper increase in the AMS incidence for air travel as compared with slower ascent modes, i.e. hiking or combined car and/or air travel and hiking. The higher AMS incidence following transportation by flight vs slower means was also confirmed in placebo-treated participants in 10 studies of drug prophylaxis against AMS.
CONCLUSIONS
Due to the short time span in going from low to high altitude, reduced acclimatization likely is the main reason for a higher AMS risk when travelling to high-altitude destinations by flight. To avoid frustrating travel experiences and health risks, appropriate and timely medical advice on how to prepare for air travel to high altitude is of vital importance. Effective preparation options include the use of modern pre-acclimatization strategies and pharmacological prophylaxis by acetazolamide or dexamethasone, or even considering alternate itineraries with more gradual ascent.
Topics: Adult; Humans; Altitude Sickness; Altitude; Acute Disease; Acetazolamide; Air Travel
PubMed: 36694981
DOI: 10.1093/jtm/taad011 -
Journal of Applied Physiology... Oct 2020Residents at high altitude cope with decreasing inspiratory oxygen partial pressure by stimulating erythropoiesis. The increase in hemoglobin levels requires high... (Review)
Review
Residents at high altitude cope with decreasing inspiratory oxygen partial pressure by stimulating erythropoiesis. The increase in hemoglobin levels requires high amounts of additional iron supplied from the diet. Here, we review available data on how iron metabolism adapts when living in a hypoxic environment. Our analysis reveals that long-term adaptation to high altitude enables healthy individuals to maintain their iron stores within the physiological range despite elevated requirements for erythropoiesis. However, in vulnerable populations with increased iron demand (e.g., pregnant women or exercising individuals), iron stores are less likely to be replenished quickly when living at high altitude. Future studies need to address whether different ethnicities have acquired genetic mechanisms to adapt to the elevated iron demand for erythropoiesis at high altitude.
Topics: Acclimatization; Adaptation, Physiological; Altitude; Erythropoiesis; Female; Humans; Hypoxia; Iron; Pregnancy
PubMed: 32853112
DOI: 10.1152/japplphysiol.00019.2020 -
Clinical and Experimental Hypertension... Dec 2023Hypoxia is a physiological state characterized by reduced oxygen levels in organs and tissues. It is a common clinicopathological process and a major cause of health... (Review)
Review
OBJECTIVES
Hypoxia is a physiological state characterized by reduced oxygen levels in organs and tissues. It is a common clinicopathological process and a major cause of health problems in highland areas. Heart rate variability (HRV) is a measure of the balance in autonomic innervation to the heart. It provides valuable information on the regulation of the cardiovascular system by neurohumoral factors, and changes in HRV reflect the complex interactions between multiple systems. In this review, we provide a comprehensive overview of the relationship between high-altitude hypoxia and HRV. We summarize the different mechanisms of diseases caused by hypoxia and explore the changes in HRV across various systems. Additionally, we discuss relevant pharmaceutical interventions. Overall, this review aims to provide research ideas and assistance for in-depth studies on HRV. By understanding the intricate relationship between high-altitude hypoxia and HRV, we can gain insights into the underlying mechanisms and potential therapeutic approaches to mitigate the effects of hypoxia on cardiovascular and other systems.
METHODS
The relevant literature was collected systematically from scientific database, including PubMed, Web of Science, China National Knowledge Infrastructure (CNKI), Baidu Scholar, as well as other literature sources, such as classic books of hypoxia.
RESULTS
There is a close relationship between heart rate variability and high-altitude hypoxia. Heart rate variability is an indicator that evaluates the impact of hypoxia on the cardiovascular system and other related systems. By improving the observation of HRV, we can estimate the progress of cardiovascular diseases and predict the impact on other systems related to cardiovascular health. At the same time, changes in heart rate variability can be used to observe the efficacy of preventive drugs for altitude related diseases.
CONCLUSIONS
HRV can be used to assess autonomic nervous function under various systemic conditions, and can be used to predict and monitor diseases caused by hypoxia at high altitude. Investigating the correlation between high altitude hypoxia and heart rate variability can help make HRV more rapid, accurate, and effective for the diagnosis of plateau-related diseases.
Topics: Humans; Altitude Sickness; Altitude; Heart Rate; Hypoxia; Oxygen
PubMed: 37552638
DOI: 10.1080/10641963.2023.2238923 -
Veterinary Medicine and Science Jul 2022This review covers the challenges of broiler chickens at high altitude, with the focus on growth performance and physiological response. The review also sheds light on... (Review)
Review
This review covers the challenges of broiler chickens at high altitude, with the focus on growth performance and physiological response. The review also sheds light on nutritional and management interventions that help overcome the challenges raised at high altitude. Reduced concentration of atmospheric oxygen is by far the biggest challenge that remarkably affect growth performance and livability of broiler chickens reared in high altitude area. Broiler chickens have endured intensive genetic selection, which potentially predispose them to several metabolic disorders. Hypoxia is an overriding factor that may increase the incidence of metabolic disorders, mainly ascites syndrome at high altitude. Commercial broiler strains cannot fully achieve their genetic potential when raising at highland regions. Careful nutrition and management considerations are required to prevent metabolic disorders when raising broilers at high altitude. In ovo or in-feed nutraceuticals such as l-carnitine and guanidinoacetic acid as well as pharmaceuticals, texture of feed and the use of proper sources and levels of dietary energy and protein are important factors that need to be carefully considered for rearing broiler chickens at high altitude. Management strategies such as lighting programs have been shown to be effective to circumvent ascites prevalence. Special breeding programs may also be considered to develop strains with resistance to ascites.
Topics: Altitude; Animals; Ascites; Chickens; Diet
PubMed: 35290706
DOI: 10.1002/vms3.784 -
Prevalence and risk factors of stroke in high-altitude areas: a systematic review and meta-analysis.BMJ Open Sep 2023The primary objective of this study is to investigate the prevalence and risk factors of stroke in high-altitude areas through a comprehensive systematic review and... (Meta-Analysis)
Meta-Analysis
OBJECTIVE
The primary objective of this study is to investigate the prevalence and risk factors of stroke in high-altitude areas through a comprehensive systematic review and meta-analysis.
DESIGN
This study adopts a systematic review and meta-analysis design.
DATA SOURCES
A thorough search was conducted on databases including PubMed, Web of Science, Embase, Cochrane Library, MEDLINE and SCOPUS, covering the period up to June 2023.
ELIGIBILITY CRITERIA
Studies reporting the prevalence of stroke in high-altitude areas and exploring related risk factors were included, regardless of whether they involved clinical samples or the general population. Studies with incomplete, outdated or duplicate data were excluded.
DATA EXTRACTION AND SYNTHESIS
We performed eligibility screening, data extraction and quality evaluation of the retrieved articles. Meta-analysis was employed to estimate the prevalence and risk factors of stroke in high-altitude areas. The Newcastle-Ottawa Scale was used to assess the risk of bias.
RESULTS
A total of 17 studies encompassing 8 566 042 participants from four continents were included, with altitudes ranging from 1500 m to nearly 5000 m. The pooled prevalence of stroke in high-altitude areas was found to be 0.5% (95% CI 0.3%-7%). Notably, the prevalence was higher in clinical samples (1.2%; 0.4%-2.5%) compared with the general population (0.3%; 95% CI 0.1%-0.6%). When considering geographic regions, the aggregated data indicated that stroke prevalence in the Eurasia plate was 0.3% (0.2%-0.4%), while in the American region, it was 0.8% (0.4%-1.3%). Age (OR, 14.891), gender (OR, 1.289), hypertension (OR, 3.158) and obesity (OR, 1.502) were identified as significant risk factors for stroke in high-altitude areas.
CONCLUSIONS
The findings of this study provide insights into the pooled prevalence of stroke in high-altitude areas, highlighting variations based on geographic regions and sampling type. Moreover, age, gender, hypertension and obesity were found to be associated with the occurrence of stroke.
PROSPERO REGISTRATION NUMBER
CRD42022381541.
Topics: Humans; Altitude; Prevalence; Risk Factors; Obesity; Hypertension; Stroke
PubMed: 37734891
DOI: 10.1136/bmjopen-2022-071433 -
High Altitude Medicine & Biology Sep 2023Li Li, Lin Lin, Bo Wen, Peng-cheng Zhao, Da-sheng Liu, Guo-ming Pang, Zi-rong Wang, Yong Tan, and Cheng Lu. Promising natural medicines for the treatment of... (Review)
Review
Li Li, Lin Lin, Bo Wen, Peng-cheng Zhao, Da-sheng Liu, Guo-ming Pang, Zi-rong Wang, Yong Tan, and Cheng Lu. Promising natural medicines for the treatment of high-altitude illness. . 24:175-185, 2023.-High-altitude illness (HAI) is a dangerous disease characterized by oxidative stress, inflammatory damage and hemodynamic changes in the body that can lead to severe damage to the lungs, heart, and brain. Natural medicines are widely known for their multiple active ingredients and pharmacological effects, which may be important in the treatment of HAI. In this review, we outline the specific types of HAI and the underlying pathological mechanisms and summarize the currently documented natural medicines applied in the treatment of acute mountain sickness and high-altitude cerebral edema, high-altitude pulmonary edema, chronic mountain sickness, and high-altitude pulmonary hypertension. Their sources, types, and medicinal sites are summarized, and their active ingredients, pharmacological effects, related mechanisms, and potential toxicity are discussed. In conclusion, natural medicines, as an acceptable complementary and alternative strategy with fewer side effects and more long-term application, can provide a reference for developing more natural antialtitude sickness medicines in the future and have good application prospects in HAI treatment.
Topics: Humans; Altitude Sickness; Acetazolamide; Altitude; Acute Disease; Brain Edema
PubMed: 37504973
DOI: 10.1089/ham.2022.0139 -
International Journal of Environmental... Mar 2023Nowadays, with the convenience of international traveling and driven by many individuals' fond dreams of challenging high-altitude exercises, high-altitude... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Nowadays, with the convenience of international traveling and driven by many individuals' fond dreams of challenging high-altitude exercises, high-altitude mountaineering is becoming increasingly popular worldwide. Therefore, we performed a meta-analysis to determine the effects of high-altitude mountaineering on cognitive functions in mountaineers before and after climbing.
METHODS
After a thorough electronic literature search and selection, eight studies were included in this meta-analysis, and the conducted test cycles ranged from 8 to 140 days. Eight variables were included in this meta-analysis: the Trail-Making Test (TMB), Digit Span-Forward (DSF), Digit Span-Backward (DSB), Finger Tapping Test-Right (FTR) Finger Tapping Test-Left (FTL), Wechsler Memory Scale Visual (WMSV), the Aphasia Screening Test (Verbal Items) (AST-Ver), and the Aphasia Screening Test (Visual Motor Errors) (AST-Vis). The effect sizes (ES) and forest plots of these eight variables were generated.
RESULTS
Five variables (TMB, ES = 0.39; DSF, ES = 0.57; FTR, ES = 0.50; FTL, ES = 0.16; WMSV, ES = 0.63) out of eight were significantly improved after high-altitude mountaineering, whereas the ES values of DSB, AST-Ver, and AST-Vis did not show significant improvement after climbing.
CONCLUSION
Despite two limitations, namely, methodological issues inherent in the meta-analysis and the inability to explain high heterogeneity between studies, this study is the first meta-analysis that has attempted to specify and compare the cognitive functions of mountaineers before and after high-altitude mountaineering. Furthermore, as a short-term plateau exercise, high-altitude mountaineering has no significant negative impacts on the cognitive functions of climbers. Future research is needed for a long period of high-altitude mountaineering.
Topics: Humans; Mountaineering; Altitude; Altitude Sickness; Cognition; Aphasia
PubMed: 36982007
DOI: 10.3390/ijerph20065101