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Journal of the American Geriatrics... Feb 2024
Topics: Humans; Altitude; Geriatrics
PubMed: 38375542
DOI: 10.1111/jgs.18019 -
Scientific Reports Nov 2023Recently, there has been considerable interest in the functions of gut microbiota in broiler chickens in relation to their use as feed additives. However, the...
Recently, there has been considerable interest in the functions of gut microbiota in broiler chickens in relation to their use as feed additives. However, the gut-microbiota of chickens reared at different altitudes are not well documented for their potential role in adapting to prevailing conditions and functional changes. In this context, the present study investigates the functional diversity of gut-microbes in high-altitude (HACh) and low-altitude adapted chickens (LACh), assessing their substrate utilization profile through Biolog Ecoplates technology. This will help in the identification of potential microbes or their synthesized metabolites, which could be beneficial for the host or industrial applications. Results revealed that among the 31 different types of studied substrates, only polymers, carbohydrates, carboxylic acids, and amine-based substrates utilization varied significantly (p < 0.05) among the chickens reared at two different altitudes where gut-microbes of LACh utilized a broad range of substrates than the HACh. Further, diversity indices (Shannon and MacIntosh) analysis in LACh samples showed significant (p < 0.05) higher richness and evenness of microbes as compared to the HACh samples. However, no significant difference was observed in the Simpson diversity index in gut microbes of lowversus high-altitude chickens. In addition, the Principal Component Analysis elucidated variation in substrate preferences of gut-microbes, where 13 and 8 carbon substrates were found to constitute PC1 and PC2, respectively, where γ-aminobutyric acid, D-glucosaminic acid, i-erythritol and tween 40 were the most relevant substrates that had a major effect on PC1, however, alpha-ketobutyric acid and glycyl-L-glutamic acid affected PC2. Hence, this study concludes that the gut-microbes of high and low-altitudes adapted chickens use different carbon substrates so that they could play a vital role in the health and immunity of an animal host based on their geographical location. Consequently, this study substantiates the difference in the substrate utilization and functional diversity of the microbial flora in chickens reared at high and low altitudes due to altitudinal changes.
Topics: Animals; Altitude; Chickens; Glutamic Acid; Gastrointestinal Microbiome; Carbon
PubMed: 38012260
DOI: 10.1038/s41598-023-48147-9 -
American Journal of Biological... Mar 2022Limb length and trunk proportions are determined in a large, taxonomically and environmentally diverse sample of gorillas and related to variation in locomotion,...
OBJECTIVES
Limb length and trunk proportions are determined in a large, taxonomically and environmentally diverse sample of gorillas and related to variation in locomotion, climate, altitude, and diet.
MATERIALS AND METHODS
The sample includes 299 gorilla skeletons, 115 of which are infants and juveniles, distributed between western lowland (G. gorilla gorilla), low and high elevation grauer (G. beringei graueri), and Virunga mountain gorillas (G. b. beringei). Limb bone and vertebral column lengths scaled to body mass are compared between subgroups by age group.
RESULTS
All G. beringei have relatively short 3rd metapodials and manual proximal phalanges compared to G. gorilla, and this difference is apparent in infancy. All G. beringei also have shortened total limb lengths relative to either body mass or vertebral column length, although patterns of variation in individual skeletal elements are more complex, and infants do not display the same patterns as adults. Mountain gorillas have relatively long clavicles, present in infancy, and a relatively long thoracic (but not lumbosacral) vertebral column.
DISCUSSION
A variety of environmental factors likely contributed to observed patterns of morphological variation among extant gorillas. We interpret the short hand and foot bones of all G. beringei as genetic adaptations to greater terrestriality in the last common ancestor of G. beringei; variation in other limb lengths to climatic adaptation, both genetic and developmental; and the larger thorax of G. b. beringei to adaptation to reduced oxygen pressure at high altitudes, again as a product of both genetic differences and environmental influences during development.
Topics: Animals; Humans; Gorilla gorilla; Altitude; Foot Bones
PubMed: 36787793
DOI: 10.1002/ajpa.24443 -
High Altitude Medicine & Biology Jun 2024Ramchandani, Rashi, Ioana Tereza Florica, Zier Zhou, Aziz Alemi, and Adrian Baranchuk. Review of athletic guidelines for high-altitude training and acclimatization.... (Review)
Review
Ramchandani, Rashi, Ioana Tereza Florica, Zier Zhou, Aziz Alemi, and Adrian Baranchuk. Review of athletic guidelines for high-altitude training and acclimatization. 00:000-000, 2024. Exposure to high altitude results in hypobaric hypoxia with physiological acclimatization changes that are thought to influence athletic performance. This review summarizes existing literature regarding implications of high-altitude training and altitude-related guidelines from major governing bodies of sports. A nonsystematic review was performed using PubMed and OVID Medline to identify articles regarding altitude training and guidelines from international governing bodies of various sports. Sports inherently involving training or competing at high altitude were excluded. Important physiological compensatory mechanisms to high-altitude environments include elevations in blood pressure, heart rate, red blood cell mass, tidal volume, and respiratory rate. These responses can have varying effects on athletic performance. Governing sport bodies have limited and differing regulations for training and competition at high altitudes with recommended acclimatization periods ranging from 3 days to 3 weeks. Physiological changes in response to high terrestrial altitude exposure can have substantial impacts on athletic performance. Major sport governing bodies have limited regulations and recommendations regarding altitude training and competition. Existing guidelines are variable and lack substantial evidence to support recommendations. Additional studies are needed to clarify the implications of high-altitude exposure on athletic ability to optimize training and competition.
Topics: Humans; Acclimatization; Altitude; Athletic Performance; Sports; Guidelines as Topic; Hypoxia; Blood Pressure
PubMed: 38207236
DOI: 10.1089/ham.2023.0042 -
High Altitude Medicine & Biology Jun 2022Nicolaou, Laura, Anne Steinberg, Rodrigo M. Carrillo-Larco, Stella Hartinger, Andres G. Lescano, and William Checkley. Living at high altitude and COVID-19 mortality in...
Nicolaou, Laura, Anne Steinberg, Rodrigo M. Carrillo-Larco, Stella Hartinger, Andres G. Lescano, and William Checkley. Living at high altitude and COVID-19 mortality in Peru. . 23:146-158, 2022. Previous studies have reported a lower severity of COVID-19 infections at higher altitudes; however, this association may be confounded by various factors. We examined the association between living at altitude and COVID-19 mortality in Peru adjusting for population density, prevalence of comorbidities, indicators of socioeconomic status, and health care access. Utilizing administrative data across 196 provinces located at varying altitudes (sea level to 4,373 m), we conducted a two-stage analysis of COVID-19 deaths between March 19 and December 31, 2020, Peru's first wave. We first calculated cumulative daily mortality rate for each province and fit lognormal cumulative distribution functions to estimate total mortality rate, and start, peak, and duration of the first wave. We then regressed province-level total mortality rate, start, peak, and duration of the first wave as a function of altitude adjusted for confounders. There were 93,528 recorded deaths from COVID-19 (mean age 66.5 years, 64.5% male) for a cumulative mortality of 272.5 per 100,000 population between March 19 and December 31, 2020. We did not find a consistent monotonic trend between living at higher altitudes and estimated total mortality rate for provinces at 500 - 1,000 m (-12.1 deaths per 100,000 population per 100 m, 95% familywise confidence interval -27.7 to 3.5) or > 1,000 m (-0.3, -2.7 to 2.0). We also did not find consistent monotonic trends for the start, peak, and duration of the first wave beyond the first 500 m. Our findings suggest that living at high altitude may not confer a lower risk of death from COVID-19.
Topics: Aged; Altitude; COVID-19; Female; Humans; Male; Peru; Prevalence
PubMed: 35483043
DOI: 10.1089/ham.2021.0149 -
JMIR MHealth and UHealth Jul 2023Cardiorespiratory fitness plays an important role in coping with hypoxic stress at high altitudes. However, the association of cardiorespiratory fitness with the... (Clinical Trial)
Clinical Trial
BACKGROUND
Cardiorespiratory fitness plays an important role in coping with hypoxic stress at high altitudes. However, the association of cardiorespiratory fitness with the development of acute mountain sickness (AMS) has not yet been evaluated. Wearable technology devices provide a feasible assessment of cardiorespiratory fitness, which is quantifiable as maximum oxygen consumption (VOmax) and may contribute to AMS prediction.
OBJECTIVE
We aimed to determine the validity of VOmax estimated by the smartwatch test (SWT), which can be self-administered, in order to overcome the limitations of clinical VOmax measurements. We also aimed to evaluate the performance of a VOmax-SWT-based model in predicting susceptibility to AMS.
METHODS
Both SWT and cardiopulmonary exercise test (CPET) were performed for VOmax measurements in 46 healthy participants at low altitude (300 m) and in 41 of them at high altitude (3900 m). The characteristics of the red blood cells and hemoglobin levels in all the participants were analyzed by routine blood examination before the exercise tests. The Bland-Altman method was used for bias and precision assessment. Multivariate logistic regression was performed to analyze the correlation between AMS and the candidate variables. A receiver operating characteristic curve was used to evaluate the efficacy of VOmax in predicting AMS.
RESULTS
VOmax decreased after acute high altitude exposure, as measured by CPET (25.20 [SD 6.46] vs 30.17 [SD 5.01] at low altitude; P<.001) and SWT (26.17 [SD 6.71] vs 31.28 [SD 5.17] at low altitude; P<.001). Both at low and high altitudes, VOmax was slightly overestimated by SWT but had considerable accuracy as the mean absolute percentage error (<7%) and mean absolute error (<2 mL·kg·min), with a relatively small bias compared with VOmax-CPET. Twenty of the 46 participants developed AMS at 3900 m, and their VOmax was significantly lower than that of those without AMS (CPET: 27.80 [SD 4.55] vs 32.00 [SD 4.64], respectively; P=.004; SWT: 28.00 [IQR 25.25-32.00] vs 32.00 [IQR 30.00-37.00], respectively; P=.001). VOmax-CPET, VOmax-SWT, and red blood cell distribution width-coefficient of variation (RDW-CV) were found to be independent predictors of AMS. To increase the prediction accuracy, we used combination models. The combination of VOmax-SWT and RDW-CV showed the largest area under the curve for all parameters and models, which increased the area under the curve from 0.785 for VOmax-SWT alone to 0.839.
CONCLUSIONS
Our study demonstrates that the smartwatch device can be a feasible approach for estimating VOmax. In both low and high altitudes, VOmax-SWT showed a systematic bias toward a calibration point, slightly overestimating the proper VOmax when investigated in healthy participants. The SWT-based VOmax at low altitude is an effective indicator of AMS and helps to better identify susceptible individuals following acute high-altitude exposure, particularly by combining the RDW-CV at low altitude.
TRIAL REGISTRATION
Chinese Clinical Trial Registry ChiCTR2200059900; https://www.chictr.org.cn/showproj.html?proj=170253.
Topics: Humans; Acute Disease; Altitude; Altitude Sickness; Exercise Test; Oxygen Consumption
PubMed: 37410528
DOI: 10.2196/43340 -
European Journal of Preventive... Oct 2023Clinical outcome and quality of life of patients with chronic heart failure (HF) have greatly improved over the last two decades. These results and the availability of...
Clinical outcome and quality of life of patients with chronic heart failure (HF) have greatly improved over the last two decades. These results and the availability of modern lifts allow many cardiac patients to spend leisure time at altitude. Heart failure per se does not impede a safe stay at altitude, but exercise at both simulated and real altitudes is associated with a reduction in performance, which is inversely proportional to HF severity. For example, in normal subjects, the reduction in functional capacity is ∼2% every 1000 m altitude increase, whereas it is 4 and 10% in HF patients with normal or slightly diminished exercise capacity and in HF patients with markedly diminished exercise capacity, respectively. Also, the on-field experience with HF patients at altitude confirms safety and shows overall similar data to that reported at simulated altitude. Even 'optimal' HF treatment in patients spending time at altitude or at hypoxic conditions is likely different from optimal treatment at sea level, particularly with regard to the selectivity of β-blockers. Furthermore, high altitude, both simulated and on-field, represents a stimulating model of hypoxia in HF patients and healthy subjects. Our data suggest that spending time at altitude (<3500 m) can be safe even for HF patients, provided that subjects are free from comorbidities that may directly interfere with the adaptation to altitude and are stable. However, HF patients experience a reduction of exercise capacity directly proportional to HF severity and altitude. Finally, HF patients should be tested for functional capacity and must undergo a specific 'hypoxic-tailored treatment' to avoid pharmacological interference with altitude adaptation mechanisms, particularly with regard to the selectivity of β-blockers.
Topics: Humans; Quality of Life; Oxygen Consumption; Hypoxia; Heart Failure; Altitude; Adrenergic beta-Antagonists
PubMed: 37819224
DOI: 10.1093/eurjpc/zwad185 -
Scientific Reports Oct 2022SARS-CoV-2 has spread throughout the world, including areas located at high or very high altitudes. There is a debate about the role of high altitude hypoxia on viral...
SARS-CoV-2 has spread throughout the world, including areas located at high or very high altitudes. There is a debate about the role of high altitude hypoxia on viral transmission, incidence, and COVID-19 related mortality. This is the first comparison of SARS-CoV-2 viral load across elevations ranging from 0 to 4300 m. To describe the SARS-CoV-2 viral load across samples coming from 62 cities located at low, moderate, high, and very high altitudes in Ecuador. An observational analysis of viral loads among nasopharyngeal swap samples coming from a cohort of 4929 patients with a RT-qPCR test positive for SARS-CoV-2. The relationship between high and low altitude only considering our sample of 4929 persons is equal in both cases and not significative (p-value 0.19). In the case of low altitude, adding the sex variable to the analysis, it was possible to find a significative difference between men and women (p-value < 0.05). Considering initially sex and then altitude, it was possible to find a significative difference between high and low altitude for men (p-value 0.05). There is not enough evidence to state that viral load is affected directly by altitude range but adding a new variable as sex in the analysis shows that the presence of new variables influences the relationship of altitude range and viral load. There is no evidence that viral loads (Ct and copies/ml) differ at low or high altitude. Using sex as a co-factor, we found that men have higher viral loads than women at low and moderate altitude locations, while living at high altitude, no differences were found. When Ct values were aggregated by low, moderate, and high viral load, we found no significant differences when sex was excluded from the analysis. We conclude that viral load is not directly affected by altitude, but COVID-19 incidence and mortality are rather affected by socio-demographic and idiosyncratic dynamics.
Topics: Altitude; COVID-19; Female; Humans; Male; Nasopharynx; SARS-CoV-2; Viral Load
PubMed: 36229507
DOI: 10.1038/s41598-022-20516-w -
JAMA Pediatrics Oct 2020Irrespective of their genetic makeup, children living in an ideal home environment that supports healthy growth have similar growth potential. However, whether this...
IMPORTANCE
Irrespective of their genetic makeup, children living in an ideal home environment that supports healthy growth have similar growth potential. However, whether this potential is true for children residing at higher altitudes remains unknown.
OBJECTIVE
To investigate whether altitude is associated with increased risk of linear growth faltering and evaluate the implications associated with the use of the 2006 World Health Organization growth standards, which have not been validated for populations residing 1500 m above sea level.
DESIGN, SETTINGS, AND PARTICIPANTS
Analysis of 133 nationally representative demographic and health cross-sectional surveys administered in 59 low- and middle-income countries using local polynomial and multivariate regression was conducted. A total of 964 299 height records from 96 552 clusters at altitudes ranging from -372 to 5951 m above sea level were included. Demographic and Health Surveys were conducted between 1992 and 2018.
EXPOSURES
Residence at higher altitudes, above and below 1500 m above sea level, and in ideal home environments (eg, access to safe water, sanitation, and health care).
MAIN OUTCOMES AND MEASURES
The primary outcome was child linear growth deficits expressed in length-for-age/height-for-age z scores (HAZ). Associations between altitude and height among all children and those residing in ideal home environments were assessed. Child growth trajectories above and below 1500 m above sea level were compared and the altitude-mediated height deficits were estimated using multivariable linear regression.
RESULTS
In 2010, a total of 842 million people in the global population (approximately 12%) lived 1500 m above sea level or higher, with 67% in Asia and Africa. Eleven percent of the sample was children who resided 1500 m above sea level or higher. These children were born at shorter length and remained on a lower growth trajectory than children residing in areas less than 1500 m above sea level. The negative association between altitude and HAZ was approximately linear through most part of the altitude distribution, indicating no clear threshold for an abrupt decrease in HAZ. A 1000-m above sea level increase in altitude was associated with a 0.163-unit (95% CI, -0.205 to -0.120 units) decrease in HAZ after adjusting for common risk factors using multivariable linear regressions. The HAZ distribution of children residing in ideal home environments was similar to the 2006 World Health Organization HAZ distribution, but only up to 500 m above sea level.
CONCLUSIONS AND RELEVANCE
The findings of this study suggest that residing at a higher altitude may be associated with child growth slowing even for children living in ideal home environments. Interventions addressing altitude-mediated growth restrictions during pregnancy and early childhood should be identified and implemented.
Topics: Altitude; Body Height; Child, Preschool; Cross-Sectional Studies; Ethiopia; Female; Growth Disorders; Humans; Incidence; Infant; Infant, Newborn; Male; Risk Factors; Socioeconomic Factors
PubMed: 32832998
DOI: 10.1001/jamapediatrics.2020.2386 -
Trends in Ecology & Evolution Nov 2021At high elevation or latitude, trees reach low-temperature range limits. In attempting an explanation, the range limits of individual tree species (set by freezing... (Review)
Review
At high elevation or latitude, trees reach low-temperature range limits. In attempting an explanation, the range limits of individual tree species (set by freezing tolerance) and the general limit of the life-form tree (set by thermal growth constraints) need to be distinguished. The general cold edge of the fundamental niche of trees is termed the treeline, by definition, the lower edge of the alpine belt, a most important bioclimatological reference line. Trees can be absent from the treeline due to disturbances or biotic interactions. The actual local edge of tree distribution, the delineation of the realized niche, is driven by stochastic effects. Therefore, treeline theory and hypothesis testing is inevitably tied to the fundamental niche concept.
Topics: Altitude; Trees
PubMed: 34272073
DOI: 10.1016/j.tree.2021.06.011