1,721,013 research outputs found
Case studies in physiology: Nocturnal cardiorespiratory adaptive differences between an Italian trekker and a Nepali guide
Full text linkThe cardiopulmonary system is a physiological cornerstone in the adaptive response to hypobaric hypoxia. Portable devices make it feasible nowadays to precisely assess the response to high altitude (HA) expeditions. In this study, we investigated breathing and arterial blood pressure responses during a Himalayan trek from 665 m to 4,780 m altitude in a white European (Italian) sojourner and a native Nepali (Tamang) guide, both healthy males. Resting diurnal and nocturnal data were acquired by means of ambulatory blood pressure monitoring (ABPM) and sleep apnea monitoring. We found an increase in the mean diurnal arterial blood pressure. Nocturnal blood pressure dipping was confirmed at all altitudes. Oxygen saturation decreased at altitude, with its additional nocturnal fall. Sleep apneic episodes, present in the Italian only, increased with altitude. We conclude that the nocturnal, more than diurnal, cardiorespiratory function is affected by HA hypoxia. Further studies should address the role of ethnicity, medications, and sociodemographic factors in the cardiorespiratory responses to hypobaric hypoxia
Psychophysiological factors in prolonged scuba-diving: a longitudinal case study of an elite diver
No full textBACKGROUND: The issue of prolonged diving has grown in importance, in light of the significant number of divers being lost at sea and exposed to prolonged immersion. Therefore, the aim of this longitudinal case study was to investigate the psychological and pathophysiological responses of an elite diver exposed to prolonged scuba dive.METHODS: The project assessed adaptive responses to increasingly longer dives of an expert male diver through ten years (2004/2014): Pisa (24 hours, swimming pool: vitals and psychometric evaluation), Tremiti Islands (29 hours, open seawater: vitals, and feasibility at sea), Siracusa (32 hours, open seawater: vitals, platelet aggregation, postural balance, psychometric evaluation) and Maratea (36 hours, open seawater: vitals, muscle biopsy: intracellular calcium concentration, superoxide anion production).RESULT S: Weight showed a constant reduction after each attempt. Psychometric tests detected a reduction in mood and cognitive domain. After the 32 hours-long attempt at sea, the subject's postural stability showed to be impaired while an increased platelet activation was detected. Finally, in the 36 hours-long attempt, significantly increased levels of superoxide anion and intracellular calcium were detected on muscle biopsy after the dive, thus suggesting that the athlete was subjected to high oxidative stress level throughout the longer attempt.CONCLUSIONS: Postural balance reduction, the muscular tissue oxidation increase and psychologic adaptation detected with this longitudinal study should be thoroughly assessed in the future in a larger sample because of the important implications on scuba-diving and search and rescue activities
Spatial Abilities at High Altitude Exploring the Role of Cultural Strategies and Hypoxia
No full textBondi, Danilo, Vittore Verratti, Raffaella Nori, Laura Piccardi, Giulia Prete, Tiziana Pietrangelo, and Luca Tommasi. Spatial abilities at high altitude Exploring the role of cultural strategies and hypoxia. High Alt Med Biol. 22 157-165, 2021. Background Over the past couple of decades, the number of people of different cultures traveling to places of high altitude (HA) increased. At HA, a decline in cognitive abilities has been described, including spatial skills. However, it is still unknown whether people accustomed to hypobaric hypoxia are less susceptible to cognitive decline. Method We aimed to determine if three ethnic groups would show any difference in the performance of spatial abilities. Italian trekkers (46.20 ± 15.83 years), Nepalese porters (30.33 ± 8.55 years), and lowlander and highlander Sherpas (30.33 ± 8.55 and 37.00 ± 16.51 years) were tested with a building photograph recognition, a map orienting, and a mental rotation task during a Himalayan expedition. Accuracy and response times were collected at low altitude (LA) and HA. Results Nepalese performed the worst (photograph task p = 0.015, η2p = 0.36; map task p = 0.016, η2p = 0.36), but the difference was mitigated after correcting for length of schooling. Participants took more time to respond at LA than in HA condition (photograph task 24.0 ± 15.3 seconds vs. 12.7 ± 6.3 seconds, p = 0.008, η2p = 0.57; map task 12.5 ± 1.8 seconds vs. 7.8 ± 0.6 seconds, p = 0.038, η2p = 0.40). In the map task, participants performed with greater accuracy at LA (5.1 ± 0.4 vs. 4.4 ± 0.4 number of correct responses, p = 0.006, η2p = 0.59). Conclusions Altitude hypoxia elicited impairments in cognitive spatial tasks. This may be due to the inability to acquire new unfamiliar patterns, and to the difficulty in managing a high cognitive workload. The ethnic differences were ascribed to schooling, even we consider the different system of reference usually exploited in each culture (egocentric dependent, or allocentric independent from the personal viewpoint), and that Westerners are more likely to focus on specific details of the scene. Further studies should investigate the diverse strategies to complete spatial tasks
Human development and reproduction in space-a European perspective.
No full textThis review summarises key aspects of the first reproductive and developmental systems Science Community White Paper, supported by the European Space Agency (ESA). Current knowledge regarding human development and reproduction in space is mapped to the roadmap. It acknowledges that sex and gender have implications on all physiological systems, however, gender identity falls outside the scope of the document included in the white paper collection supported by ESA. The ESA SciSpacE white papers on human developmental and reproductive functions in space aim to reflect on the implications of space travel on the male and female reproductive systems, including the hypothalamic-pituitary-gonadal (HPG) reproductive hormone axis, and considerations for conception, gestation and birth. Finally, parallels are drawn as to how this may impact society as a whole on Earth
Sperm forward motility is negatively affected by short-term exposure to altitude hypoxia
No full textHuman exposure to altitude is a model to study the role of oxygen in different areas of physiology and pathophysiology. The aim of this study was to evaluate whether a short exposure to hypoxia (5 days) combined with exercise, at altitude ranging from 900 m above sea level to 5895 m above sea level (Kilimanjaro Expedition) can modify seminal and reproductive hormonal parameter levels in human beings. During the ascent, blood oxygen saturation at 3.848 m above sea level was found to be decreased when compared to sea level (P < 0.02). The sperm forward motility at sea level after the expedition showed a significant reduction (P < 0.02). There were no changes in other seminal parameters among those compared. Determination of the hormonal plasma concentrations showed that baseline values of follicle-stimulating hormone, total testosterone, prolactin and oestradiol were unchanged at sea level after the hypoxic experience, with respect to baseline values at sea level. On the other hand, luteinising hormone levels after altitudes trekking significantly increased compared to levels before the expedition (P < 0.05). Because of the short-term exposure, we can assume that the reduced forward motility described here may result from the effects of the acute altitude hypoxia on spermatozoa during the epididymal transit where they mature acquiring their motility
Effects Of Hypoxia On Nocturnal Erection Quality: A Case Study From The Manaslu Expedition
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Segmented-Beat Modulation Method-Based Procedure for Extraction of Electrocardiogram-Derived Respiration from Data Acquired by Wearable Sensors During High-Altitude Activity
No full textHigh-altitude sports are affected by hypoxic stress-related alterations and, consequently, may trigger severe events such as sport-related sudden death; thus, into-the-jield monitoring of respiration is essential. A Segmented-Beat Modulation Method (SBMM)-based procedure was previously proposed to extract electrocardiogram (ECG)- derived respiration (EDR). The aim of this study is to validate SBMM-based procedure for EDR extraction in data acquired by wearable sensors during high-altitude physical activities. Respiration signal (RES) and ECG were recorded using BioHarness 3.0 by Zephyr from 3 expeditioners, while performing a trek up to 4, 556m of altitude. EDR it was extracted from ECG by SBMM-based procedure. RES and EDR were segmented into 60-second windows and characterized in terms of breathing rate (BRRES and BREDR, respectively). BRRES and BREDR were compared by absolute difference (|δ|), concordance correlation coefficient (CCC) and linear regression analysis. Results confirmed EDR goodness, proved by low values of |δ| (2[1;4]cpm), satisfactory CCC(0.62; P-value < 0.05) and good fit of regression line (BRRES=0.91· BREDR+4.47cpm). In conclusion, SBMM-based procedure is a good method to extract EDR from data acquired by wearable sensors during high-altitude physical activities
Effect of high-altitude trekking on blood pressure and on asymmetric dimethylarginine and isoprostane production: Results from a Mount Ararat expedition
No full textThe study aimed at exploring the mechanisms behind blood pressure and heart rate changes upon acute altitude exposure utilizing urinary excretion of biochemical factors involved in cardiovascular regulation. The study was conducted on 12 lowlander native male mountain climbers, living at sea level, exposed to altitudes ranging from 1800 to 5147 m above sea level over 4 days, during their ascent to Mount Ararat (Turkey). Blood pressure (measured by oscillometric method), heart rate, and blood oxygen saturation (SpO2) were recorded at rest (on awakening before food intake), in hypoxic conditions at 4200 m and at sea level before and after the altitude expedition. In the same study conditions (ie before-during-after the expedition), first-voided urinary samples were collected and assayed for 8-iso-prostaglandin F2α (8-iso-PGF2α) and asymmetric dimethylarginine (ADMA) determination. Heart rate, and systolic and diastolic blood pressures were higher (P <.05) at high altitude than at the sea level. Furthermore, both urinary 8-iso-PGF2α and ADMA were significantly elevated (P <.01) at high altitude and returned to normal levels soon after returning to sea level. A 4-day exposure to high-altitude hypoxia induced a temporary increase in blood pressure and heart rate, confirming previous findings. Blood pressure increase at high altitude was associated with significantly enhanced production of biochemical mediators such as 8-iso-PGF2α, catecholamines, and ADMA, although we could not demonstrate a direct link between these parallel significant changes probably due to the forcefully limited sample size of our study, carried out in challenging environmental conditions at very high altitude
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