View clinical trials related to Hypoxia, Altitude.
Filter by:This study analyses the impairment of colour vision during hypobaric hypoxia in volunteers of different groups.
In this study, the investigators will examine the extent to which having suffered coronavirus disease 2019 (COVID19) impacts one's sensibility to hypoxia by means of the 'Richalet test'. The aim of the study is to formulate recommendations for advice in altitude mountain medicine for patients having suffered COVID19. To determine any eventual changes in response to hypoxia, performances by participants having suffered COVID-19 and participants having stayed free of COVID-19 will be both compared intra-individually with previous performances (pre-COVID-19 pandemic) and between both groups of subjects. The investigators hypothesize that patients having suffered COVID19 might perform differently on the cardiopulmonary exercise test compared to before the illness. Based on recent research on COVID19 pathophysiology and -patient follow-up, it might be expected that COVID19 alters the response to hypoxia, thus influencing one's acclimatization capabilities at high altitude, albeit reversibly and/or temporarily. Different alterations of response to hypoxia could be observed. The virus causing COVID19, the "severe acute respiratory syndrome coronavirus 2" (SARS-CoV-2), has the potential to significantly damage the nervous system and to affect cardiorespiratory functions. If SARS-CoV-2 does, similarly to MERS and SARS, induce cardiorespiratory and neurological dysfunction, then COVID19 patients may have impaired hypoxia response after infection and perform worse on the 'Richalet test' in comparison to before the illness. Conversely, reports of high prevalence of dyspnea in patients up to 3 months after SARS-CoV-2 infection, might indicate infection-induced degenerative changes in the carotid bodies, which might lead to sensibilization of the peripheral chemoreceptors to impaired oxygenation. Possibly similar to the impact of aging and smoking on the cardiorespiratory response to hypoxia, this phenomenon of sensibilization could entail an increased hypoxic response in patients having suffered COVID-19. Accordingly, patients might perform better on the 'Richalet test' post-COVID-19 than they did before.
Life expectancy and quality of human life are important indicator of the sustainable development of the society. At the same time, the physical, functional, emotional and psychological components of the of the quality of life evaluation are subjected to be evaluated objectively and corrected using modern medical and socio-psychological methods. According to a fair number of experts, the arsenal of means for functional rehabilitation and health promotion is limited, and its expansion is only possible on the basis of the principles of adaptation medicine and their translation from experimental research into specific preventive and health-promoting technologies. The study is aimed at the development in molecular-endocrine, neuro-visceral and psychophysiological complex mechanisms of human long-term adaptation to systemic modern heating device-based hyperthermia for the development of medical technology focused on optimization in physical functioning, neuro-autonomic regulation, psycho-emotional status and stress- resistance as objective characteristics of humans' quality of life in working age. The novelty of the project is the disclosure of key mechanisms of adaptational direct and cross-effects to the prolonged systemic individually dosed hyperthermia underlying the optimization of stress-resistance, psycho-physiological status and exercise tolerance of practically healthy persons and leading to an increase in the subjectively perceived quality of life. The discovery of the mechanisms of hyperthermically induced neuroplasticity (in terms of the dynamics of oxidative stress, heat shock proteins and the brain derived neurotrophic factor) will also have a scientific significance, which in the long term prospectives may play a role in the development of technics for the prevention and rehabilitation of age-associated neuro-degenerative processes and diseases.
The aim of this study is to compare the psychophysiological effects of terrestrial altitude with a normobaric, hypoxic situation.
Hypoxic Challenge Testing (HCT) is the recommended method for inflight hypoxia risk assessment. Onboard oxygen administration remains controversial. The Federal Aviation Administration approved portable oxygen concentrators (POCs) for onboard oxygen supply but there is lack of evidence about the use, especially in children. The aim of our study is to establish the effectiveness and safety of POCs in infants undergoing HCT.
This study analyses both Protein Expression and emotional alterations during hypobaric hypoxia in volunteers of different groups.
Patients with chronic lung diseases travelling by plane often suffer with symptoms related to lower oxygen levels they are exposed to while flying. Therefore, patients with respiratory conditions are routinely assessed to establish if they need supplemental oxygen in flight. A hypoxic altitude simulation test (HAST) is often part of this assessment and consists in having patients breathe a oxygen/nitrogen blend with a lower oxygen concentration compared to normal room air, simulating in-flight conditions. Oxygen levels are measured before and after the test through a blood sample (from the earlobe or an artery in the wrist) and with a finger probe. In-flight oxygen is required if the oxygen level in the blood is lower than 6.6 kPa. HASTs are time consuming, costly, and require a dedicated hospital appointment. Using historical data, the Investigators developed scores based on capillary blood gas (blood sample from the earlobe), diagnosis and sex to predict the outcome of the HASTs. The Investigators validated the proposed scores in a separate historic cohort of patients and showed it had good concordance with the HASTs results. In this study, the Investigators want to confirm prospectively if the score, based on blood results (venous and/or earlobe), can predict the outcome of the HASTs and therefore reduce the number of tests performed, travel time for patients, and costs for the NHS. All patients, aged 18 or older, who are having a HAST for clinical purposes at the cardio-respiratory lab at Leeds Teaching Hospital NHS Trust will be invited to take part in the study. The Investigators will record diagnosis, results of HAST and previous spirometry from the medical notes, perform a spirometry if not done in the previous 12 months and collect a blood sample (one tube, 4 mls). With these data, the Investigators will calculate the score and assess its agreement with the outcome of the HAST. Each participant's involvement in the study will last for approximately 90-120 minutes, which is the normal duration of a HAST. The Investigators aim to include up to 280 subjects in the study.
Background: Vaso-active polyphenols have been proposed to enhance cognitive performance. Oral administration with the non-flavonoid polyphenol, resveratrol, has been found to modulate cerebral blood flow (CBF); yet, this has not resulted in subsequent predicted benefits to cognitive performance in young, healthy samples. It has been argued that ageing populations who are noted suffer a reduction in CBF and cognition, may possess the subtle deficits to benefit from resveratrol administration. The use of hypoxia has been previously tested by this research group to mimic the decrease in cognitive functioning associated with ageing. Objectives: The current investigation aimed to further assess if a reduced fraction of inspired oxygen (12.7% FiO2) could provide an experimental model of aging in a young, healthy sample. Moreover, the current study also aimed to assess if resveratrol can attenuate the deficits elicited by the reduction in oxygen supply via increased CBF. Design: This repeated measures, double blind, placebo controlled, balanced design assessed the cognitive and CBF effects of resveratrol in hypoxia (equivalent to 4000 m above sea level) and normoxia (sea level). Methods: Twenty-four participants arrived fully fasted (except water) for 12 hours before completing a baseline measure of a cognitive task battery, and taking the treatment for the day (either 500 mg resveratrol or inert placebo). Following a 45 min absorption period, participants completed 3 full repetitions of a cognitive test battery. Changes in cerebral hemodynamics were measured by near-infrared spectroscopy throughout the full testing session.
1) Oxygen Transport in Normobaric versus Hypobaric Hypoxia. 2) The purpose of this study is to examine acute responses in arterial and muscle tissue oxygenation during incremental exercise in normobaric versus hypobaric hypoxia. 3) The participants in this study will consist of 12 recreationally active males and females between the ages of 19 and 45.Recreationally active is defined as participating in moderate to vigorous physical activity for 30 minutes at least 3 days per week.4) Subjects will complete an incremental cycle test to volitional fatigue in three conditions in a randomized counter-balanced order, normobaric normoxia (20.9% O2, 730 mmHg), normobaric hypoxia (14.3% O2, 730 mmHg) and hypobaric hypoxia (20.9% O2, 530mmHg). Two of the three trials will be conducted in an environmental chamber to simulate normobaric normoxia at 350 m (elevation of Omaha, NE) and normobaric hypoxia at 3094 m (elevation of Leadville, CO). The hypobaric hypoxia trial will be conducted in Leadville, Colorado at 3094 m. Trials will be separated by at least two days. Rating of perceived exertion, heart rate, blood oxygenation, respiration rate, muscle tissue oxygenation, and whole body gases will be analyzed during the trials. 5) There is no follow-up as a part of this study.
This study seeks to determine whether a simple, single intervention of Cetirizine / Zyrtec® use can improve exercise performance of active individuals when acutely exposed to altitude. For this project, healthy subjects will perform steady state and progressive work rate exercise, endurance performance time trials, and repeated sprint performance time trials in the laboratory at a simulated altitude of 3000m (9900ft) after dosing with 10 mg of Cetirizine or a placebo in a repeated measures design.