Active clinical trials for "Altitude Sickness"

This trial is aimed to evaluate the effects of "Wu Zhu Yu Tang" on the prevention of Acute Mountain Sickness(AMS).

The aim of this investigation is to determine the incidence of silent interstitial pulmonary edema by chest ultrasound at moderate altitude (3905m). Secondary endpoints are to detect a suspected association with acute mountain sickness (AMS), co-morbidities and endothelial dysfunction (marker of hypoxia responses, endothelial damage and inflammation).

Recent studies have reported that oxidation of exogenous carbohydrate is reduced under acute hypobaric hypoxic (high altitude; HA) conditions compared to normoxia (sea level; SL) in native lowlanders. However, the mechanisms by which HA suppresses exogenous carbohydrate oxidation are not known. This study will seek to confirm that acute HA exposure decreases exogenous carbohydrate oxidation during steady-state aerobic exercise compared to SL, and explore if the mechanism inhibiting plasma glucose uptake is insulin dependent or independent.

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.

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.

This is a prospective observational study. The purpose is to explore the effect of high altitude hypobaric hypoxia on retinal microcirculation and the change of the thickness of the retina and choroid by optical coherence tomography angiography (OCTA).

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.

This study evaluates the safety and efficacy of the voluntary ventilatory response as prophylaxis for acute mountain sickness, measured by the Lake Louise Self-Report Score, comparing to a group using acetazolamide.

The aim of this study is to compare the psychophysiological effects of terrestrial altitude with a normobaric, hypoxic situation.

Some studies suggest that high-altitude related illnesses - like acute mountain sickness - could be prevented by acclimatisation, reached at low altitude using training in simulated altitude. The purpose of this study is to determine whether training in hypoxia is suitable to prevent acute mountain sickness.