View clinical trials related to Altitude Sickness.
Filter by: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.
The specific aim of this study is to evaluate whether acetazolamide 125mg daily is no worse than acetazolamide 250mg daily in decreasing the incidence of acute mountain sickness (AMS) in travelers to high altitude. The study population is hikers who are ascending at their own rate under their own power in a true hiking environment at the White Mountain Research Station, Owen Valley Lab (OVL) and Bancroft Station (BAR), Bancroft Peak, White Mountain, California
This study analyses both Protein Expression and emotional alterations during hypobaric hypoxia in volunteers of different groups.
The investigators expect to find that different intensity and altitude exposure levels will show what kind of intermittent exposure protocol is more beneficial to athletes and healthy individuals that experience acute exposure to altitude during exercise. This may furthermore be related to acute altitude exposure for recreational exercise use as well.
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 involved human volunteers undertaking a high-altitude expedition. It assessed changes in physiological parameters of relevance to high-altitude cardiopulmonary physiology. Participants included a subgroup of those taking part in an existing adventurous training expedition and were randomised in a 1:1 fashion to receive either intravenous iron or normal saline several weeks prior to departure. During the expedition, participants were investigated by means of transthoracic echocardiography, peripheral oxygen saturation measurement and heart rate monitoring and through the drawing of venous blood samples. Bloods were later analysed for markers of iron status.
Randomized, placebo controlled trial evaluating efficacy of acetazolamide in preventing acute mountain sickness in lowlanders older than 40 years travelling from 760 m to 3'100 m.
Acute mountain sickness (AMS) is one of three syndromes of altitude illness. It is very common when people venture over 2500 meters altitude. This illness is mainly induced by acute exposure to low partial pressure of oxygen at high altitude that will cause a pathological effect on humans. T89 capsule is a modernized industrialized traditional Chinese herbal medicine. It is a botanical drug for oral use. In recent years, several literatures and clinical studies have showed that oral administration of T89 may provide substantial benefits in the prevention or alleviation of symptoms associated with acute mountain sickness (AMS), including nausea, vomiting, headache, dizziness, fatigue, and sleep disturbance. Such effect was also observed in a pilot clinical study recently conducted in Tibet in China. This study is a prospective, double-blind, randomized, placebo-controlled phase 2 clinical trial having three arms including T89 low-dose, T89 high-dose and a placebo controlled group. People will be screened against the inclusion/exclusion criteria after informed consent signed. Eligible subjects will be randomly assigned into one of three arms and instructed to use T89 orally twice daily for 14 days (Days 1-14) before ascending, and 5 days after ascending during the observation period (Days 15-19). The primary efficacy parameter is Lake Louise Scoring System (LLSS) which will be evaluated by subject-self and principal investigator in clinic.
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.
Randomized, placebo controlled trial evaluating the effect of acetazolamide on visuo-motor learning performance in lowlanders older than 40 years travelling from 760 m to 3'100 m.