[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"health-studies-list:{\"conditionNormalized\":\"high-altitude-hypoxia\",\"overallStatus\":[\"RECRUITING\",\"AVAILABLE\",\"NOT_YET_RECRUITING\"],\"orderBy\":\"LastUpdateSubmitDate:desc\",\"size\":25,\"offset\":0}":3,"health-study-condition:high-altitude-hypoxia":29},{"pageToken":4,"total":5,"offset":6,"count":5,"results":7},null,2,0,[8,53],{"id":9,"slug":10,"hasResults":11,"nctId":12,"briefTitle":13,"officialTitle":14,"acronym":4,"eligibilityCriteria":15,"healthyVolunteers":16,"sex":17,"minAge":18,"maxAge":19,"enrollmentInfo":20,"targetDuration":4,"studyType":23,"phases":24,"briefSummary":26,"conditions":27,"keywords":33,"overallStatus":40,"whyStopped":4,"lastUpdateSubmitDate":41,"lastUpdatePostDateStruct":42,"startDateStruct":45,"completionDateStruct":47,"leadSponsor":49,"locationsCount":52},"100602050","phase-4-highcycle-study-acetazolamide-high-altitude-and-plasma-volume-100602050",false,"NCT07118462","HighCycle Study: Acetazolamide, High Altitude and Plasma Volume","HighCycle Study: Effect of Acetazolamide on Plasma Volume During Acute Exposure to High Altitude in Women and Men","Inclusion Criteria:\n\n* Healthy, non-smoking men and women, age 18-44 years, without any disease and need of regular medication (including oral contraceptives).\n* BMI \\>18 kg\u002Fm2 and \\\u003C30 kg\u002Fm2.\n* Born, raised and currently living at altitudes \\\u003C1000 m.\n* Written informed consent.\n* Premenopausal women with an eumenorrheic cycle.\n\nExclusion Criteria:\n\n* Other types of contraceptvies (contraceptives (hormonal intrauterine device, vaginal ring, subcutaneous injections or implants, among others).\n* Pregnancy or nursing\n* Anaemic (haemoglobin concentration \\\u003C10g\u002Fdl).\n* Any altitude trip \\\u003C4 weks before the study.\n* Allergy to acetazolamide and other sulfonamides.",true,"ALL","18 Years","44 Years",{"count":21,"type":22},270,"ESTIMATED","INTERVENTIONAL",[25],"PHASE4","Each year, millions of people living at low altitude (\\\u003C 1,000 m) travel to high altitude (≥ 2,500 m) for work, tourism, or sports activities. These individuals are exposed to hypobaric hypoxia, which can trigger acute mountain sickness (AMS)-the most common form of altitude-related illness. Therefore, understanding the physiological responses to hypoxia that allow acclimatization, as well as the pathophysiology of acute mountain sickness, is of primary importance.\n\nThe hematological response to high-altitude exposure initially includes a reduction in plasma volume (PV), leading to an early increase in hemoglobin concentration within the first 24 hours. In contrast, an increase in hemoglobin mass requires several weeks at high altitude. Recent well-controlled physiological studies conducted in hypobaric chambers have demonstrated that this hypoxia-induced PV contraction results from fluid redistribution from the intravascular to the extravascular compartment, rather than from water loss due to increased diuresis.\n\nProphylaxis of AMS is primarily based on the administration of 250 mg\u002Fday of acetazolamide (ACZ), a carbonic anhydrase inhibitor with a mild diuretic effect. Acetazolamide induces metabolic acidosis, which stimulates ventilation and thereby improves oxygenation. The effect of prophylactic ACZ use during high-altitude exposure on PV in lowlanders remains unknown: it is unclear whether ACZ leads to a greater reduction in PV due to its diuretic effect, or to a smaller hypoxia-induced PV contraction as a result of improved oxygenation induced by increased ventilation.",[28,29,30,31,32],"High Altitude Effects","High Altitude Hypoxia","Acute Mountain Sickness (AMS)","Plasma Volume","Women",[34,35,36,37,38,39],"acetazolamide","plasma volume","acute mountain sickness","high altitude","hypoxia","women","RECRUITING","2025-08-11",{"date":43,"type":44},"2025-08-12","ACTUAL",{"date":46,"type":44},"2024-07-15",{"date":48,"type":22},"2025-12-31",{"name":50,"class":51},"Centre d'Expertise sur l'Altitude EXALT","OTHER",1,{"id":54,"slug":55,"hasResults":11,"nctId":56,"briefTitle":57,"officialTitle":58,"acronym":4,"eligibilityCriteria":59,"healthyVolunteers":16,"sex":17,"minAge":18,"maxAge":60,"enrollmentInfo":61,"targetDuration":4,"studyType":23,"phases":63,"briefSummary":65,"conditions":66,"keywords":4,"overallStatus":40,"whyStopped":4,"lastUpdateSubmitDate":68,"lastUpdatePostDateStruct":69,"startDateStruct":71,"completionDateStruct":73,"leadSponsor":75,"locationsCount":5},"100597841","ketone-monoester-supplements-high-altitude-and-brain-blood-flow-during-exercise-100597841","NCT07063732","Ketone Monoester Supplements, High Altitude, and Brain Blood Flow During Exercise","The Effect of Ketone Monoester Supplementation and High Altitude on Exercising Cerebral Blood Flow","Inclusion Criteria:\n\n\\- Must be a member of the research expedition team travelling to the Barcroft Research Station in White Mountain California\n\nExclusion Criteria:\n\n* BMI \\> 30\n* No prescribed medications (oral contraceptives excluded)\n* History of smoking\n* Currently following a ketogenic diet or consuming exogenous ketogenic supplements\n* History of heart, lung, blood vessel, or kidney disease\n* Currently pregnant","35 Years",{"count":62,"type":22},14,[64],"NA","The purpose of this trial is to investigate the effect of acute ketone monoester ingestion (0.6 g KME\u002Fkg body weight) on the occurrence of the ventilatory threshold and the subsequent response of blood velocity in cerebral arteries during a maximal exercise test at low altitude and high altitude.",[29,67],"Exercise","2025-07-02",{"date":70,"type":44},"2025-07-14",{"date":72,"type":44},"2025-05-28",{"date":74,"type":22},"2025-08-31",{"name":76,"class":51},"McMaster University"]