{"id":1109,"date":"2026-04-17T14:48:22","date_gmt":"2026-04-17T14:48:22","guid":{"rendered":"https:\/\/medycyna-gorska.pl\/?p=1109"},"modified":"2026-04-17T17:07:12","modified_gmt":"2026-04-17T17:07:12","slug":"altitude-sickness-complete-guide","status":"publish","type":"post","link":"https:\/\/medycyna-gorska.pl\/en\/altitude-sickness-complete-guide\/","title":{"rendered":"Altitude Sickness \u2014 Complete Medical Guide"},"content":{"rendered":"\n<p><strong>Altitude sickness<\/strong> is the most common medical condition affecting travelers at high elevations. In its mild form it is self-limiting and resolves after a day of rest, but if neglected it can progress within hours to <strong>high-altitude cerebral edema (HACE)<\/strong> or <strong>high-altitude pulmonary edema (HAPE)<\/strong> \u2014 life-threatening emergencies that require immediate evacuation. This complete guide explains everything you need before an expedition: how to recognize early symptoms, when to take acetazolamide, how acclimatization works, and what to do when a companion starts behaving strangely.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><picture><source type=\"image\/webp\" srcset=\"https:\/\/medycyna-gorska.pl\/wp-content\/uploads\/2022\/07\/IMG_20220413_124142.webp\"><img decoding=\"async\" src=\"https:\/\/medycyna-gorska.pl\/wp-content\/uploads\/2022\/07\/IMG_20220413_124142.jpg\" alt=\"Khumbu valley near Everest Base Camp (5364 m)\" class=\"wp-image-800\"\/><\/picture><figcaption class=\"wp-element-caption\">Khumbu valley \u2014 a region where first AMS symptoms appear in roughly half of trekkers above 4000 m.<\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Altitude sickness in a nutshell<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>AMS (Acute Mountain Sickness)<\/strong> \u2014 mild form. Headache, nausea, fatigue. Affects 25\u201350% of travelers above 3500 m.<\/li>\n<li><strong>HACE<\/strong> \u2014 cerebral edema. Near 100% mortality untreated. Key symptom: <strong>ataxia<\/strong> (loss of balance).<\/li>\n<li><strong>HAPE<\/strong> \u2014 pulmonary edema. <strong>Dyspnea at rest<\/strong> = alarm. More common than HACE.<\/li>\n<li><strong>300\u2013500 m rule<\/strong>: above 3000 m do not raise sleeping altitude faster than 300\u2013500 m\/day.<\/li>\n<li><strong>SpO\u2082 70%<\/strong> at 5000 m in a person who feels well is <em>normal<\/em> \u2014 treat the patient, not the number.<\/li>\n<li><strong>The only effective treatment for severe forms<\/strong> \u2014 immediate descent plus oxygen.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">What is altitude sickness?<\/h2>\n\n\n\n<p>The umbrella term &#8220;altitude sickness&#8221; covers three distinct entities sharing one cause \u2014 <strong>hypoxia<\/strong> caused by reduced atmospheric pressure at altitude:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>AMS (Acute Mountain Sickness)<\/strong> \u2014 the mild form. Headache plus at least one of: nausea, fatigue, dizziness. Reversible.<\/li>\n<li><strong>HACE (High-Altitude Cerebral Edema)<\/strong> \u2014 life-threatening. Without treatment, death within hours.<\/li>\n<li><strong>HAPE (High-Altitude Pulmonary Edema)<\/strong> \u2014 also life-threatening. More common than HACE and often appears without preceding AMS.<\/li>\n<\/ul>\n\n\n\n<p>AMS, HACE and HAPE are not always consecutive &#8220;stages&#8221; of the same disease. HAPE can strike someone without prior AMS symptoms \u2014 especially after rapid ascent or in individuals with genetic predisposition. In expedition practice HAPE is seen roughly three times more often than HACE.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Pathophysiology \u2014 why we feel bad at altitude<\/h2>\n\n\n\n<p>Counterintuitively, on the summit of Mount Everest the <strong>percentage of oxygen in air remains identical<\/strong> to sea level \u2014 around 21%. What changes is <strong>atmospheric pressure<\/strong>. At 5364 m (Everest Base Camp) it is about 540 hPa \u2014 half the sea-level value. Oxygen molecules are more dispersed and fewer reach the alveoli with each breath.<\/p>\n\n\n\n<p>The body responds with compensatory changes: respiratory rate rises, cardiac output increases, kidneys excrete bicarbonate, and bone marrow produces more red cells. When these mechanisms cannot keep up \u2014 hypoxic tissue damage appears, capillary leakage in lungs (HAPE) or brain (HACE), and classic AMS symptoms. Worth knowing: <strong>if Mount Everest were located in Alaska, climbing it without supplemental oxygen would be physiologically impossible<\/strong> \u2014 because of even lower atmospheric pressure far from the equator.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">At what altitude does altitude sickness start?<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>1500\u20132500 m<\/strong> \u2014 in especially susceptible people (after illness, dehydrated) headaches and fatigue possible.<\/li>\n<li><strong>2500\u20133500 m<\/strong> \u2014 first AMS symptoms in approximately 20% of travelers, especially after rapid car or cable-car ascent.<\/li>\n<li><strong>3500\u20135000 m<\/strong> \u2014 AMS affects 25\u201350% of population; first HAPE and HACE cases.<\/li>\n<li><strong>5000\u20136000 m<\/strong> \u2014 threshold of severe symptoms. Clinical observation during expedition medical care in the Everest region: first serious problems between 4000 and 5000 m, but the real line above which it is hard to find anyone symptom-free is around 5000 m.<\/li>\n<li><strong>Above 6000 m<\/strong> \u2014 deterioration processes begin to outweigh regeneration. Extended stays become exhausting.<\/li>\n<li><strong>Above 8000 m (&#8220;death zone&#8221;)<\/strong> \u2014 acclimatization is impossible. Every minute without oxygen brings the body closer to death.<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image size-large\"><picture><source type=\"image\/webp\" srcset=\"https:\/\/medycyna-gorska.pl\/wp-content\/uploads\/2023\/08\/IMG_20220421_103008.webp\"><img decoding=\"async\" src=\"https:\/\/medycyna-gorska.pl\/wp-content\/uploads\/2023\/08\/IMG_20220421_103008.jpg\" alt=\"Everest Base Camp 5364 m \u2014 where most trekkers develop at least some AMS symptoms\" class=\"wp-image-773\"\/><\/picture><figcaption class=\"wp-element-caption\">Everest Base Camp at 5364 m \u2014 the real threshold above which it is difficult to find anyone without any altitude-related symptoms.<\/figcaption><\/figure>\n\n\n\n<p>Risk factors: previous AMS\/HAPE\/HACE episode, rapid ascent (less than 300 m\/day above 3000 m), dehydration, respiratory infection, alcohol consumption, certain medications (e.g. strong sedatives).<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">AMS symptoms and Lake Louise Score<\/h2>\n\n\n\n<p>The main and earliest AMS symptom is <strong>headache<\/strong> \u2014 it may affect up to 70% of trekkers above 3500 m. Other classic symptoms:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Loss of appetite, nausea, vomiting<\/li>\n<li>Fatigue and weakness out of proportion to effort<\/li>\n<li>Dizziness<\/li>\n<li>Sleep disturbances (insomnia, Cheyne-Stokes breathing)<\/li>\n<\/ul>\n\n\n\n<p>The <strong>Lake Louise Score<\/strong> \u2014 a standardized tool developed by mountain medicine physicians \u2014 is used to grade severity. Each of four symptoms scores 0\u20133 and the sum falls into one of three brackets:<\/p>\n\n\n\n<figure class=\"wp-block-table is-style-stripes\"><table><thead><tr><th>Symptom<\/th><th>Severity<\/th><th>Points<\/th><\/tr><\/thead><tbody><tr><td><strong>Headache<\/strong><\/td><td>none \/ mild \/ moderate \/ disabling<\/td><td>0 \/ 1 \/ 2 \/ 3<\/td><\/tr><tr><td><strong>GI symptoms<\/strong><\/td><td>none \/ poor appetite \/ moderate nausea \/ severe vomiting<\/td><td>0 \/ 1 \/ 2 \/ 3<\/td><\/tr><tr><td><strong>Fatigue\/weakness<\/strong><\/td><td>none \/ mild \/ moderate \/ disabling<\/td><td>0 \/ 1 \/ 2 \/ 3<\/td><\/tr><tr><td><strong>Dizziness<\/strong><\/td><td>none \/ mild \/ moderate \/ disabling<\/td><td>0 \/ 1 \/ 2 \/ 3<\/td><\/tr><\/tbody><\/table><figcaption class=\"wp-element-caption\">Lake Louise Score \u2014 AMS severity assessment<\/figcaption><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">3\u20135 points: mild AMS<\/h3>\n\n\n\n<p>Rest, hydration (2\u20134 L\/day with electrolytes), analgesics (500\u20131000 mg paracetamol every 6 h, 200\u2013400 mg ibuprofen, 500\u20131000 mg metamizole). <strong>Do not ascend<\/strong> until symptoms resolve. Most cases resolve within 24\u201348 h at the same altitude.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">6\u20139 points: moderate AMS<\/h3>\n\n\n\n<p>The person may stay at current altitude but absolutely must not ascend. Management as for mild AMS + consider <strong>acetazolamide 125\u2013250 mg twice daily<\/strong>. If symptoms do not resolve within 24 h or SpO\u2082 drops significantly \u2014 descend 500\u20131000 m.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">10\u201312 points: severe AMS<\/h3>\n\n\n\n<p>Condition immediately preceding or already life-threatening. HACE or HAPE can develop any moment. <strong>Give acetazolamide 250 mg twice daily<\/strong> and initiate evacuation: 500\u20131000 m descent on foot (stabilizing position, with escort) or by helicopter, depending on patient condition and terrain.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">High-altitude cerebral edema (HACE)<\/h2>\n\n\n\n<p>HACE is brain tissue swelling caused by hypoxia and capillary leakage. Tissue compressed by the skull causes neurological disturbances \u2014 balance centers rupture first (located in the posterior cranial fossa, particularly susceptible to pressure).<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Key HACE symptoms<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Ataxia<\/strong> (loss of balance) \u2014 patient cannot walk a straight line, cannot stand stable with eyes closed<\/li>\n<li><strong>Agitation or confusion<\/strong> \u2014 slurred speech, illogical responses<\/li>\n<li>Severe headache unresponsive to painkillers<\/li>\n<li>SpO\u2082 often &lt;50% \u2014 critically low<\/li>\n<li>Vomiting, sometimes papilledema<\/li>\n<\/ul>\n\n\n\n<p>A characteristic case from expedition practice: a participant reports weakness and diarrhea in the evening; the team assumes food poisoning. During the night he collapses in the lodge corridor \u2014 slurred speech, agitation, unable to stand. SpO\u2082 50%. Diagnosis: HACE. Management: oxygen + dexamethasone + helicopter evacuation at dawn. The patient survives because action was taken within hours, not days.<\/p>\n\n\n\n<p>More on diagnosis and treatment in a dedicated article \u2014 <a href=\"\/en\/hace-how-to-recognize-most-dangerous-form-of-altitude-sickness\/\">HACE \u2014 recognition and treatment<\/a>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">High-altitude pulmonary edema (HAPE)<\/h2>\n\n\n\n<p>HAPE is fluid leakage from pulmonary capillaries into alveoli. Mechanism: hypoxia causes pulmonary vasoconstriction \u2192 pressure rises \u2192 microvascular damage \u2192 fluid in alveolar space \u2192 impaired gas exchange. The patient literally &#8220;drowns in their own fluids&#8221;.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Key HAPE symptoms<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Dyspnea at rest<\/strong> \u2014 this is the alarm signal. Exertional breathlessness at altitude is normal; dyspnea while sitting or standing = HAPE until proven otherwise.<\/li>\n<li>Persistent cough, often with <strong>pink or bloody sputum<\/strong> (foamy exudate)<\/li>\n<li>Chest tightness, feeling of &#8220;lung congestion&#8221;<\/li>\n<li>Rapid breathing and elevated heart rate<\/li>\n<li>Audible crackles on auscultation, sometimes even without stethoscope<\/li>\n<\/ul>\n\n\n\n<p>More on diagnosis and treatment \u2014 <a href=\"\/en\/hape-recognition-and-treatment-of-high-altitude-pulmonary-edema-during-high-altitude-expeditions\/\">HAPE \u2014 recognition and treatment<\/a>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Differential diagnosis \u2014 is it really AMS?<\/h2>\n\n\n\n<p>Not every headache at altitude is AMS. Worth excluding common &#8220;mimickers&#8221;:<\/p>\n\n\n\n<figure class=\"wp-block-table is-style-stripes\"><table><thead><tr><th>Problem<\/th><th>Key differentiator<\/th><\/tr><\/thead><tbody><tr><td><strong>Dehydration<\/strong><\/td><td>dark urine, dry mucous membranes; symptoms resolve after 1 L electrolytes within 1\u20132 h<\/td><\/tr><tr><td><strong>Cold \/ sinus infection<\/strong><\/td><td>runny nose, sinus pain, fever; response to standard analgesics &#8220;as at sea level&#8221;<\/td><\/tr><tr><td><strong>Migraine<\/strong><\/td><td>pulsatile unilateral, aura, photophobia, migraine history<\/td><\/tr><tr><td><strong>Physical exhaustion<\/strong><\/td><td>resolves after 2\u20134 h rest, no other AMS features<\/td><\/tr><tr><td><strong>Hypoglycemia<\/strong><\/td><td>headache + tremor + sweating; resolves after carbs<\/td><\/tr><tr><td><strong>CO poisoning<\/strong> (tent!)<\/td><td>headache + nausea + drowsiness after time in closed tent with stove<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>Practical rule: if symptoms resolve after <strong>24 h rest at the same altitude + hydration + paracetamol<\/strong> \u2014 likely mild AMS or combined dehydration\/exhaustion. If they worsen or ataxia or resting dyspnea develops \u2014 assume HACE\/HAPE and initiate descent.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">When to descend \u2014 the golden rules<\/h2>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Descent is not failure<\/strong> \u2014 it is treatment. The only truly effective treatment for HACE and HAPE.<\/li>\n<li><strong>Do not ascend with any AMS symptoms<\/strong>. ICAR\/UIAA rule: &#8220;don&#8217;t ascend with symptoms&#8221;.<\/li>\n<li><strong>Descend 500\u20131000 m<\/strong> for worsening moderate AMS, <strong>immediately<\/strong> for suspected HACE\/HAPE.<\/li>\n<li><strong>Climb high, sleep low<\/strong> \u2014 acclimatization touch may go higher, but sleep lower.<\/li>\n<li><strong>The 300\u2013500 m rule<\/strong> \u2014 above 3000 m do not increase sleeping altitude faster. After every 1000 m climbed \u2014 rest day.<\/li>\n<li><strong>Never leave a sick person alone<\/strong>. Someone with AMS can progress to HACE within hours and be unable to call for help.<\/li>\n<\/ol>\n\n\n\n<h2 class=\"wp-block-heading\">Pharmacological prophylaxis \u2014 when it makes sense<\/h2>\n\n\n\n<p>In my opinion the best and healthiest approach to acclimatization is <strong>natural acclimatization without prophylactic medication<\/strong>. Drugs are often overused \u2014 part of the climbing community takes acetazolamide like candy, because &#8220;everyone does&#8221;. Not everyone should.<\/p>\n\n\n\n<p>Pharmacological prophylaxis is worth considering when:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Previous episode of severe AMS, HACE or HAPE (unless we can identify a specific acclimatization error then)<\/li>\n<li>Forced rapid ascent (&gt;500 m sleeping\/day above 3000 m) due to logistics<\/li>\n<li>Expedition to regions without evacuation options (rare today, occasional on remote 6000-ers)<\/li>\n<\/ul>\n\n\n\n<p>Most frequently used drugs in AMS prophylaxis and treatment:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Acetazolamide (Diamox \/ Diuramid)<\/strong> \u2014 first-line drug. Prophylactic dose 125 mg twice daily, therapeutic 250 mg twice daily. Start 24 h before reaching new altitude. Details: <a href=\"\/en\/diamox-acetazolamide-dosing\/\">Diamox \u2014 prophylactic and therapeutic dosing<\/a>.<\/li>\n<li><strong>Dexamethasone<\/strong> \u2014 first-line in HACE <em>treatment<\/em> (8 mg single dose, then 4 mg every 6 h), rarely in prophylaxis.<\/li>\n<li><strong>Nifedipine \/ nitrendipine<\/strong> \u2014 in HAPE <em>treatment<\/em> (20\u201330 mg every 8 h). Not classic AMS prophylaxis.<\/li>\n<li><strong>Ibuprofen<\/strong> \u2014 600 mg three times daily has documented RCT prevention effect for AMS, weaker than acetazolamide. Alternative for sulfonamide-intolerant patients.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Acclimatization \u2014 how to do it properly<\/h2>\n\n\n\n<p>Acclimatization is a series of physiological changes enabling tolerance of lower oxygen availability. Key processes: increased minute ventilation, rising red cell count, improved muscle perfusion, mitochondrial density. Full acclimatization to a given altitude takes 2\u20134 weeks and persists up to 6 weeks after return to lowlands \u2014 every subsequent expedition requires fresh acclimatization.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Practical acclimatization rules<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Slow ascent<\/strong>: maximum 300\u2013500 m sleeping altitude\/day above 3000 m.<\/li>\n<li><strong>Rest day<\/strong> after every 1000 m gained: sleep at the same altitude, day walk higher for acclimatization touch (&#8220;climb high, sleep low&#8221;).<\/li>\n<li><strong>Hydration 3\u20136 L\/day<\/strong>. Monitor urine \u2014 clear or straw = OK, darker = add electrolytes and drink more.<\/li>\n<li><strong>Avoid alcohol<\/strong> during acclimatization \u2014 it depresses the respiratory center and deepens nocturnal hypoxia.<\/li>\n<li><strong>Avoid strong sedatives<\/strong> \u2014 same reason.<\/li>\n<li><strong>Monitor symptoms daily<\/strong> \u2014 pulse oximetry morning and evening + Lake Louise Score.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Pre-acclimatization in hypoxic tents<\/h3>\n\n\n\n<p>Some people sleep or train in hypoxic tents as preparation. Meta-analyses show some effect \u2014 particularly with sleeping at simulated altitudes of 2000\u20132500 m for 2\u20134 weeks, minimum 14 h\/day. Logistically expensive but worth considering before fast expeditions (e.g. weekend Mont Blanc, time-limited Aconcagua).<\/p>\n\n\n\n<p>Honestly \u2014 this is a tool I would use in preparation for extreme-altitude expeditions. Limitation: hypoxic tents do not fully reproduce mountain conditions as they manipulate oxygen concentration, not atmospheric pressure. Oxygen molecules are not &#8220;dispersed&#8221; as in reality.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">High-risk groups<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Previous AMS\/HACE\/HAPE episode<\/strong> \u2014 re-entry HAPE risk on every subsequent expedition.<\/li>\n<li><strong>Children<\/strong> \u2014 higher risk of rapid HAPE development. Most pediatric organizations advise against treks above 3500 m in children &lt;10\u201312 years.<\/li>\n<li><strong>Cardiac and pulmonary disease<\/strong> \u2014 uncontrolled heart failure, severe COPD, pulmonary hypertension are contraindications to expeditions above 3500 m.<\/li>\n<li><strong>Anemia<\/strong> \u2014 Hb &lt;11 g\/dL in women, &lt;12 g\/dL in men \u2014 reduced oxygen transport capacity.<\/li>\n<li><strong>Diabetes<\/strong> \u2014 glycemic control is harder at altitude (absorption changes, altered energy demand).<\/li>\n<li><strong>Pregnancy<\/strong> \u2014 no clear guidelines, most physicians advise against trekking above 3000\u20133500 m due to potential fetal hypoxia effects.<\/li>\n<\/ul>\n\n\n\n<p>Each of these situations requires <strong>individual consultation with an expedition medicine physician<\/strong> \u2014 not a &#8220;family doctor who writes a certificate&#8221;. The expedition plan should consider specific route, pace, evacuation options, and pharmacological reserves.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">High-altitude first aid kit essentials<\/h2>\n\n\n\n<p>Minimum kit for altitude illness (beyond the general first aid kit \u2014 see <a href=\"\/en\/expedition-medical-kit\/\">complete expedition medical kit guide<\/a>):<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Pulse oximeter<\/strong> + spare batteries (laminated card with SpO\u2082 norms at various altitudes)<\/li>\n<li><strong>Acetazolamide (Diuramid) 250 mg<\/strong> \u2014 at least 20 tablets for a 2\u20133 week expedition<\/li>\n<li><strong>Dexamethasone<\/strong> \u2014 tablets + pre-drawn IM injection (lateral thigh) \u2014 HACE rescue kit<\/li>\n<li><strong>Nifedipine<\/strong> 20 mg (sustained-release) \u2014 HAPE rescue kit<\/li>\n<li><strong>Paracetamol \/ ibuprofen \/ metamizole<\/strong> for headache<\/li>\n<li><strong>Rescue oxygen cylinder<\/strong> (on larger expeditions) or base camp access<\/li>\n<li><strong>Laminated Lake Louise Score<\/strong> \u2014 works without batteries<\/li>\n<\/ul>\n\n\n\n<p>Note: acetazolamide, dexamethasone and nifedipine are <strong>prescription-only<\/strong> drugs. Before the expedition, meet with an expedition or travel medicine physician \u2014 a good rescue plan is one you know, with drugs on hand that you can administer.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Altitude sickness myths<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">&#8220;I&#8217;m fit, I won&#8217;t get sick&#8221;<\/h3>\n\n\n\n<p>Aerobic fitness does not translate to altitude sickness immunity. We see athlete-machines who push summit ascents at high pace and exactly for this reason fall ill faster \u2014 the stressed body acclimatizes worse. Humility toward altitude applies to everyone regardless of VO\u2082max.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">&#8220;If I go slowly, there will be no problem&#8221;<\/h3>\n\n\n\n<p>Slow walking pace during the day \u2260 slow acclimatization. What counts is sleeping altitude, not trail pace. You can crawl for 10 h and still exceed 500 m\/night rule \u2014 result: AMS in the evening.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">&#8220;Acetazolamide masks symptoms \u2014 it&#8217;s dangerous&#8221;<\/h3>\n\n\n\n<p>A myth common in Eastern European climbing circles. Acetazolamide does not &#8220;mask&#8221; symptoms \u2014 it genuinely accelerates acclimatization (increases minute ventilation via metabolic acidosis). RCT meta-analyses show reduced AMS and HAPE frequency with prophylaxis in at-risk individuals. Not a miracle, but a tool with documented efficacy.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">&#8220;Sherpas are AMS-immune because they are strong&#8221;<\/h3>\n\n\n\n<p>Sherpas are <strong>adapted<\/strong>, not acclimatized. Adaptation is multi-generational genetic change (increased NO production, higher SpO\u2082 at given altitude, more efficient mitochondria). We, lowland dwellers, can achieve only acclimatization \u2014 a short-term process. You cannot &#8220;become a Sherpa&#8221; in 3 weeks.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Frequently asked questions<\/h2>\n\n\n<div id=\"rank-math-faq\" class=\"rank-math-block\">\n<div class=\"rank-math-list \">\n<div id=\"faq-q-ams-en-1\" class=\"rank-math-list-item\">\n<h3 class=\"rank-math-question \">At what altitude does altitude sickness start?<\/h3>\n<div class=\"rank-math-answer \">\n\n<p>First AMS symptoms may appear from 2000\u20132500 m in susceptible individuals, but statistically significant incidence (20\u201350%) starts at 3500 m. Above 5000 m it is hard to find someone without any symptoms \u2014 headache and poorer sleep at this altitude are normal. HACE and HAPE most often develop above 3500\u20134000 m.<\/p>\n\n<\/div>\n<\/div>\n<div id=\"faq-q-ams-en-2\" class=\"rank-math-list-item\">\n<h3 class=\"rank-math-question \">Does Diamox really work prophylactically?<\/h3>\n<div class=\"rank-math-answer \">\n\n<p>Yes. RCT meta-analyses show significant reduction in AMS incidence (30\u201350%) with 125 mg twice daily started 24 h before altitude exposure. Mechanism: carbonic anhydrase inhibition \u2192 metabolic acidosis \u2192 compensatory hyperventilation \u2192 better oxygen delivery. This is not marketing \u2014 it is documented pharmacology. Dosing details: \/en\/diamox-acetazolamide-dosing\/.<\/p>\n\n<\/div>\n<\/div>\n<div id=\"faq-q-ams-en-3\" class=\"rank-math-list-item\">\n<h3 class=\"rank-math-question \">How fast must descent happen in HAPE or HACE?<\/h3>\n<div class=\"rank-math-answer \">\n\n<p>Immediately. In HACE every hour of delay increases mortality risk \u2014 the brain is losing oxygen. In HAPE the patient literally drowns in their own fluids. Target: at least 500\u20131000 m lower. Helicopter evacuation preferred; if impossible, on foot with escort (in HAPE seated position, in HACE supine with head elevated). Drugs (dexamethasone, nifedipine, oxygen) buy time \u2014 they do not replace descent.<\/p>\n\n<\/div>\n<\/div>\n<div id=\"faq-q-ams-en-4\" class=\"rank-math-list-item\">\n<h3 class=\"rank-math-question \">Does hypoxic training prevent AMS?<\/h3>\n<div class=\"rank-math-answer \">\n\n<p>Partially. Meta-analyses show effect with hypoxic tent sleep at simulated 2000\u20132500 m for minimum 14 h\/day over 2\u20134 weeks before expedition. Short intermittent exposures (type &#8220;one-hour chamber session&#8221;) have weak or no protective effect against real-altitude AMS. Treat pre-acclimatization as an adjunct, not a substitute for gradual ascent.<\/p>\n\n<\/div>\n<\/div>\n<div id=\"faq-q-ams-en-5\" class=\"rank-math-list-item\">\n<h3 class=\"rank-math-question \">How does AMS differ from HAPE and HACE?<\/h3>\n<div class=\"rank-math-answer \">\n\n<p>AMS is the mild form \u2014 headache + nausea + fatigue. Reversible, not directly life-threatening. HACE is cerebral edema \u2014 the key symptom is ataxia (loss of balance) and confusion, SpO\u2082 often &lt;50%. HAPE is pulmonary edema \u2014 dyspnea at rest, cough with bloody\/pink sputum. HACE and HAPE are life-threatening emergencies requiring immediate evacuation; AMS only requires rest at the same altitude and possibly medication.<\/p>\n\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n\n\n<h2 class=\"wp-block-heading\">References<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Luks AM, Auerbach PS, Freer L, et al. <em>Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Acute Altitude Illness: 2019 Update<\/em>. Wilderness Environ Med. 2019;30(4S):S3\u2013S18.<\/li>\n<li>Luks AM, Ainslie PN, Lawley JS, Roach RC, Simonson TS. <em>Ward, Milledge and West&#8217;s High Altitude Medicine and Physiology<\/em>, 6th ed. CRC Press, 2021.<\/li>\n<li>Hackett PH, Roach RC. <em>High-altitude illness<\/em>. N Engl J Med. 2001;345(2):107\u2013114.<\/li>\n<li>Hidalgo R et al. <em>High Altitude Medicine: A Case-Based Approach<\/em>. Springer, 2023.<\/li>\n<li>B\u00e4rtsch P, Swenson ER. <em>Acute high-altitude illnesses<\/em>. N Engl J Med. 2013;368(24):2294\u20132302.<\/li>\n<\/ul>\n\n\n\n<p><em><strong>Disclaimer:<\/strong> This article is for informational purposes only and does not replace individual medical consultation. In life-threatening situations on expedition, call 112, TOPR 601 100 300, GOPR 985 (Poland) or your local mountain rescue.<\/em><\/p>\n\n","protected":false},"excerpt":{"rendered":"<p>Mountain medicine doctor explains AMS, HAPE and HACE: symptoms, Lake Louise Score, acetazolamide prophylaxis, 300 m rule and acclimatization \u2014 everything you need before a high-altitude expedition.<\/p>\n","protected":false},"author":2,"featured_media":743,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[],"class_list":["post-1109","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-aktualnosci"],"_links":{"self":[{"href":"https:\/\/medycyna-gorska.pl\/en\/wp-json\/wp\/v2\/posts\/1109","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/medycyna-gorska.pl\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/medycyna-gorska.pl\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/medycyna-gorska.pl\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/medycyna-gorska.pl\/en\/wp-json\/wp\/v2\/comments?post=1109"}],"version-history":[{"count":2,"href":"https:\/\/medycyna-gorska.pl\/en\/wp-json\/wp\/v2\/posts\/1109\/revisions"}],"predecessor-version":[{"id":1125,"href":"https:\/\/medycyna-gorska.pl\/en\/wp-json\/wp\/v2\/posts\/1109\/revisions\/1125"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/medycyna-gorska.pl\/en\/wp-json\/wp\/v2\/media\/743"}],"wp:attachment":[{"href":"https:\/\/medycyna-gorska.pl\/en\/wp-json\/wp\/v2\/media?parent=1109"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/medycyna-gorska.pl\/en\/wp-json\/wp\/v2\/categories?post=1109"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/medycyna-gorska.pl\/en\/wp-json\/wp\/v2\/tags?post=1109"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}