I'll never forget my first encounter with altitude sickness during a trek in Nepal. One minute I was admiring the Annapurna range, the next I was vomiting behind a rock with a headache that felt like an ice pick through my skull. That experience taught me why knowing about the three stages of altitude sickness isn't just trivia - it could save your life.
What Exactly Is Altitude Sickness?
Altitude sickness - doctors call it Acute Mountain Sickness (AMS) - happens when your body rebels against low oxygen levels at high elevations. It usually kicks in above 8,000 feet (2,400 meters), especially when you ascend too quickly. Your lungs literally can't grab enough oxygen molecules out of the thin air, and all hell breaks loose internally.
Here's something most articles won't tell you: Even fit people get nailed by altitude. I watched a marathon runner collapse at 11,000 feet while a chain-smoking 60-year-old strolled past him. Your fitness level has shockingly little to do with susceptibility. Genetics and ascent rate matter way more.
The Critical Question: What Are the 3 Stages of Altitude Sickness?
When people ask what are the three stages of altitude sickness, they're usually imagining something linear. Reality is messier. Symptoms can overlap, progression varies wildly, and ignoring early signs invites disaster. Here's the breakdown:
Stage 1: Mild AMS (The Warning Shot)
Typically hits 6-12 hours after arriving at altitude. Think of this as your body yelling: "Hey dummy, slow down!" Symptoms include:
- Throbbing headache (the #1 symptom)
- Dizziness like you've had two martinis
- Nausea that comes in waves
- Fatigue disproportionate to activity
- Shortness of breath during minor exertion
- Weird, restless sleep patterns
During my Peru trip, I ignored my mild AMS headaches for two days. Big mistake. By day three, I couldn't keep water down. The golden rule? Never ascend higher with stage 1 symptoms.
Stage 2: Moderate AMS (Red Alert)
Now we're in dangerous territory. Symptoms intensify and new ones appear:
- Headaches that painkillers won't touch
- Violent vomiting (dry heaves if stomach's empty)
- Severe shortness of breath even at rest
- Coordination problems - can't walk straight
- Confusion or irrational behavior
- Bluish lips/nails (cyanosis)
Medical truth bomb: At this stage, descending immediately is non-negotiable. I've seen people argue they paid too much for their trek to quit. That mentality kills. You can lose consciousness within hours.
Stage 3: Severe AMS (Life-or-Death)
This splits into two deadly conditions requiring emergency evacuation:
| Condition | Symptoms | Timeframe | Action Required |
|---|---|---|---|
| HACE (High Altitude Cerebral Edema) |
- Hallucinations - Inability to walk straight - Paralysis - Unconsciousness |
Can develop in 12 hours | Immediate descent + oxygen + dexamethasone |
| HAPE (High Altitude Pulmonary Edema) |
- Gurgling breath sounds - Coughing pink froth - Extreme fatigue - Chest tightness |
Often appears at night | Immediate descent + nifedipine + oxygen |
When explaining what are the three stages of altitude sickness, this final phase terrifies people most. Rightfully so. HAPE killed a climber on my Denali expedition after he ignored wet coughs for two days. Don't be that person.
Critical Prevention Strategies That Actually Work
After suffering AMS multiple times, I've become religious about prevention:
Smart Ascending Strategies
| Altitude Range | Maximum Daily Ascent | Rest Days Needed |
|---|---|---|
| 8,000-10,000 ft | 1,000 ft per day | None if asymptomatic |
| 10,000-14,000 ft | 1,000 ft per day | Every 3-4 days |
| Above 14,000 ft | 500-800 ft per day | Every 2-3 days |
Pro tip: "Climb high, sleep low" actually works. Sleeping even 1,000 feet lower than your daytime max helps immensely.
Medications Worth Considering
- Acetazolamide (Diamox): Start 24hr before ascent (125mg twice daily). Causes tingly fingers but prevents headaches.
- Dexamethasone: Emergency use only for severe AMS. Masks symptoms dangerously.
- Avoid sleeping pills: They suppress breathing - terrible idea at altitude.
Hydration & Nutrition Hacks
Drinking enough matters, but overhydration causes hyponatremia (dangerously low sodium). Aim for urine the color of pale straw. Eat carb-heavy meals - they require less oxygen to metabolize than protein or fat.
Altitude secret: Garlic soup is the Andean remedy for soroche (their term for AMS). Whether it's the antioxidants or placebo effect, I've seen it work wonders in Peruvian hostels.
Treatment: What to Do When Symptoms Hit
Spotting where you fall in the three stages of altitude sickness dictates your response:
Stage 1 Action Plan
- Stop ascending immediately
- Rest with head elevated
- Hydrate with electrolytes
- Take ibuprofen for headache
- Consider acetazolamide if prescribed
If symptoms don't improve in 24 hours, descend 1,500-3,000 feet.
Stage 2 Emergency Protocol
- Descend immediately (minimum 3,000 feet)
- Use portable oxygen if available
- Take dexamethasone if prescribed
- Seek medical evaluation ASAP
Stage 3 Life-Saving Measures
For HACE/HAPE:
- Evacuate immediately (helicopter if possible)
- Use hyperbaric bag (Gamow bag) while waiting
- Administer oxygen continuously
- Medications: Dexamethasone for HACE, nifedipine for HAPE
I keep a Gamow bag on all high-altitude expeditions. At $3,000 it's pricey, but cheaper than a funeral.
Special Risk Groups: Who Gets Hit Hardest?
Certain people play altitude sickness on hard mode:
- Previous AMS sufferers: 60% chance of recurrence
- Heart/lung condition folks: Requires doctor clearance
- Kids under 8: Hard to recognize symptoms
- Rapid ascenders: Flying directly to high cities like Cusco or Lhasa
Pregnant women face special risks - most doctors recommend avoiding elevations above 12,000 feet entirely.
My hardest lesson? Jet lag + altitude = misery. After flying from New York to Kathmandu, I ascended too fast. The combination destroyed me. Now I always build in two low-altitude recovery days after long flights.
Altitude Sickness FAQ: Real Questions from Real Travelers
Can I drink alcohol at high altitude?
Bad idea. Alcohol dehydrates you and depresses breathing. Save the celebratory drinks for when you return to lower elevations.
Does drinking coca tea actually help?
Maybe. The caffeine provides mild symptom relief, but it's no substitute for proper acclimatization. Don't rely on it.
How long does altitude sickness last?
Mild cases resolve in 1-3 days with rest. Severe cases require descent and may take weeks to fully recover.
Is there a test to predict my risk?
No reliable test exists. Previous experiences are your best predictor.
Are oxygen bars effective for prevention?
Short-term placebo at best. The benefit vanishes once you leave the bar.
Can children develop altitude sickness?
Yes, and they often can't articulate symptoms well. Watch for unusual fussiness or lethargy.
Life-Saving Gear You Should Consider
Don't head into high country without these:
- Pulse oximeter: $20 device that measures blood oxygen saturation (SpO2). Below 85% signals trouble.
- Diamox: Prescription preventative medication
- Portable oxygen: Lightweight canisters for emergencies
- SAT phone/inReach: For emergency communication where cell service vanishes
Myth-Busting Common Altitude Misconceptions
| Myth | Reality |
|---|---|
| "Young fit people don't get altitude sickness" | Fitness doesn't prevent AMS - genetics and ascent rate matter more |
| "Drinking extra water prevents AMS" | Overhydration causes hyponatremia - balance is key |
| "You can 'push through' mild symptoms" | This is how moderate AMS becomes life-threatening |
| "Living at altitude makes you immune" | You lose acclimatization after 1-2 weeks at low elevation |
When to Cancel Your High-Altitude Plans
Some situations mean you should postpone:
- Active respiratory infection (even a cold)
- Uncontrolled heart/lung conditions
- Pregnancy (especially 3rd trimester)
- Recent heart attack or stroke
- Sickle cell trait (risk of crisis)
I once turned back from Kilimanjaro after developing bronchitis. Gut-wrenching but smart - three climbers got evacuated with HAPE that week.
Final Thoughts: Respect the Mountains
Understanding what are the three stages of altitude sickness transforms how you approach high elevation. It's not about fear - it's about preparation. I've climbed peaks across six continents, and every time I ascend, I mentally review these symptoms. Does it kill spontaneous adventure? Absolutely not. But it keeps you alive to adventure another day.
Most tragedies happen when people ignore stage 1 warning signs. Your summit photo isn't worth brain damage or death. Learn the stages of altitude sickness, prepare accordingly, and the mountains will reward you with experiences worth remembering.
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