### The Ultimate Guide to High-Altitude Travel: Mountain Passes, Acclimatization & Physical Effects

Traveling to high-altitude regions like Ladakh and Spiti is an incredible experience, but understanding how altitude affects your body is crucial. From breathtaking mountain passes to physiological changes, this guide covers everything you need to know about altitude adaptation, AMS prevention, and the impact on physical activity.

Major Mountain Passes & Their Altitudes

Manali to Leh

• Rohtang La – 3,978m

• Baralacha La – 4,850m

• Naki La – 4,739m

• Lachulung La – 5,059m

• Tanglang La – 5,328m

Srinagar to Leh

• Zoji La – 3,528m

• Fotu La – 4,108m

• Namika La – 3,700m

Leh to Nubra Valley

• Khardung La – 5,359m

Leh to Pangong Lake

• Chang La – 5,360m

Eastern Ladakh (Hanle Side)

• Umling La – 5,799m (One of the world’s highest motorable passes!)

Pangong Lake to Tso Moriri

• Rezang La – 5000m

• Tsaga La – 4635m

Leh to Zanskar (Padum)

• Singi La – 5,091m

• Sirsir La – 4,804m

Zanskar to Kargil

• Pensi La – 4,400m

Zanskar to Manali

• Shinku La – 5,090m

Manali to Kaza (Spiti)

• Kunzum La – 4,551m

Major Villages & Their Altitudes

• Manali – 2,050m

• Sissu – 3,120m

• Jispa – 3,200m

• Sarchu – 4,290m

• Pang – 4,650m

• Leh – 3,500m

• Diskit/Hunder (Nubra Valley) – 3,144m

• Pangong Lake / Merak – 4,225m

• Tso Moriri / Karzok – 4,522m

• Hanle – 4,500m

• Padum (Zanskar) – 3,670m

• Phuktal Gompa – 3,850m

• Chandrataal Lake – 4,250m

• Kaza – 3,650m

• Key Monastery – 4,166m

• Chicham – 4,150m

• Kibber – 4,270m

• Hikkim – 4,440m

• Komik – 4,587m

• Langza – 4,419m

• Dhankar – 3,894m

• Nako – 3,625m

• Tabo – 3,280m

• Chitkul – 3,450m

• Kalpa – 2,960m

• Shimla – 2,205m

How Walking Feels at Different Altitudes

Altitude	Walking Experience
100m	Effortless, normal.
1,000m	Barely noticeable difference.
2,000m	Slight fatigue on inclines.
3,000m	Moderate exertion feels like intense cardio.
4,000m	Frequent breaks needed even on flat ground.
5,000m	Very slow pace, exhaustion even when resting.
6,000m	Simple walking feels extremely difficult.
7,000m	Every step is exhausting, body weakens rapidly.
8,000m	Near impossible to walk without oxygen support.

Oxygen Levels & Breathing Impact

Altitude	Oxygen Availability	Breathing Impact
100m	~20.8%	Normal
1,000m	~17.3%	Slightly deeper breaths.
2,000m	~15.1%	Some shortness of breath.
3,000m	~14.3%	Faster breathing, slight fatigue.
4,000m	~12.7%	Heavy breathing, noticeable exertion.
5,000m	~11.3%	Very hard to breathe, slow movement needed.
6,000m	~10.0%	Severe breathlessness.
7,000m	~9.0%	Extreme hypoxia, body struggles for oxygen.
8,000m	~7.8%	"Death Zone" - Cannot survive long.

Acclimatization & Altitude Sickness Risk

Altitude	Acclimatization & AMS Risk
100m - 1,000m	No acclimatization needed.
2,000m	Mild AMS symptoms in sensitive individuals.
3,000m	High chance of AMS, headaches possible.
4,000m	1-2 days acclimatization needed.
5,000m	Slow ascent is necessary.
6,000m	AMS almost guaranteed without preparation.
7,000m	Severe altitude sickness risk, high risk of HAPE/HACE.
8,000m	"Death Zone" - Body deteriorates even with oxygen.

Heart Rate & Circulation at Altitude

• 100m - 1,000m: Normal heart rate.

• 2,000m: Slight increase in resting heart rate.

• 3,000m: Heart rate 10-20% higher than normal.

• 4,000m: Noticeably elevated, even at rest.

• 5,000m: Heart pounding even with minimal exertion.

• 6,000m: Heart working at max capacity for basic movement.

• 7,000m: Severe strain on the cardiovascular system.

• 8,000m: Heart cannot sustain activity for long without oxygen.

Hydration Needs at High Altitude

• 100m - 1,000m: Normal water intake.

• 2,000m: Slightly increased water needs.

• 3,000m: Hydration is crucial to prevent AMS.

• 4,000m: Increased dehydration risk due to cold, dry air.

• 5,000m: Frequent hydration required; dehydration worsens AMS.

• 6,000m: Water intake must be doubled due to extreme dryness.

• 7,000m: Severe dehydration occurs quickly; high water needs.

• 8,000m: Drinking water is difficult; dehydration accelerates exhaustion & AMS.

The Ultimate Guide to Preventing & Treating Altitude Mountain Sickness (AMS)

Why Does AMS Happen?

At higher altitudes:

• Oxygen levels decrease – You breathe harder, but your body still gets less oxygen.

• Blood oxygen saturation drops – Muscles, brain, and organs get less oxygen, leading to symptoms.

• Fluid buildup in the brain & lungs – In severe cases, AMS can turn into HAPE (High-Altitude Pulmonary Edema) or HACE (High-Altitude Cerebral Edema), both of which can be fatal.

How to Prevent Altitude Mountain Sickness

1. Acclimatize Properly

The golden rule of altitude travel: Ascend slowly.

• If going above 3,000m, increase your sleeping altitude by no more than 300-500m per day.

• Every 1,000m gained, take a rest day at that altitude before ascending further.

2. Stay Hydrated

• Drink at least 3-4 liters of water per day at high altitudes.

• Avoid excessive caffeine and alcohol, as they dehydrate you and worsen AMS symptoms.

3. Eat More Carbs

Your body needs more energy at altitude. A high-carb diet (rice, pasta, bread, fruits) helps with oxygen utilization.

4. Use the “Climb High, Sleep Low” Strategy

• During acclimatization, hike to a higher altitude during the day but sleep at a lower altitude at night.

• This allows your body to adjust without stressing it too much.

5. Avoid Overexertion

• Move slowly and steadily at high altitudes.

• Take frequent breaks, especially if you feel out of breath.

6. Take Preventive Medication (If Necessary)

• Acetazolamide (Diamox) helps speed up acclimatization by making you breathe faster.

• Start 125-250mg twice a day a day before ascent and continue for a few days.

• Gingko Biloba (a natural supplement) may help, but it’s not as effective as Diamox.

7. Recognize Early Symptoms & Take Action

Even if you follow all precautions, mild AMS can still happen. Catching symptoms early and responding properly prevents serious illness.

Symptoms of Altitude Mountain Sickness (AMS)

AMS symptoms usually start within 6-24 hours of reaching high altitude.

Mild AMS (Common, Not Dangerous)

✅ Headache✅ Dizziness✅ Fatigue✅ Nausea or loss of appetite✅ Difficulty sleeping

Moderate AMS (Needs Immediate Action)

⚠️ Worsening headache that doesn’t go away with painkillers⚠️ Vomiting⚠️ Feeling confused or disoriented⚠️ Difficulty walking in a straight line

Severe AMS – HAPE & HACE (Life-Threatening!)

🚨 HAPE (High-Altitude Pulmonary Edema) –

Lungs fill with fluid❌ Severe breathlessness, even at rest❌ Coughing up frothy, pink mucus❌ Chest tightness & blue lips/fingertips

🚨 HACE (High-Altitude Cerebral Edema) –

Brain swelling❌ Confusion, hallucinations❌ Severe headache & vomiting❌ Loss of coordination, stumbling while walking

🔴 If someone shows symptoms of HAPE or HACE, IMMEDIATELY descend to a lower altitude and seek medical help!

How to Treat Altitude Sickness

1. If You Have Mild AMS

• Stop ascending until symptoms improve.

• Drink plenty of water and eat high-carb foods.

• Take Ibuprofen or Paracetamol for headaches.

• If symptoms persist, consider taking Diamox (Acetazolamide).

2. If Symptoms Get Worse (Moderate AMS)

• Descend at least 300-500m immediately!

• Take Diamox 250mg every 12 hours if not already taking it.

• Rest for 24-48 hours before considering further ascent.

3. If You See HAPE or HACE Symptoms – Emergency Actions

🚨 DESCEND IMMEDIATELY! Go at least 1,000m down.🚨 Administer oxygen (if available).🚨 Use Nifedipine (for HAPE) or Dexamethasone (for HACE) if trained to do so.🚨 Seek emergency medical attention.

FAQs About AMS

Q1: Can AMS affect fit people?

Yes! Even the fittest athletes can get AMS. Fitness doesn’t prevent it—only proper acclimatization does.

Q2: Will AMS go away on its own?

Mild AMS can improve if you stay at the same altitude for 24-48 hours, but if symptoms worsen, you must descend.

Q3: Does oxygen help?

Yes, supplemental oxygen can relieve symptoms, but it’s a temporary fix. The best treatment is descending.

Q4: How long does it take to acclimatize?

Full acclimatization to 5,000m can take 1-2 weeks. The higher you go, the longer your body needs.

Q5: What’s the best way to avoid AMS?

• Slow ascent (300-500m per day above 3,000m).

• Stay hydrated & eat well.

• Recognize symptoms early and respond fast.