Altitude Sickness from Indian Metros — Diamox, Acclimatisation and Hospital List for 2026
By Reyansh Mehta (Reyansh Mehta covers hill stations across the Indian Himalayas — Manali, Kashmir, Ladakh, Sikkim, Spiti — with a focus on flights, road conditions, altitude acclimatisation and permit rules. He's spent 90+ days above 3,500m in the last five years.) · Published · 12 min read
Most Indian metro residents flying to Leh, Spiti or Gurudongmar are sea-level dwellers jumping to 3,500m or higher in 90 minutes. Here is the practical 2026 guide to altitude sickness, Diamox, acclimatisation and the hospital network across the Indian Himalayas.
What this article covers
Why metro Indians are uniquely vulnerable to altitude
Recognising AMS — symptoms, timing, severity scoring
Diamox protocol — dose, timing, side effects
Acclimatisation protocols — fly-in vs drive-in approaches
The 1,000m rule and other ascent guidelines
Hospital and medical infrastructure across the Indian Himalayas
What to pack and what to carry — the high-altitude kit
Pre-existing conditions — who should not go to high altitude
When to descend immediately — the non-negotiable rules
Practical altitude itinerary examples — what good looks like
Frequently asked questions
Should I take Diamox before flying to Leh?
Yes, Diamox is recommended for fly-in arrivals at Leh. The standard prophylactic dose is 125mg twice daily, starting 24 hours before your flight and continuing for the first 48-72 hours at Leh. Speak to your GP for a prescription 2 weeks before your trip. Do not start Diamox for the first time on the morning of the flight without medical advice. If you have sulpha drug allergy or other contraindications, you cannot take Diamox and need alternative acclimatisation strategies including extra rest days.
How long does altitude sickness last?
Mild AMS typically resolves within 24-48 hours with rest, hydration and no further altitude gain. Moderate AMS may take 48-72 hours to fully resolve. If symptoms persist beyond 48-72 hours without improvement, or worsen despite rest, descent to lower altitude is required. HAPE and HACE are emergencies requiring immediate descent regardless of duration. Acclimatisation is a real physiological process — by day 3-5 at altitude, most acclimatised travellers feel close to normal even at 3,500m.
Can children fly to Leh safely?
Children above 5 years generally tolerate altitude well with the same acclimatisation protocols as adults. Children under 2 years should not be taken above 2,500m. Children 2-5 years require careful supervision and ideally slower ascent (consider road journey rather than direct flight). Watch for behavioural changes (irritability, sleep disturbance, decreased activity, loss of appetite) as these may be the earliest signs of AMS in children who cannot articulate their symptoms. Consult a paediatrician before any trip above 3,000m with children under 8 years.
Is alcohol safe at high altitude?
Strongly avoid alcohol for the first 48-72 hours at altitude. Alcohol depresses respiratory drive which is exactly what your body needs more of at altitude, increases dehydration which worsens AMS symptoms, and interferes with sleep quality at a time when sleep is already disrupted. After full acclimatisation (day 4+ at altitude), moderate alcohol is generally tolerated but limit to 1-2 drinks rather than typical sea-level intake. Heavy alcohol consumption at altitude is genuinely dangerous regardless of acclimatisation status.
What is the safe rate of ascent at high altitude?
Above 2,500m, do not increase your sleeping altitude by more than 1,000m per day. Daytime exposure to higher altitude is acceptable provided you descend for sleep. Build a rest day every 3-4 days of active high-altitude travel. For fly-in arrivals (which violate the 1,000m rule by definition), the first 24-36 hours of total rest at arrival altitude is the substitute acclimatisation strategy. Never attempt the highest altitude of your trip on the first day of arrival.
Are there hospitals at Leh and Manali for altitude emergencies?
Yes. Leh has the Sonam Norboo Memorial Hospital (SNM Hospital) with a dedicated high-altitude medicine unit, oxygen, hyperbaric chamber and helicopter evacuation coordination. The Indian Army Hospital at Leh also handles civilian altitude emergencies. Manali has the District Hospital and Indus Hospital with basic emergency care including oxygen, plus Apollo Hospital at Naggar for more serious cases. For severe cases requiring tertiary care, helicopter evacuation to Chandigarh PGI or AIIMS Delhi is arranged through these hospitals.
What does a pulse oximeter tell me at altitude?
A pulse oximeter measures peripheral oxygen saturation (SpO2). At sea level, normal SpO2 is 98-100 percent. At 3,500m (Leh) without altitude sickness, typical SpO2 is 88-92 percent. SpO2 below 80 percent at altitude is concerning and below 75 percent is alarming, especially if associated with symptoms. The device is useful for monitoring trends rather than absolute values — a sudden drop in SpO2 with worsening symptoms is a red flag warranting medical attention. The small finger-clip devices cost 800-2,500 rupees and are worth carrying for high-altitude trips.
Can I get altitude sickness even if I have been to high altitude before without problems?
Yes. Previous successful high-altitude exposure does not guarantee future safety. AMS risk depends on the current ascent profile, hydration status, fatigue level, recent illness, and many variables that differ between trips. Many experienced high-altitude travellers have had unexpected AMS episodes on trips where they expected to be fine. Maintain the same acclimatisation discipline regardless of prior experience — gradual ascent, hydration, no alcohol initially, Diamox if your doctor approves, and willingness to descend if symptoms develop.