Short Trek for High Altitude

Dilliwala

As a non-trekker and non-mountaineer, I'm puzzled about something re acclimatisation at and over 10000 ft -

1. Driving from Manali to Rohtang La, one goes from 6500 ft to 13000 ft in 90 mins max. Why didn't I get any AMS or acclimatisation prob? Didn't even feel light-headed. And thousands of people do it every year.

2. Driving from Rohtang to Leh, one crosses 15000 and 17000 ft passes. I'm aware some people get unwell or sick, but never heard of anyone dying. Nor do vehicles stop along the way for acclimatisation of occupants. Why is climbing different? Is it becos of the severe physical exertion?

I'm planning a Manali-Keylang v.v. drive in 2 months, and mulling with the idea of extending it to Leh, if things work out, so interested to know what to expect at 17000 ft.

vistet

I´m not quite sure on how reach the Rothang that fast , but I´m aware of more extreme examples. It is for example perfectly legit to bring up people in a non-pressurised aircraft from sea level to 4000 meters in under ten minutes.
Provided that you immediately throw them out at that altitude (out of sight , out of mind ) . That´s what sky divers do. The pilot on the other hand is not allowed to faff about at that altitude without oxygen ; I think the regulations says max 15 minutes without oxygen mask.

The point would be this is : it´s not just about the max altitude reached , but time spent there.Yes , thousands do it every year - and everyone who faces a lengthy delay in the high sections is in a potentially dangerous situation.


If you look at the elevation curves for the roads to Leh , you can imagine another curve : each high point on the curve is mirrored by a low point in oxygen content in the blood. The effects of having a low oxygen content are cumulative : forget for a moment the isolated spikes , and look at the surface area of the diagram and you´ll realise that a night in Sarchu is a lot more worse than going over the Rothang than the three hundred meters of altitude difference tells us.

If this was a static condition then we would just gradually progress for the worse with increased altitude , but the body can adapt to some degree , given reason. The low points in oxygen saturation that we can handle are the reason for the acclimatisation process - I´m willing to wager that if the tunnel under the Rothang becomes reality travellers will get worse AMS scores on the second half of the road.

Exertion is no way a requisite for fatal AMS, and a stop would anywhere after Darcha would only worsen the situation. The large majority come down to Leh´s altitude before effects cumulate. On the other hand I heard of a young girl who died enroute Lhasa-EBC just last week , and Steven Bezrukcha recaps in his book of another traveller who went more or less straight from the jeep to the Gamow bag , and didn´t survive the second night without it. The altitudes involved are in no way different from what you see on the roads of Ladakh.

You may also note that the Indian Army takes the issue seriously , and spend a lot more time in transferring their troops to Ladakh , probably because they want them in working order any given day. The railroad workers for new train line to Lhasa worked under similar regulations - minimum four days to reach worksites as high as the Baralacha La.

My personal experience in this is that I´ve seen someone coming close to death - prospects are bleak once you go unconscious.

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AvidTrekker

What is your net gain in sleeping altitude is the key question. The effects have been observed to start somewhere around 9000 to 10000 feet. As a rule of thumb one should not sleep at an altitude higher than 1500 to 1800 feet in a single day. Again, if one does three days in a row with a consistently maximum sleeping altitude gain, then one must rest for an entire day.

Sleep at Keylang and you won't feel a thing. Sleep at Sarchu or Pang and be prepared.... for whatever AMS symptoms.... [headache at the very least]

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Dilliwala

Wow! Not sure I understand all of the technical stuff (yet), but thanks for your replies.

It's perfectly poss to drive up from Manali to Rohtang in 90 mins. I omitted to add that I stopped for 15 min at Marhi (3300 m) on the way, Drove thru to Gramphu and spent about 25 min at Rohtang on the way back. 30 min again at Marhi.
But some taxi drivers just drive non-stop, up or back.

Sent by dialup from rainy Munsyari - all of 2300 m high! Panchchuli looked great this morn.

capt_mahajan

No need to rub it in

Enjoy. Even though I am green.