Acclimatizing to Altitude

2012-09-03 • SEND FEEDBACK |

Related: acclimatizing to altitude, health, Inyo National Forest, peak bagging, training, White Mountains

Summitting 14,252' White Mountain Peak, I felt no particular issue from the extreme altitude; I had been sleeping and spending the past 9 days at 10,500 - 12,500' of elevation (3200 - 3810 meters).

There are “train low sleep high” studies out there which can be easily misconstrued and misunderstood— “1-2% gains by training low and sleeping high”.

Such stuff is nonsense for races like the Everest Challenge where the race averages* 7,000 feet (2100m) or more in elevation. You get a LOT more than 1-2% by acclimatizing to such a challenge.

To put a number to it, after 9 days of acclimatizing, I estimate a 20-30% gain in the power (watts) that I can sustain at very high altitude (11,000' on up), as compared with the first day. Or literally, a 100% gain compared to what I’ve felt from going to sea level to 13,000' in one day, where physical and mental function has been severely impaired even descending (“brain fade” from low oxygen).

In short, if the race is at high altitude, get your body up there high a week in advance (or more) and spend 7-10 days at 10,000' or so prior to the race. Descend the day prior to the race, sleep relatively low, eat well and be ready. Your body will have increased its ability to deliver oxygen to muscles: perfectly legal and appropriate “blood doping by acclimatization”. All sorts of physiological adaptations occur.

My approach probably works for me because I have an exceptional aerobic capacity to begin with, after years of intensive training; my suggestions below are targeted at those in exceptional aerobic/athletic condition to begin with, not weekend athletes.

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While in the White Mountains recently for 10 days, I monitored my physiology at altitude. Here is my executive summary of how I adjust to very high altitude:

In general, sleep requirements increase by 1-2 hours each night for the first 5 days or so.
First day— extreme fitness saves me, but I am breathing hard and can’t sustain hard efforts for long at 12,000' on up. Power surges (350 watts on up) are clearly impaired aside from short micro bursts (1-2 seconds) and mini bursts (5-10 seconds). More than that— forget it.
Day 2-3— noticeable improvements, but not at all feasible to sustain mini power bursts for more than about 10 seconds.
First 3 days awake at night with sensation of having stopped breathing, have to breathe hard for a few minutes to feel normal (sleeping at 11,800').
Day ~5— very substantial and noticeable ability to sustain power, but still impaired.
Day ~7— while not sea-level ability, power is feeling strong again; much improved ability to sustain 5-10 minute harder efforts.
Days ~9-10— Able to sustain solid power all the way to 14,252 feet.
No amount of acclimatization can deliver the same power as sea level; there is just not enough oxygen per breath for the aerobic system to contribute to the extent it can at sea level, or for waste byproducts to be metabolized away as quickly (e.g. lactic acid). The anaerobic system has to make up the difference, which means lower overall power which can be sustained for less time.

It is certainly in my plans to prepare the week before the 2012 Everest Challenge by adjusting to altitude as per above.

* Average elevation is not a clear-cut concept; to be realistic it should compute elevation averaged at one second samples, not evenly spaced distance samples from a map; the rider is moving much more slowly on the steep high-elevation grades and hence spends more time at higher elevations because of lower speed.

At the summit of White Mountain Peak at 14,252 elevation, August 16 2012
Riding Moots Mooto X YBB 29er
(Photo by Allen Kost of Redding, CA)

William P writes:

I thought I would comment on your reference of "sleeping high and training low" as a means acclimatizing to performing better in high altitude conditions.

I've been involved with high altitude mountaineering for a long time and the general meme in the climbing community is climb (train) high and sleep low. As climbers push up above 10,000 to 15,000 feet, they will generally do gear carries on one day to the next highest camp site, say 2,000 to 3,000 feet above their current camp and leave gear, but return to sleep that night at the lower camp.

The body responds to the brief altitude stimulus by continuing to accelerate red blood cell growth, but at a lower altitude that enables the climber to sleep better due to higher oxygen concentrations at the lower camp site. This is specifically done to mitigate known risks like sleep apnea, HAPE and HACE that are prone to occur if you advance altitude too quickly and remain there. Improved sleeping conditions and by extension, rest, understandably postions climbers to better handle the stresses of pushing upward over the course of the climb.

It may be different for cycling, but I thought I might mention it.

WIND: Everyone needs to know their own body and their own limits, my approach works for me quite well, but some athletes of any sport might need much more time to acclimate by adjusting a few thousand feet at a time— I don’t need such a delay, at least not for anything up to 12,000'. But I have seen 20-somethings puking their guts out at 12,000' on Mt Whitney, and pot-bellied climbers probably won’t fare so well no matter what.

Context matters too— cyclists do not ride to 12,000', then camp at 14,000, then assault a 20,000' peak. In this case, the context is quite the reverse: plenty of time at fairly high altitude to adjust, then a “peak attempt” (a cycling race) that is 5000-6000 feet lower in altitude.

The main issue is a practical one: it’s an inconvenient 2-hour round trip (at least) over rugged roads in/out of my favorite areas and to where? A hot lowland... and I want to enjoy the mountains!