Around 6000m acclimatised climbers may expect to feel well, have reasonable appetites, sleep normally and be capable of carrying loads of 20-25 kilos on easy ground. Ascent rates comparable to those on Alpine routes have been well documented over many years. Despite this, technical climbing of a high standard has been done and heavy loads have been carried, though well under 20 kilos should be aimed at. Ascent rates will vary enormously depending on terrain, but 300-400m a day is a very reasonable achievement. Deterioration Deterioration becomes increasingly apparent after several nights at 7000m.
Weight loss is profound.
Apathy also sets in, adding to the difficulties of cooking, which usually takes many hours even in ideal circumstances. Sleep becomes intermittent and, because of oxygen lack, cold is felt more even in the warmest of sleeping bags. The effects of deterioration become marked after 4 or 5 days and unless trapped by weather it is advisable not to stay much above 7000m for longer periods. There is little to be gained from attempting to set an altitude duration record by waiting for several days for weather to clear, because it is unlikely that you will have the energy in reserve to make use of it. Recovery from high altitude deterioration is a gradual process which can only take place at altitudes well below 6000m.