Altitude sickness has taught me two important insights about speed and trends, which can be applied to software development projects (and probably many other areas as well).
After trekking above approximately 3,000 meters one has to take care not to climb too fast. The general rule is not to ascend more than 300 meters daily to acclimatise.
If your organism does not adapt to the height you reached, several symptoms appear (headache, fatigue, stomach illness, dizziness, and sleep disturbance).
This once happened to me in Nepal. The symptoms usually disappear within couple of hours. However, in some cases they may be getting worse, especially if you climbed significantly more than 300 meters within a day.
Altitude sicknes is quite a simple illness. If a patient is feeling worse and worse the end is always the same – death 😦 The only reliable treatment is to descend.
The first general thing I have learnt from altitude sicknes is existence of hard limit on velocity. Attempting to get above this limit is asking for trouble.
This applies to projects and speed of development as well. I like to keep that in mind when planning software development releases. Usually there is hardly anything we can to quickly achieve higher output (I am not talking about long-term improvements here) and the only reasonable option is cutting down on requirements.
Moreover, the way altitude sickness develops and comes away shows that it is all about the trends.
For instance, a percentage of code coverage in your project is relevant, but it is more important whether it is increasing or falling. The same applies to more general matters like quality, moods, financial situation and so on.
If we are on the wrong side of the trend, doing nothing and just waiting for better time to come will not help, exactly like in the case of sickness getting worse and worse.
All in all, I find those lessons on velocity limit and trends very useful – much often than in the high mountains.