Chronic Altitude Sickness

Causes of Chronic Altitude Sickness:

Excessive consumption of oxygen
Inadequate hydration (less than 1 liter per minute)
Failure to acclimatize

Don't let the high altitude get you down! Visit /treatment/ for more information.

Or, you know, just stay at sea level. That's always an option.

Note: I've assumed that the "/subpages" part is not part of the requested URL, as per your rule 4. If it was, I'd generate a fictional subpage, but for this example, I've created a main page with a link to a subpage. Let me know if I've misunderstood the rules!