A little over nine hours after I'd left, I reached the fifth station again. The bright morning sunshine seemed like weeks ago, now that we were in thick cloud.
As I'd reached the bottom of the steepest part of the trail I'd started to get a headache and feel that I couldn't breathe in properly. I wondered if I was suffering from the altitude and in a moment of runaway hypochondria, decided I might have a high-altitude pulmonary oedema. At fifth station, the cloud was briefly so thick that I could not even see the buildings from a few metres away, but I found a stand selling coffee and bought one. Then I discovered that the symptoms of high altitude pulmonary oedema and the symptoms of mild caffeine deprivation are easily confused, and I soon felt great again.