[Rosie] - No oxygen. I was slowed down by the lack of it, but not reduced to gasping. The main effect was that I lost my appetite completely. I was there in March-April, so pre-monsoon. Overnight it was regularly down to about -20°C. During the day there was a lot of bright sunshine, but I reckon the shade temperature didn't get above freezing; it was fleece jacket, thick gloves & balaclava even when working quite hard and down clothing as soon as the sun set. Mera is the highest 'trekking peak' in the Himalaya, anything over 6500m is a 'climbing peak' even if there is no technical difficulty. However Aconcagua is higher and presents no technical difficulties and is only about 20km from a good motor road. It's probably the ultimate challenge for the non-climber.
(INJ) I'm further impressed. The pressure up there is about 42% of sea level pressure. Apparently the lack of oxygen causes considerable problems with cognitive tasks but as I imagine you weren't writing up a PhD up there it probably didn't matter. Well done! I could manage Leith Hill (965 ft) these days but probably not Snowdon (3561 ft) even if I called it Yr Wyddfa.
[Rosie] Acclimatisation helps a lot. We flew in to about 2400m and then walked in for about 10 days, mostly on the ‘walk high, sleep low’ principle, which got us to a camp at about 5300. We then did a short day up to 5800 and then a push to the top. I reckon the last 700m would have taken me a bit over 2 hours from sea level (I was fitter then), and actually took between 4 & 5 hours. We then dropped about 1500m, to below the previous 2 camps. As for cognitive impairment – I ‘lost’ a good part of the next day. I couldn’t remember much of it only a day or two later and have never been able to, even prompted by photos. Another interesting effect was that my tent companion went into a pattern of Cheyne-Stoking while asleep – disturbing when you first hear it, but common at altitude. Of course, one of the effects of the cold and low pressure is that the air is extremely dry – it was hard to drink enough, especially as water bottles exposed to the air froze. It’s the physically hardest thing I’ve ever done and I certainly couldn't do it now.
The good news is that we've discovered the cat is a mouser (one of the reasons for getting her). The bad news is finding this out obviously entailed a renewed incursion. We look forward to being woken up by her dropping half-dead mice on our faces and being shown how to kill them. Will need to look at the bait trays over the weekend to see where its been taken. Sometime over the next few weeks we're getting our floors repaired which should seal up some of the holes at least.