Mattresses / sleeping pads

It would more than likely be warmer if you could fit it inside your sleeping bag. My bag is too small for this exercise, so why don't you test it for us and give a report back on your findings. However, if you have a serious winter bag you probably wouldn't feel much of a difference - mine is a bit too hot for SA conditions so the other day at -8 deg I was actually sweating a bit and had to zip it open to cool down. With a typical 3 season bag I suspect it would make a difference. You have to consider how you sleep though, if you toss and turn around a lot I suspect it will not work so well as you might end up with the inflateable mattress on top of you

Hahahaha, Well I am doing a two nighter in Mzimkhulu wilderness area next weekend and expecting some sub zero temps, so wanted some thoughts
We cave first night and second night want to tent at altitude, weather permitting...

The bag and mat have the same mummy shaped profile so it does fit with me inside the bag and some room to maneuver (not much tho). Even though I was camped out in the lounge it was the most comfortable I've slept ever in a bag

Thanks guys will leave feedback here on return and some GPS coordinates for one or two caves we might be visiting.

I wish I had read this before last weekends hike,plus you will slip off the mattress if the ground is not level.

I tried last night, put the K-way compact inside the bag, and the inner in between, but it was very uncomfortable. Mattress pulls the bag tight over the top of you, and the bag tries to pull up the sides of the mattress. So I suppose it depends on the individual's set-up.
Related question, I have cut 2 section of foam mat about 600mm long, to go under the hip section of the K-way Compact self-inflating mattress, but still battle with sore hips during the night. (Can't seem to sleep on my back).
Any suggestions, except a new mattress?
Thanks

Try inflate the pad more. Try different leg positions, I often find I can relieve pressure on my hips that way

Get a thicker inflatable mattress like the one from JR Gear, think it is about 9cm thick.
Alternatively, sleep on these more often so you get used to the feeling. Doesn't matter what I do, I still don't sleep as well in the Berg as I do at home - other people snoring, hard mattress, body sore and tired from a tough days hike, having to get up for a pee, the effects of altitude, weather disruptions (like sleeping in a 100km/h + wind and worrying abouth the very immediate future of my tent) etc. etc. If I can just stay asleep and not wake up intermittendly I wouldn't even notice my sore hips I reckon.

I've got the JR Insulated Core Mummy (as well as 2x FA Ultralight self-inflating). The JR is a lot more admin to inflate and deflate. Takes up slightly less space though

Not sure if anyone is using a pump for their inflatible mattress. I also have the JR Gear Insulated Traverse Core. A homemade pump:

Ha, very cool. I wouldn't use a rubbish bag like that, plastic too thin and liable to tear. I don't like the valve on my JR Gear pad though, will try come up with something similar.

Captain, how have you found the JR pad? I haven't yet had a chance to use mine in cold weather

All I can say is I've been sleeping on 1x5mm thick foam pad since I've started hiking.
I would have to force myself to sleep on my back but always woke up on my side feeling sore. I will attest that weighing less helps. I'm heavier now than I was a year ago and can feel the difference.

My new self-inflateable is the yellow kway expedition series and is heaven on earth compared to that old foam matress.