Lightweight inflatable sleep mats – normal to deflate a bit overnight?

I bought a reasonably fancy mat from one of the big manufacturers during lockdown, then barely used it for a year or three.

Having now used it a few times I was disappointed that it seems to gradually deflate overnight until come early morning my hips and/or bum are pretty much on the ground.

Obviously I did the bathtub test and found and patched two tiny holes (both of which quite difficult to find even under water) but tried again last night and still ended up on the floor in the morning!

I am reasonably heavy (90kg) and move around a fair bit during my sleep. I’d also read about mats deflating slightly as the air inside cools down, but last night I tried it on my kitchen floor which is insulated.

Anything I should know before I drive myself crazy looking for leaks which aren’t there?

Ta

My old thermarest (2009) didn’t when it was new then it started to pick up holes often so I retired it.

My new one doesn’t.

Both were neoair.

I’ve had several other brands over the years which have “deflated” over night – two of them from a UK based brand wasn’t actually deflating but delaminating- which gave the same symptoms

Ps – a misting bottle of a strong washing up liquid /water mix proved more successful than a bath for locating holes for me. I found some of them only showed up under me being on it.

Do you think your 2009 one was picking up holes due to age? My one has had a very easy life unrolled but deflated on top of a cupboard.

Pretty disappointing if it’s punctured just due to use, not sure how I could have been any more careful (always use a footprint under tent).

Bathtub is filling as we speak..

They shouldn’t deflate overnight. My NeoAir xlite has for the last 3 or 4 years, I can’t find a leak and as I wake up with just enough left to keep me off the ground and it gets so little use these days, I’ve never shelled out the inordinate amount of cash they now cost for a like for like replacement.

My NeoAir Xlite has always lost a little air since it was new. Never been a problem so I haven’t done much about it. In the morning it’s still firm enough to sleep on. Only really by the next night would it be “soft” but a quick single-breath before bed sorts that.

I’ve got a variety of mattresses, that span nearly 30 years I reckon. They all stay up all night (yes yes), the only time one hasn’t had been a tiny hole or grit in the valve.

The holes have on occasion been almost impossible to find, the tiniest leak maybe a miniscule bubble every 30 seconds. Very frustrating, my tip is use warm water in the bath, it’s nice to have on your hands and also helps keep the air pressure up

If the bulk isn’t an issue you join me in a rekindled love for the z folding foam mat

They shouldn’t deflate over the course of a night. Either you’ve a puncture or there is an issue with the valve. Even a small piece of grit can affect the latter.

If the bulk isn’t an issue you join me in a rekindled love for the z folding foam mat

Ha, yes, my renewed effort to find and fix the leak is so I can sell it (no doubt at great loss) and get a foam one. I’ll mostly be camping with a hyperactive 6 year old in the tent, no place for a lightweight £150 inflatable mat!

Mine don’t deflate unless they have a puncture.
This includes ancient Decathlon/Forclaz and new lightweight Robens x2

If a Thermarest is misbehaving, contact Cascade Designs as they have a very good warranty and are very good at honouring it.

My experience with Exped was not as good; the company themselves didn’t want to know, but Lyon Equipment, the UK importers, were excellent.

I did another bathtub test and I found another hole, which at least explains the continued deflating but begs the question how I’ve managed to puncture it three times in about 5 or 6 outings!