In an older thread it is pointed out that, in cold weather, the air circulating under sleeping cots can be a problem. Anyone here have luck topping a cot with a mylar or "space" blanket, and then putting your sleeping bag on top of that? The idea is reflecting body heat back up. I'm curious whether this is a viable solution. Ground pads are too much for my aging self and my preference for side-sleeping. Thanks!

Sleeping on a cot is fine, summer time the air flow is good. cold weather, put a foam pad on the cot, there's your insulation. Sleep bag on the pad.  Bob's yer uncle. 

Pads are more than padding, they're also insulation. Also, the bottom of the sleeping bag doesn't provide any insulation when you smash it flat. IF it's cold out you need a pad with insulation. So, whatever pad you'd use on the ground, put it on put on your cot and you'll be warm.

I'm more inclined to using closed cell foam pads like the thermarest ridgerest with a silver side and green side.  It encompasses both of your needs.  The only problem is they are being phased out for more inflatable types, that I'm not in favor of.  The inflatable do pack up smaller, but are subject to low temp deflation and condensation inside when inflated.  Skip the mylar and go with a reflective pad.

57 minutes ago, Double Eagle said:

I'm more inclined to using closed cell foam pads like the thermarest ridgerest with a silver side and green side.  It encompasses both of your needs.  The only problem is they are being phased out for more inflatable types, that I'm not in favor of.  The inflatable do pack up smaller, but are subject to low temp deflation and condensation inside when inflated.  Skip the mylar and go with a reflective pad.

Yep, closed cell works best for me as well, even on cots. I had not heard they are being phased out, but I typically use a cheap Walmart pad. Exercise pads would work too. Actually I have 2 pads, one for car camping and one for backpacking. The backpacking pad is cut down to 2/3s the normal length to save weight and space. My coat is use as a pad for the other 3rd (legs) on backpacking trips. 

Barry

Thanks, all! A Scout is Helpful, and you certainly were.