Not just a cot, but put a pad underneath it...we also put out heavy clothes under the pad...I also wear a beanie hat to cover up my mellon...
but in all seriousness, unless someone stokes the fire all night, it is going to get cool...I pack with horses, and I always go in with atleast two sleeping bags...(keep in mind I am in Montana) and one is good to -20 and the other is the alaska guie model big rectangular one good to -40...it is always easier to open it up and cool down than warm up from freezing...
there have been some nights where my feet froze, so, I started wearing socks to bed even in the early fall hunts...it cuts down on sweat, and it keeps them warm in cold nights...
but my time sleeping in wall tents is coming to an end...got a nice camper, and can ride from the camper on horses...much more cozy!!!