I mostly wear sleep pants and/or gym shorts in the morning when I leave the bed. The warmth of the bed wears off pretty fast in my house, so staying nude is not always easy most months of the year.I have found that on nights when I can't fall asleep, if I pull on a pair of sleep pants or sweat pants, that I will doze off quite easily. I don't know exactly why that is, but it works. I don't think I have restless leg syndrome, but for some reason, having my legs covered makes my body relax. Most nights, though, I sleep with nothing on.
I read a synopsis of some research that sleeping with socks can improve sleep when insomnia is a problem. Has to do with warmth in extremities . That may explain your reaction to the sleep pants. I much prefer sleeping nude too but when I dont feel well sometimes the socks stay on.