|Photo by Vidibio. Licensed under Creative Commons.|
First, if you and your partner sleep naked, you have a slightly --or perhaps considerably-- greater prospect for sex. Sex is often a great soporific. Or, let's put it this way, sex is better at relaxing you than editing that office report in bed. According to Sheenie Ambardar, MD “After orgasm, the hormone prolactin is released, which is responsible for the feelings of relaxation and sleepiness"
Second, sleeping naked reduces the feeling of weight on your body. Pajamas, nightgowns and other bed clothes can twist and that can cause mini-wakings. You know how that works: You turn one way, but your pajama pants turn the other way. The less pressure, even from something as relatively light as a flannel nightgown, the more at ease your muscles will be. The less often you'll wake up at night.
Cooler temperatures are better for sleep: Between 60 and 67 degrees is optimal. Having a blanket on top of you makes you warmer, but it's easy to slip your leg out from under that blanket, or to pull it down or entirely off of you, if you become too hot. But it's harder to achieve the best sleeping temperature if you're wearing pajamas and you have a blanket on top. Lose the pajamas for a cooler environment and a better sleep.
Some people report that when they sleep naked, they wake up more refreshed because they've sweat less during their sleep. Waking up more easily, more refreshed, is a sure sign that you're sleeping better. Waking up refreshed is sleep's mission.
Not sweating also reduces the need for a nighttime glass of water: Sweat, drink. Drink, have to go to the bathroom. Sleeping naked can help break this thirst, drink, bathroom cycle.
Give this experiment a week, or a month if you can. As with many sleep tips, there's no way to know if it's going to work for you or not. The only reason not to sleep naked is that doesn't help you sleep faster or longer. But the only way to know is to try.