This is true. Recent research shows that from way back – and across cultures – people would sleep for a few hours, then wake up, talk, pray, do chores, whatever, even visit neighbours, then have their “second sleep.” This lasted into the early twentieth century and was considered natural and normal. Then for various reasons we became convinced we needed eight hours of uninterrupted sleep. One theory is that it was a marketing strategy by mattress companies. Ironically, because of this belief, we become anxious when we awake, which only compounds the problem of getting back to sleep. Both my grandmothers slept less as they aged. When they woke in the night, they’d read, watch TV, write letters or knit, then go back to sleep when they were ready.
If you suspect you’re not fitting this “natural” pattern, and it’s impacting your health, I second undergoing a sleep study to determine underlying causes. Mindfulness exercises have been shown to be useful for muting middle-of-the-night worries. There are probably basic how-to videos on YouTube.
This is my experience. It helps me fall asleep quickly, but a few hours later, bang, I’m awake. I use it only for rejigging my system when I have jet-lag.