I just heard about this the other day from a doctor. Also, old literature refers to the first and second sleeps of the night. Modern working hours when the agricultural era ended forced people to cram in sleep in one session.
The best DIY projects & DIY ideas and tutorials: sewing, paper craft, DIY. Ideas About DIY Life Hacks & Crafts 2017 / 2018 DIY Life Hacks & Crafts : To stop nighttime coughing in a child (or adult as we found out personally) put -