The repetitive, low-stress, and "no brainer" act of color lends itself to relaxation. The calming effects not only helps to reduce stress levels, but also can help to bring you back to your youth. The awesome part is that anyone can do it will no skill set required! Grab a crayon and you are good to go. You can make it even more enjoyable and have your kids or grandkids color with you. Depending on the age of the young ones they may be interested in the adult coloring books, others still wanting to color a cow, astronaut, or pretty flower arrangement.
Well, apparently they were back then and still are today for people of all ages. People are making the adult coloring books bestsellers on Amazon! At the time of this writing, eight of the top twenty books on the bestsellers list, are coloring books for adults. There must be something behind this recent growth in interest.