I do not agree or disagree on whether or not it is. It really depends on the lifestyle and circumstances regarding an individuals' need for a nap. For instance a new mother, may need that nap during the day, because of being woke throughtout the night by her new baby. If one has surgery, and their body needs to heal, they may require that extra sleep during the day.
I know that as a human we are required a certain amount of sleep each night. We as adults may have already set a pattern for our sleep cycle. Some may require more while others less. Whether or not one works at night, or during the day, we need a certain amount of sleep.
I do beleive