Es una forma de decir "tiempo para mí". Compáralo con "lunch time", "tiempo de almorzar", or "departure time", "hora de partir". Por lo tanto tu frase se traduce como: La gente feliz además dedica más tiempo de su vida para sí mismos. Espero que eso te ayude.

It means that happy people create time for themselves. Time where they don't have to worry about anything but themselves. For me that means reading a book or taking a bath. What do you do during your "me-time?"

Hi Lorena "Me time" is time that you devote to yourself, time spent doing things that you WANT to do, not doing the things that you HAVE to do. Making yourself a priority above life's mundane tasks I hope I have explained this ok