Sanatana Dharma: a way of life or a religion?

I have read many sources that agree with one or the other, so what do you believe? Is Sanatana Dharma (hinduism) a way of life or a religion? If it is a way of life, should someone who practices the dharma partake in the activities that surround Indian culture? If it is a religion, what practices are considered religious and which are cultural? 

Say, for example, someone (who is not a native to India nor grew up with Sanatana Dharma) comes to embrace Sanatana Dharma. Say they wish to express their faith/way of life, on special occasions and in the everyday. Should they separate the religion from the culture? Or is it even possible to separate either because it is a way of life?