A definition from Wikipedia states that:
“The term lifestyle was originally coined by Austrian psychologist Alfred Adler in 1929. The current broader sense of the word dates from 1961.
In sociology, a lifestyle is the way a person lives. A lifestyle is a characteristic bundle of behaviors that makes sense to both others and oneself in a given time and place, including social relations, consumption, entertainment, and dress. The behaviors and practices within lifestyles are a mixture of habits, conventional ways of doing things, and reasoned actions. A lifestyle typically also reflects an individual’s attitudes, values or worldview. Therefore, a lifestyle is a means of forging a sense of self and to create cultural symbols that resonate with personal identity. Not all aspects of a lifestyle are entirely voluntaristic. Surrounding social and technical systems can constrain the lifestyle choices available to the individual and the symbols she/he is able to project to others and the self.
The lines between personal identity and the everyday doings that signal a particular lifestyle become blurred in modern society. For example, “green lifestyle” means holding beliefs and engaging in activities that consume fewer resources and produce less harmful waste (i.e. a smaller carbon footprint), and deriving a sense of self from holding these beliefs and engaging in these activities. Some commentators argue that, in Modernity, the cornerstone of lifestyle construction is consumption behavior, which offers the possibility to create and further individualize the self with different products or services that signal different ways of life.”
So lifestyle is not only a bundle of behaviours, but also a reflection of our belief systems, i.e., our concept about who we are, what is our relationship with our society and with our environment (nature), etc. It’s our belief systems which shape our behaviour. Lifestyle influences every aspect of our life, includeing our health, our well-being, our social relationship etc.