There are some tricks, so to speak. I purposefully will only live a 30 minute walk to work. While I realize not everyone can do this, I make it such a high priority that I do sacrifice a lot to ensure it happens. I also try to ensure a gym is between work and home. This way on average I walk an hour a day to and from work, and the fixed cost of adding a 30 minute workout is essentially zero. So 1.5 hours a day is spent combined physical activity and commuting. It makes exercise very cheap.