I don’t get the bit about public transport. Do you mean it’s unhealthy because public transport is stressful?
If we're talking about the extremely elderly, it seems better for them to be taking public transport than driving.
Which doesn't track. Public transport in Japan is peaceful. I feel more relaxed on a Train in Japan than a car or Train in Canada.
Surely the exercise that comes with using public transport outweighs that. I feel like being able to zone out and not having to focus on driving, is more relaxing to me.