I agree that causality is not documented, but that is not always possible. If you look into the average car driver in my local area, many of them are obese. However, if you take the train, obese people are extremely rare. Also, living closer to a train station definitely raises the price of a house significantly, here, and also seems to lower the BMI (my conclusion, based on observing).
As you indicate, there can be a social mechanism that explains this, but that is where studies like this try to make better statistics than what we do by just observing people.
Causality is difficult, but the latest Danish official health advice is to walk 30 minutes per day. Walking to/from train station is perfectly adequate, and while you're in the train, there is free internet, and in intercity trains, you have 230V power and tables. In other words, if you need 30 minutes of walking and need to work 8 hours per day, the extra time spent on a train, compared with working at home, is almost none, whereas if you need to go by car, all the transport time is pure waste. That is one of the reasons why I try to use the train as much as possible, I simply don't have the time for driving a car. |
