You might assume that the length of your commute is the main thing that affects how pleasant or nightmarish it is. But a number of studies show that the mode of transportation you take is also really important — both in terms of how happy (or unhappy) you are with your commute, and your overall chance of obesity.
It depends on how far you have to commute. I don’t think a 3-4 hour bike commute will cheer anyone up. Like others I’ve spoken with, activity helps wake me up. But don’t forget that studies show how inhaling exhaust fumes changes the expression of our genes.
I commute by bike to work. It takes me as long to do by bike as it does to commute by car – that’s in the morning, when there’s no traffic. In the evening, I pass lots of cars stuck in traffic. A co-worker who lives in the area told me that the commute by car took them over an hour one day.