I have been at times. I was a competitive rower for 5 years until I took a break last year. I'm getting back into it but it's hard. I find exercising in the summer really easy, I can go running, biking, rowing, etc. but I hate stationary exercise and I get depressed in the winter so I find winter training difficult to keep up with.
When I was still rowing, however, I would be up at 4am every weekday, 5am on Saturdays, and would bike to rowing, 15mins, row for 1.5-2hrs, then bike to work, 7.5km that would take me ~15mins with traffic lights and a killer hill at the end, usually averaging 36-40km/hr through the city. I would then work a somewhat physical job as a groundskeeper, followed by a 1-1.5hr evening rowing practice. Needless to say I couldn't eat enough but I was in amazing shape.
I'm currently swimming twice a week, practices are monday, wednesday and friday but I've got class during the wednesday practice so I'm only going to start that this week. I will also throw in some rowing on tuesdays and thursday mornings and weights those afternoons.