As Noy says, exercise and fitness have to become a lifestyle. For myself, it is everpresent, my days and vacations are planned around it. Running, cycling, backcountry skiing, backpacking...
People who are disciplined can force themselves to do things for years at a time but they don't enjoy them and they will often take any excuse not to do exercise etc.
If you dedicate yourself 2-3 times a week to an activity you enjoy, you will inevitably want more and get the positive reinforcement. Eventually, you wont have to force it. One of my best friend's is a great athlete. He hates the T word (Training). Despite this, his life is essentially a training camp. But to him it isn't "training" because he makes it fun and it is what he loves. When he starts making his workouts with goals and such, he loses it...
I am now at the point where it is an absolute requirement in my life. I make time for it no matter what my responsibilities are: ICU call, early or late days. I will run in the dark, run from men with guns in third world countries (not really), and run around my neighborhood when I am on home call.
I love being fit, able to do almost anything "off the couch." Every activity is so much more fun when you are in shape and not suffering (unless you want to!)
It is very hard to be motivated in residency, especially in the ICU. Tricks I have used: run or bike to work. No matter how tired you are you HAVE to exercise. After that first mile, even postcall, the body wakes up and I will run 5-30 miles without sleep sometimes.
If you exercise from home, do not sit down or relax at all before you start, you will end up slackin on the couch ( I do anyway!).
Watch TV, movies or motivating documentarys while on the treadmill or bike.
Talk on the phone with friends if they dont mind the heavy breathing.
Exercise makes you sleep well, happy, lets you eat and drink tons of calories even as your metabolism slows AND you won't become a vasculopath!!!!
Just got done with call, kidney tx, aortobifem, 7 fast outpt ortho cases.
I WANT to train really bad. I am in the mood for a looooong ride. Unfortunately, I am having an outpt procedure. Damn
My wife does P90X, that thing will break you.
I suggest you start out easy with a long term plan. FInd an activity you like and commit to doing it a few times a week. Join a basketball league or ultimate frisbee or something. I like hockey. THen commit to the gym every postcall day off. The next thing you know, you are wanting more. THe workouts are not enough so you start going more often. Now you are in a routine. When ICU breaks you, take a day off. It's not the end of the world. Watch what you eat. Shrink your portions. This is the most difficult.
Or you could start running 100 miles a week like Dre'.
My residency workout routine was the gym about twice a week when I was doing good. Run 5 miles (I know, I'm a wimp Dre') 1-2 times a week. On the weekends I was busy like crazy. Long bike rides or all day snowboarding. I typically added a mountainbike ride or two in every week. Usually, if I got home early I'd head to the trails but for those months (ICU or trauma) I'd be lucky to get any workout in.
It's not so much about finding a routine for me as it is a lifestyle. Corny I know but I feel much better when I am active. I find that when I try to stick to a rigid routine I doomed to fail. But when I enjoy the activity I just want more.