The only important thing is to get your heart rate elevated. The main muscle that can do that is the thighs and calves. So running or walking at incline on the treadmill (dreadmill) will do the job most efficiently. I will do a stair routine. That's starting at 10mpm for five minutes, then 9mpm, then 8, then 7 then 6. Then climb back down: 7mpm, 8mpm, etc.

Another workout is doing a flat 12mpm but every 10 minutes crank the mill up to 6mpm and hang on til you're about to puke, then slow it down. Running slow gets the body into fat-burning mode. Sprinting releases growth hormone which makes the body continue to burn fat after the workout is over.

I never do weights; I get enough exercise just shoveling snow this time of the year.