If you're traveling to a frozen tundra like I am and looking to get the blood flowing, I highly recommend the 7-minute workout. It's a misnomer because after rest one full cycle actually takes 8 minutes, and you really ought to do it 3 times in succession, making it a 24-minute workout. At any rate, it's good and burns plenty of calories. http://well.blogs.nytimes.com/2013/05/09/the-scientific-7-minute-workout/?_r=0