A half hour is all you need to maintain proper weight, get your blood flowing and improve health, according to the Society for Vascular Surgery, which forwarded us a list of calories burned by various winter sports from Livestrong.com.

In one hour, a 155-160 pound person can burn:

+511 calories cross country skiing

+365 calories downhill skiing

+563 calories playing ice hockey

+511 calories ice skating

+400 calories shoveling snow by hand

There hasn't been any snow here so far this winter, so how about burning :

+281 calories bicycling

+329 calories carrying golf clubs

+211 calories walking the dog

“Welcome 2012 as your year to become physically fit and keep your vascular system healthy,” said Dr. Anil Hingorani, a member of the Society for Vascular Surgery. “Winter sports burn calories, increase your heart rate, and keep your blood flowing at a healthy rate.”

Inactivity leads to 250,000 deaths a year, according to the medical journal Circulation. Those not physically fit are 4.5 times more likely to die prematurely than fit people. 

What's your winter exercise?