With the year's first major snowfall, Northwestern Medicine cardiovascular experts are warning people to take to take it easy while shoveling. Those with known heart disease should be especially careful.

Clinical chief of cardiology at Northwestern Memorial Hospital Charles Davidson says "shoveling show is very strenuous physical activity that puts a high degree of stress on the heart and its circulation."

Davidson says that in people at risk of heart disease, shoveling snow "may be putting them at risk for very serious heart problems including heart attacks."

Safety tips from experts include starting early, because shoveling snow is easier when it first falls, before it becomes compacted and heavy.

Warm clothes can also help maintain body temperature and circulation. Other advice includes staying hydrated, warming up and taking frequent breaks.