If you're out shoveling snow this winter, research from Harvard's School of Public Health has uncovered something that should serve as a warning.

Tracking incidences of cardiovascular-related hospital admissions associated with a major snowfall, the Harvard researchers found that not the same day or even the day after, but two days after a snowfall, hospital admissions for heart issues jumped by 23 percent.

That means if you've been out clearing the driveway or sidewalk, for several days after shoveling don't dismiss pain around your shoulder blades, arm, chest, jaw, left arm or upper abdomen as simple muscle soreness.

And follow these safety tips to avoid falling victim:

• Cold air makes the heart work harder; do a short warm-up inside by stretching and jumping. It'll get muscles and heart ready for the exercise.

• When shoveling deep snow, take it off by layers.

• To help the snow move off the shovel more easily, spray the metal scoop with - we're not kidding - nonstick cooking spray!

• Remember to lift with your legs; keep your back straight.

• If you start to feel pain or discomfort in your shoulders, neck or chest, stop immediately.

• And remember, alcohol doesn't really warm up your body. Mixing shoveling and alcohol makes you more likely to slip, fall and wrench your back.