Your heart may be in danger during the winter months, and it's not just because you're shoveling heavy snow. Even if you pay your neighbor's teen to clear out your driveway, you may still imperil your heart just by walking outside.

As just one function of many in your body's attempt to keep you warm, your heart will actually beat faster in cold weather. This is done in an effort to pump blood around your system to protect major organs. But in one of the very few design flaws found in your anatomy, cold weather also causes your arteries to constrict. Consequently, your blood pressure rises and your pulse increases, both of which can lead to blood clots. Blood clots can occur suddenly, blocking arteries to the heart, starving it of oxygen and causing permanent damage to that vital muscle. Making matters worse, hormone changes that occur during cold weather can make blood more likely to clot.

A heart attack happens when a blood clot suddenly and completely blocks one of the heart arteries, starving part of the heart muscle of oxygen. This usually causes permanent damage to the heart.

When not enough blood flows to the heart because of a spasm or arterial obstruction, the result is angina. Symptoms are usually felt as a heaviness or feeling of pressure across the middle of the chest with pain sometimes radiating down one or both arms and up into the neck or jaw. Angina is most commonly experienced during the cold months (and/or when you are stressed).

Of course, sometimes your body's efforts to keep you warm fail, and the endgame there may be hypothermia, defined as when your body temperature drops below 95 degrees Fahrenheit. The youngest and oldest among us are most at risk because they have lower levels of subcutaneous fat and may not be as aware of temperature level changes. When hypothermia hits, your heart, nervous system, and other organs begin to fail. Untreated, hypothermia can lead to heart failure and death.

Be on the lookout for these hypothermia symptoms:

• A lot of shivering or a halt in shivering
• Lack of coordination
• Slurred speech
• Confusion
• Weak pulse
• Slow, shallow breathing
• Drowsiness

Be sure to track wind and precipitation conditions during the winter months as well as the temperature. Snow, rain and high winds can remove the layer of heated air which surrounds your body, and being wet or damp causes the body to lose heat faster than it would at the same temperature in dry conditions.

Sources: UPMC HealthBeat