As winter sets in, bringing ice and snow to many parts, this is an opportune time to remind people how cold weather can affect the heart, especially if you have cardiovascular disease, say the American Heart Association (AHA).

If you are outdoors in cold weather, you should avoid sudden exertion, like lifting a heavy shovel full of snow, say the AHA, who warn that even walking through snow, especially heavy snow and snow drifts, can strain the heart.

Also, if you exert yourself over a long period, such as doing winter sports and don’t take certain precautions, you are risking accidental hypothermia, a potentially fatal condition where the body’s temperature falls below 95 degrees Fahrenheit (35 deg C), because it can’t make enough energy to keep the core warm.

Hypothermia slows down the body’s circulatory, respiratory, and nervous systems, and if it becomes severe, it causes irregular heartbeat, which can lead to heart failure and death. It claims more than 700 lives in the US every year.

Hypothermia often happens gradually, although it can also occur in minutes, for example if a person falls through the ice into cold water.

The symptoms of hypothermia are:

  • Skin that is cold to the touch.
  • Shivering at first, then it stops.
  • Feeling drowsy, lethargic.
  • Weakness, clumsiness, slow reflexes, lack of coordination.
  • Feeling irritable, being more aggressive, combative.
  • Confusion, delirium, hallucinations.
  • Seizure, stupor, coma.
  • Breathing slows down, becomes shallow or arrested.
  • Heartbeat slows, becomes irregular, or arrested.

People with heart disease, as well as children and the elderly are most at risk.

A person with coronary heart disease will often suffer chest pain or discomfort from angina pectoris when out in cold weather. There is also evidence to suggest that very cold winter weather increases the risk of heart attack from overexertion.

As we age, our bodies find it harder to maintain a normal core temperature, and we also become less sensitive to cold: this “double whammy” is what puts the elderly especially at risk for hypothermia, without realizing it.

It’s not just low temperatures you need to look out for: high winds, snow and rain can also take away body heat.

Wind whips away the layer of heated air that surrounds the body (the wind chill factor). If you are in a 30 mile an hour wind at 30 degrees Fahrenheit (-1.1 deg C), the wind chill effect is equivalent to being at 15 degrees Fahrenheit (-9.4 deg C).

If you are damp, say from sweating or because you are soaked from rain, then your body loses heat faster than it would if it was dry at the same temperature.

The AHA suggests the best way to stay warm is to wear layers of clothes rather than relying on one thick garment, because layers trap air in between, forming protective insulation.

You can lose a lot of heat through your head, so wear a hat: one that pulls down over your ears, or a scarf or ear muffs that keep your ears warm will also protect you from frostbite on the ear. Use thick gloves and socks (or again layers, like a thin pair underneath and a thick pair on top) to keep your hands and feet warm, as they can also lose heat quickly.

Drinking alcohol before going outside or while outside is not advisable either. While alcohol gives the feeling of warmth, because blood vessels in the skin expand, the result is that heat is drawn away from vital organs, just at the time when they need to keep warm.

The AHA suggest you also consider these additional Winter Weather Tips before you reach for that snow shovel and start exerting yourself in the cold:

  • Don’t overstress your heart: take frequent breaks and pay attention to how your body feels in the breaks.

  • Don’t eat a heavy meal just before or just after shoveling: it can put too large a load on your heart.

  • The same goes for alcohol: avoid it before or just after shoveling.

  • Use a small shovel, it is safer to lift smaller amounts more times than big shovelfuls: lifting a big shovel full of snow can suddenly raise blood pressure too high as you strain to lift the weight.

  • Where possible, just push the snow.

  • If you have a medical condition, see a doctor before you start snow shovelling.

  • Learn about the signs of heart attack and listen to your body: if you are not sure if your symptoms are a heart attack, get them checked out anyway.

And finally, where the heart is concerned, minutes can make the difference between life and death: so don’t wait more than 5 minutes to call 911.

Sources: AHA, University of Maryland Medical Center.

Written by: Catharine Paddock, PhD