Dropping temperatures and eggnog won’t create new heart problems, but cold weather and some holiday-related behaviors can exacerbate existing conditions, and deaths from heart disease hit their peak every December and January, with spikes on Christmas Day and New Year’s Day, according to a University of California-San Diego study.

It’s unclear why winter makes heart disease deadlier, but the statistics on deaths in December and January show that cold weather can spell disaster, said Dr. Cam Patterson, chief of cardiology and University of North Carolina at Chapel Hill.

Part of the problem, Patterson said, is that many people aren’t aware they have heart disease until it becomes symptomatic - for example, when they have a heart attack. “In many cases the heart disease is a ticking time bomb and cold weather is what sets it off.”

There are several weather-related factors that affect heart heath, Patterson said. Exposure to cold weather can increase blood pressure, which stresses the heart. Blood also becomes thicker in the cold, which can increase the risk of clotting. And lower temperatures lead the blood vessels to constrict, which reduces blood flow. All three of those factors can combine to spell disaster for someone with heart disease, he said.

There are winter-related lifestyle factors at play as well, Patterson said. Heavy snowfalls like those seen in the east over the past week can someone to overexert himself beyond his capabilities - Patterson gave the classic example of the couch potato who has a heart attack while shoveling snow.

And much behavior associated with the holidays can cause problems for those with heart problems, Patterson pointed out. People tend to drink more than usual during the holidays, which can lead to something doctors refer to as “holiday heart” - a rapid, irregular heartbeat called atrial fibrillation caused when alcohol irritates the muscle of the heart’s top chamber.

Changes in diet can also have effects that stick around well past January, Patterson said. “It’s clear that has a long-term contribution towards heart health.” For adults, most of their weight gain comes during the holidays, he said - an average of a pound each year, often more for those already overweight. And that holiday weight gain tends to still be there by the same time next year.

“It’s harder and harder each year to stay healthy, from a heart perspective,” said Patterson, “when that’s going on.”

If you find yourself feeling blue once the holiday season is over, watch for the possible risks that could mean for your health, Patterson advised. “There’s a link between your mood and your heart on a number of different levels.” If depression lingers, see your doctor about your options.

There’s plenty that can be done in advance to avoid visiting an ER during the holidays, Patterson said, if you treat the holidays as a great opportunity to set higher standards for yourself. The best thing you can do during meals is to pay attention to your portion sizes, he said; one easy way to do this is to put healthy items on your plate first, leaving less room for unhealthy options. Try to focus on just a few special days for dietary splurges, he suggested, not a few weeks. “Don’t think of it as a holiday season, think of it as a holiday.”

Also, you can plan ahead for tricky situations, even if your schedule is up in the air, Patterson said. For example, if you’re going to be travelling, pack healthy items for airport waits in your carry-on luggage. Also, if you already take medication for a heart prescription, make sure you have enough to get you through the season and bring it with you if you travel - just a few missed doses can have serious health consequences.

Longer term, a regular exercise routine will help you stay heart-healthy throughout the year. And it’s always important to know your numbers, Patterson reminded: blood pressure and cholesterol. Keeping track of these health statistics can help catch heart problems early, he said. “One of the challenges with heart disease is that so many people walk around with severe heart disease that is not yet symptomatic.”

TORONTO (Reuters)