Did you know that cold weather, gloomy moods, binge working, big meals, and even gum disease can be heart attack risks?

Those are just a few of the startling new discoveries from the research front, prompted by a longstanding medical mystery: why people who lack traditional risk factors still suffer heart attacks.

Indeed, about 50 percent of people who are hospitalised for heart attacks have normal cholesterol levels—and many also have normal blood pressure and don’t smoke, notes John Lourié, MD, FACC, director of the Heart Attack Prevention Center in Bradenton, Florida.

Adding urgency to the quest to uncover hidden triggers is the grim fact that in many cases, the first symptom of cardiovascular disease (CVD) can be a fatal heart attack or stroke.

CVD ranks as the leading killer of Americans.

Here’s a look at some little-known heart hazards—and how to protect yourself.

Cold weather

Icy temperatures raise heart attack risk by causing blood vessels to constrict, which can trigger a sudden jump in blood pressure, reports the Cleveland Clinic.

Combined with outdoor exertion, the results can be extremely dangerous. For example, more than 11,000 Americans are hospitalized each year after shoveling snow. What’s more, a new study presented this month at the American Heart Association’s International Stroke Conference in San Diego links chilly weather, high humidity and big daily temperature shifts to increased risk for being hospitalized with stroke.

Conversely, for each 5 degree-rise in outdoor temperature, risk dropped by 3 percent. Earlier studies also reported peak rates of stroke in winter. To stay safe, dress warmly for winter activities and avoid overtaxing yourself.

Binge Working

Workaholics beware: Not only is stress a major culprit in heart disease—contributing to one-third of all cases—but chronic overwork may double the danger of heart attack, reports NBC News.

The good news, however, is that stress-reducing activities can do your heart a great deal of good, says Dr. Lourié. “One study found that when people participated in a stress management program—even if they didn’t consider themselves to be stressed—both their blood pressure and blood sugar levels improved.” One of the best prescriptions for a healthier heart is more frequent vacations, with some research suggesting that taking more time off can actually add years to your life, as well as lowering heart attack risk.

Mouthwash

Using certain mouthwashes may be a “disaster” for cardiovascular health, by magnifying risk for heart attacks and strokes, British scientists report. The study linked using a powerful disinfectant brand called Corsodyl, which contains the active ingredient chlorhexidine, to spikes in blood pressure within hours among healthy volunteers.

However, you shouldn’t take this research as an excuse to neglect your oral health, since having gum disease is linked to higher risk for heart attacks, too, reports Dr. Lourié. A 2013 study of 420 people ages 60 to 76 found that improved dental care significantly slowed progression of plaque buildup in participants’ arteries, with the study authors reporting that their research provided the strongest evidence to date that healthy gums can boost heart health.

Sugar and Simple Carbs

Not only are donuts, candy, and other sweets fattening, but they can actually be deadly, according to new study—the largest of its kind. "The risk of cardiovascular disease death increases exponentially as you increase your consumption of added sugar," the study's lead author, Quanhe Yang, a senior scientist with the Centers for Disease Control and Prevention, told USA Today.

In addition, other simple carbs—such as baked potatoes—have similar risks, Dr. Lourié reports. “These foods are quickly converted to sugar in the bloodstream, which damages blood vessels and contributes to insulin resistance, the root cause of type 2 diabetes and some heart attacks. In addition, these foods are highly inflammatory and make cholesterol more dangerous.”

Depression

Chronic depression can literally break hearts, with a number of studies suggesting that it’s an independent risk factor for CVD, even when all likely cofounding factors, such as smoking, obesity, and lack of exercise, are taken into account, says Dr. Lourié. While past studies found that treating cardiac patients for depression didn’t boost their heart health, a groundbreaking new study reports that early treatment—before signs of arterial disease set in—can cut risk for future heart attacks and strokes by nearly 50 percent.

High Levels of Myeloperoxidase (MPO)

Levels of this inflammatory marker—a component of white blood cells—are the single best predictor of heart-attack risk, a 2013 study by Cleveland Heartlab and MDVIP reported. The research was published in the peer-reviewed journal Future Cardiology. Now, an even newer study, by Cleveland Clinic, suggests that MPO may also be the villain that makes good cholesterol go rogue and clog up arteries, as I recently reported. There is a blood test to check MPO levels, widely available through medical providers. People with high levels are more than twice as likely to die from cardiovascular causes, according to Cleveland HeartLab. Ways to reduce inflammation include losing weight, exercising more, and eating more fruits and vegetables—and less sugar and fat.

Eating a Big Meal

Chowing down heavily increases risk for a heart attack within the 26-hour period after the large meal, Cleveland Clinic reports, citing the recent death of actor James Gandolfini as a tragic example. One theory is that overeating elevates levels of levels of the hormone norepinephrine, which in turn can raise blood pressure and heart rate.

Migraine headaches with aura

Women who suffer from migraines with aura (often marked by visual symptoms, such as seeing flashing lights) are at higher risk for both heart attack and blood clots, according to two studies presented at the American Academy of Neurology’s Annual Meeting last year.

The first study included 27,860 women participating in the long-term Women’s Health Study. The researchers found that migraine with aura was a stronger risk for heart attacks than smoking, high blood pressure, family history, or obesity. In fact, it was the second greatest risk, after high blood pressure. 

As I recently reported, this type of headache doubles women’s stroke risk, with new stroke guidelines for women reporting that in women with this disorder, smoking boosts stroke risk by up to 900 percent—offering yet another great reason to snuff out this deadly addiction.

The second 2013 second study found that women who experience migraine with aura are much more likely to develop blood clots, particularly if they also used birth control pills, suggesting that other forms of contraception would be the safer option.