Abnormal heartbeats, or arrhythmias, are common conditions that span an array of types and severities — many are harmless, in fact. Normal heart rates range from 60 to 100 beats per minute, are evenly spaced, and usually go unnoticed. Rhythm problems, which can feel like fluttering, racing, or slow beats and can cause dizziness or chest pain, develop when the electrical conduction or muscular action in a part of the heart is interrupted. For example, in AV blocks, the different heart chambers don’t communicate evenly, and this sometimes feels like skipped heartbeats.
People with a history of coronary artery disease, heart attack, or even hypertension are more likely to have rhythm problems in general; other conditions that can change heart patterns include thyroid disease, anemia, or diabetes. With these pre-existing conditions, arrhythmias such as ventricular or sustained atrial fibrillation can lead to serious problems like stroke. A few surprising triggers can increase the risk of rhythm problems even in seemingly healthy people, though.
Besides caffeine, which is the most common arrhythmia-causing substance according to the Heart Rhythm Society, a vagal reaction to meals can change the heart’s activity. Digestive shocks from extremely cold or spicy food — or even a very large meal that distends the stomach — add extra pressure on blood vessels and reduce the effectiveness of the heart’s pumping and electrical conduction actions. The result of this type of cardiac stress ranges from angina and heart attacks to cardiac arrest and sudden death, as seen in the death of James Gandolfini in 2013 after a heavy meal.
In addition, too much or too little of vital minerals can disrupt natural heart rates; notably, very high or very low potassium levels can trigger arrhythmias and death if untreated, because potassium is essential to conducting electrical signals in the heart. Food-related causes of abnormal heartbeats can develop because of low sugar, fluid, or vitamin levels, too. Learn more about how foods affect your heart rate so that you can avoid symptoms of arrhythmia.
Like caffeine, many common medicines affect the body’s adrenergic system to increase the heart rate and impair the heart’s seamless electrical activity. Examples available without a prescription are nicotine, pseudoephedrine and phenylephrine in pills or nasal sprays, and ephedra-containing weight loss supplements, which all can cause erratic heart rates. Atrial fibrillation from medicines can develop in people whose hearts are already stressed from obesity, heart disease, or another arrhythmia risks and, rarely, in people without heart problems. The drug quantity is important, too: very high doses of steroids used by athletes, for example, can change potassium activity in cells and disrupt electrical pathways in the heart.
Problems occur less often with prescription medications. One example of a drug class historically associated with arrhythmias is macrolide (“mycin”) antibiotics; ventricular arrhythmias and sudden cardiac death might occur more often with these drugs because of changes to the QT interval, which represents electrical conduction across ventricular muscles. However, a 2016 study in older adults showed no increased risks with macrolide treatment, so the true association remains unclear. If you are prescribed a macrolide antibiotic, talk about your concerns with your doctor.
Perhaps the most unusual trigger of heart arrhythmias is meteorological. Our body temperature is integrally connected to cardiac activity. As a result, cardiac exertion is naturally higher in extreme hot or cold temperatures.
In hot weather, fluid loss from increased sweating and poor hydration can dangerously lower blood pressure and increase oxygen needs, especially in patients with existing heart conditions or in the very young and very old. Chest pain, atrial flutter, or dizziness can develop quickly. Counter heat risks by increasing fluid intake, avoiding alcohol, caffeine, or added exertion, like endurance exercises.
Arrhythmia risks are even greater in cold weather. Research has documented increased rates of atrial fibrillation, heart attack, and stroke in populations across the globe during autumn and winter months.
Three possible reasons are behind the greater risk:
- Increased clotting factors that inhibit normal blood flow. However, this mechanism is still poorly explored and hypothetical.
- Hypothermia, defined as a body temperature lower than 95 degrees F, when the body cannot form the energy to maintain its functions. Hypothermia can develop suddenly and silently in all ages, especially in windy conditions and dampness. The low body temperature causes the heart rate to decrease, increases stroke risks from blood vessel constriction, and can lead to death in the most susceptible patients.
- Increased exertion from seasonal activities. Extra stress on the heart is a common development during snow shoveling in the winter. In some cases, though, even walking through snowdrifts or flurries is enough stress on the blood vessels and heart to cause rhythm changes when parts of the heart muscle stop working in sync.
Are you at risk?
Remember that most rhythm problems are temporary and not serious. Knowing how to track your own pulse and how to avoid cardiac stressors are good ways to prevent serious arrhythmias.
Nicole Van Hoey is a freelance writer and editor for consumer and professional health publications. She underwent open heart surgery in August 2016 and writes about the experience, including cardiac rehab, for HealthCentral. She can be found on Twitter @VHMedComm and writing about family life after heart surgery at Bloglovin’.