Our hearts pump blood through our bodies for the duration of our lives, through an electrical system that coordinates each and every beat. It is, truly, like a well-oiled machine.

“The heart’s system is not unlike the electrical system in a car, which times the pistons that help to spin the car’s wheels around,” says Mark Anderson, M.D., Ph.D., director of the Department of Medicine in the Johns Hopkins University School of Medicine, whose lab has recently made great strides in better understanding how heart rhythms are moderated at a cellular level.

Usually the heart’s electrical system works flawlessly, and we rarely notice it—though some people are more naturally attuned to their heart rhythms, particularly at night when other things are quiet and still. Disruptions in heart rhythms can happen, however, and when we’re aware of them it can be alarming. How can you tell if a trip of the heart requires a trip to the doctor?

Changes in Heart Rhythms Are Usually Harmless

Our heart rate adapts to our body’s need for energy throughout the day, whether it’s for walking up the stairs or a bout of strenuous exercise. These tempo changes based on physical activity are perfectly normal.

Other common situations can trigger changes in heart rhythms too. Mild dehydration can cause the heart to beat more quickly; that’s the body’s way of trying to maintain the flow of blood when there’s less available for every beat.

A change in medication, or an interaction between medications, can trigger a temporarily abnormal heartbeat—another reason to always share medication and supplement routines with your health care team. And while the resolution can be simple (such as resting, rehydrating, or changing medications), it’s sometimes beyond our ability to understand why we feel a change in our heart rhythms or if it’s the symptom of a more urgent medical situation.

When Changes in Heart Rhythms Warrant a Physician’s Attention

Though most fluctuations in heart rhythms will likely be harmless, there are times your first response should be to seek medical advice.

• Your symptoms are sudden and abnormal. “If there’s a clear first time that you notice a rhythm change in your heart, it’s a good idea to alert your doctor,” Anderson says. “You should also call your doctor when a change in heart rhythms corresponds to chest pain, losing consciousness or a prolonged sense that you might pass out.” Likewise, contact a medical professional if a rhythmic abnormality persists.
• Your history involves other heart issues. If you were born with a malformation; if you’ve had heart surgery; if you’ve had a heart attack or long-standing, untreated high blood pressure; or if there is something otherwise abnormal with your heart and you notice abnormal heart rhythms, you should see your doctor.
• Your family history puts you at increased risk. Your doctor may ask you to attend more closely to changes in your heart rhythms if your family has a history of heart disease or sudden death.