Script writers often go for laughs when they have their characters faint in uncomfortable situations, like the first-time dad in the delivery room.

But passing out in real life isn’t a laughing matter, despite the fact that fainting (also called syncope) is frequently brought on by something non-life-threatening. Among possible causes are dehydration, overheating, exhaustion or a strong emotional response.

A common type of fainting, especially among children and young adults, is called vasovagal syncope. In these cases, fainting stems from excessive stimulation of the vagus nerve, a regulator of blood pressure and heart rate.

The person passes out when their blood pressure drops, reducing blood circulation to the brain. Stress, pain, hunger, and use of alcohol or drugs are among the potential triggers. These types of faints become less common as we age because the nervous system doesn’t react as quickly.

Other fainting episodes can be a sign of a significant medical problem, including heart disease, anemia, low blood sugar, a seizure disorder or a disease of the autonomic nervous system.

Heart disease was the culprit for the Rev. John O’Malley, 84, a Catholic priest who was saying Mass at a River Forest church in early 2017 when he passed out. His fainting spell was triggered by chronic arrhythmia (irregular heartbeat), together with bradycardia, a slower than normal heart rate that makes it hard for the heart to pump efficiently.

The retired educator agreed with his physicians that it was time for a pacemaker implant to help regulate his heart rate and reduce the risk of fainting. Soon after the procedure, O’Malley was able to return to his normal, active schedule.

Fainting caused by a heart condition is called cardiac syncope. In addition to a heart rate or rhythm issue, the condition might be a blood clot in the lung, narrowed arteries, heart failure, a narrowing of the aortic heart valve or another problem with the structure of the heart.

When does fainting raise a red flag? According to the American Heart Association (AHA), the following factors suggest that a fainting spell might be tied to a serious disorder:

• It happens during exercise
• It’s associated with palpitations or other heart irregularities
• There’s a family history of recurrent fainting or a related sudden death

What can you do? The AHA recommends that you sit or lie down when you experience these signs that you’re about to faint: dizziness, nausea, sweaty palms and possibly, disturbed vision. If you have fainted, seek a medical evaluation. This should include a health history and measurement of your blood pressure and heart rate. An electrocardiogram is also recommended.

To find out if you’re at risk for heart disease, take an online HeartAware assessment. You can also call 630-527-2800 to schedule a heart scan or make an appointment online.