February 19, 2025- Fainting or blacking out, also known as syncope, is a temporary loss of consciousness due to insufficient blood flow to the brain. There are different types of syncope, such as vasovagal syncope, the most benign kind of fainting, simple fainting without a serious underlying cause, which is common. The syncope that most concerns healthcare professionals is cardiac syncope, blacking out due to an underlying heart disease such as a heart rhythm abnormality, or arrhythmia, according to Mayo Clinic.
Others for whom a blackout can be a warning sign of a serious heart problem include people with a family history of inherited heart problems, unexplained deaths or premature sudden deaths; people whose fainting is related to exercise; and people whose fainting is associated with heart palpitations or the heart feeling like it’s racing away, according to Mayo Clinic.