Tonic-clonic seizures, formerly known as grand mal seizures, comprise two stages: a tonic phase and a clonic phase. These intense seizures can be frightening to experience or observe, as extreme muscle spasms may temporarily arrest breathing.

Do you breathe when seizing?

During a tonic-clonic or grand mal seizure (think convulsive seizure), it may look like the person has stopped breathing. This is because the chest muscles tighten during the tonic or “stiffening” part of seizure. The person will usually start breathing on his or her own after the seizure.

How do seizures affect breathing?

The autonomic nervous system regulates body functions like breathing. Seizures can disrupt this system, causing breathing to temporarily stop. Interruptions in breathing during seizures can lead to abnormally low oxygen levels, and may contribute to sudden unexpected death in epilepsy (SUDEP).