Why do sudden muscle jerks occur during sleep?

Sudden muscle jerks during sleep, commonly referred to as "sleep starts" or "nocturnal myoclonus," may generally be attributed to the following factors:

1. Physiological factors: such as excessive fatigue, high levels of mental stress, or vigorous exercise before bedtime. These factors may cause muscle tension or nerve excitement, thus triggering jerks during sleep.

2. Hypocalcemia: Calcium ions play an important role in nerve conduction. When calcium levels are low, nerve cells become more excitable, increasing the likelihood of muscle jerks. This is commonly seen in adolescents during growth spurts, pregnant women, and middle-aged or elderly individuals.

3. Epileptic seizures: Symptoms of epilepsy include convulsions, which may be accompanied by impaired consciousness and frothing at the mouth. Epileptic seizures are more likely to occur during sleep, and timely medical attention is required.

4. Restless legs syndrome: This primarily manifests as uncomfortable sensations in the lower limbs, such as crawling or creeping feelings, prompting patients to move their limbs involuntarily. It may also present as muscle jerks during sleep.

5. Other factors: such as cold stimulation, prolonged local pressure, trauma, brain disorders, and medication effects may also lead to muscle jerks during sleep.

If jerking episodes occur frequently or are accompanied by other symptoms, prompt medical consultation is recommended.