Why do my muscles twitch?

Muscle twitches are extremely common, and most people experience them several times throughout their lives. While they can be annoying, it’s very rare for muscle twitches to be the initial sign of a serious illness.

Read on for answers to some common questions about muscle twitching.

What is muscle twitching?

Muscle twitches, or fasciculations, are involuntary contractions of a part of a muscle.

What muscles most commonly twitch?

Any muscle can twitch, but muscle twitches are more common in the calf muscles. The muscles around the eye is another area that’s commonly affected.

What is happening in the brain/nervous system when muscles twitch?

Muscles are divided into different parts called motor units. You can think of these units as different members of a team that makes up the muscle. When a muscle contracts gently, only a few members of the team activate. When a muscle contracts strongly, many team members activate.

Each of these motor units has a separate nerve that controls its activation. Muscle twitches occur when the nerve that controls a motor unit involuntarily activates.

What causes muscle twitching?

In most cases, we don’t fully understand why a muscle twitches. Things that are known to trigger muscle twitches include:

• caffeine
• poor sleep
• electrolyte abnormalities
• some medications

Less commonly, muscle twitches can be evidence of an underlying disease.

What are ways to stop muscle twitching?

Most of the time muscle twitches will resolve on their own. Some things that can help reduce muscle twitching include making sure you’re getting enough sleep and cutting down on caffeine. If muscle twitches are persistent, checking for electrolyte abnormalities is a reasonable next step.

When is muscle twitching a sign of a more serious condition?

When muscle twitches are part of a more serious condition, there are several other symptoms present. These include weakness and atrophy (shrinking) of muscles, sensation changes, pain and cramps.

Are muscle twitches the same as muscle cramps?

Muscle twitches differ from muscle cramps in several ways, though they’re both involuntary activations of muscles.

Muscle twitches

Muscle twitches are typically painless and involve only one motor unit, as mentioned above, so there’s little movement of an affected muscle or limb. Muscle twitches also typically aren’t triggered by certain movements.

Cramps

Cramps are painful, forceful, involuntary contractions of muscles. The calves and hamstrings are commonly involved, though any muscle can cramp. Cramps often occur at night and can be triggered by stretching or activating a muscle, especially if it’s not one you have been using regularly (such as when starting a new exercise program).

When should I see a health care provider about muscle twitching?

It’s reasonable to discuss muscle twitches with your health care provider if they’re becoming bothersome enough to interfere with daily life or sleep, or if you’re experiencing weakness, atrophy or cramps.