Anxiety and Muscle Spasms

Causes of Spasms
Spasms are involuntary muscle movements, sometimes referred to as “twitches.” Cramps are also a type of muscle spasm, but generally when people talk about spasms with anxiety, they’re talking about something that makes their body twitch uncontrollably.

Spasms can affect any part of the body, including:

Hands
Fingers
Arms
Legs
Back
Elbows
Shoulders

Many people have experienced spasms at night after a considerable amount of walking, exercise, or when they’re about to pass into deeper phases of sleep. These types of spasms are unrelated to anxiety, but those with anxiety are more prone to believing that their spasms are problematic. It’s important to keep that in mind that some spasms occur naturally with no cause at all, or because of dehydration or exercise. Not all natural spasms relate to anxiety, but many people with anxiety think that their spasms are anxiety or health related.
The exact mechanism that causes spasms is not entirely known. Possible causes of anxiety spasms include:

Adrenaline: Adrenaline excites the nerves, and is released in large amounts when you experience stress and anxiety.  It’s likely that adrenaline is activating the muscles which, in turn, causes the muscles to spasm.

Nerve Excitation: Similarly, anxiety involves stimulation of neurons, or nerve cells. What that stimulation may be is not entirely clear, especially since twitching may occur when the person does not experience any anxiety, but it’s possible that the nerves or brain experience changes in nutrition, hydration, or chemical rate in a way that causes them to react.
Muscle Stress or Tension Anxiety also puts a great deal of stress on the muscles themselves. It’s one of the reasons that muscle pain is a common anxiety symptom. Since overexertion of muscles can lead to twitching, it’s possible that this may cause a muscle to twitch uncontrollably.

Even though the causes of this type of twitching are not entirely understood, and even though it can affect any part of the body (often the fingers and arms are the most effected, but even eyelids have been known to twitch), anxiety causing these issues is entirely normal.