Muscle twitches, especially involving the eyelids, calf or thumb -- are fairly common.
Rarely, they can be a sign of a nervous system disorder, the U.S. National Library of Medicine says. Signals of a serious muscle problem include a change in muscle sensation, size, and a feeling of muscle weakness.
On the other hand, most muscle twitches aren't anything to worry about and only last for a few days or less. The NLM offers this list of common causes:
Having a dietary deficiency.
Getting too much caffeine.
Taking certain medications, such as steroids, estrogen hormones or diuretics.
Having anxiety or stress.
Health Tip: Bones, Muscles and Aging
Getting older means changes throughout your body, and the bones and muscles are no exception. So get them into shape, and help ward off certain effects of aging.
The American Academy of Orthopaedic Surgeons offers this advice:
Do lots of stretches. Stretching will help your muscles stay flexible.
Try some lightweight training to build up and strengthen your muscles.
Over time, getting regular exercise can help you retain muscle mass and help prevent weight gain.
Even occasional exercise can benefit blood pressure, heart health, and some studies indicate it might reduce your risk of cancer.
Getting just 30 minutes of exercise can boost your overall health. Try fun activities such as dancing and swimming.
If you haven't exercised before, talk to your doctor before you start.