Family Health What Causes Charley Horses? By UPMC, September 22, 2016 Charley horses, painful muscle spasms usually in the leg or foot, can happen to people of all ages and lifestyles. Worse yet, they can strike at any time of the day or night, though it’s common to have muscle cramps while sleeping. Find a UPMC primary care physician by visiting the UPMC Primary Care website or by calling 1-855-676-UPMCPCP. Although they appear to happen randomly, some habits and conditions have been linked to charley horses, and there are steps you can take to prevent them. What Is a Charley Horse? A charley horse is another name for a muscle spasm, which is when a muscle contracts and will not relax. Muscle spasms can happen to any muscle in the body, but they are most common in the leg and foot. During a muscle spasm, the muscle becomes hard and tight and may be tender to the touch. After the spasm subsides, the muscle may be sore for hours or even days. Charley Horse Causes While there is no definite cause for charley horses, several factors make their occurrence more likely, including: Dehydration Exercising in very hot or cold temperatures Overusing the muscle Stress Poor blood flow/circulation Not getting enough vitamins/minerals Standing or sitting too long without moving Malfunctioning nerves Certain medications How to Treat Charley Horses Most of the time, muscle spasms resolve on their own. To help ease the pain when they happen, you can try one of the following: Apply heat during the cramp and ice after it ends Gently stretch the muscle Massage the muscle The best treatment for charley horses is prevention. You can take steps to prevent them by: Drinking plenty of water Stretching before and after exercise Eating foods high in magnesium, potassium, and calcium Wearing comfortable, supportive shoes In some cases, repeated charley horses can be the result of nerve issues, which can be diagnosed with an MRI scan. If you experience muscle spasms frequently, they may be a symptom of an underlying health condition, and you should consult your doctor.