I will never forget my first encounter with a charley horse. It was in the middle of the night and I was literally woken up by a calf muscle that went from 0-60. The muscle felt like it had tensed into a rock, and I could see it twitching under my skin. It was a charley horse, which is very unpleasant, effects any muscle but mostly the leg, and is an involuntary muscle spasm or cramp in nature.A charley horse can start suddenly and last anywhere from a few seconds to a few minutes. The pain can linger after the cramp goes away, and your muscle may feel sore for hours or even days. Muscle spasms can happen while you play sports or are exercising, or even when you’re just sitting still or lying down in bed.Symptoms of Charley HorsesThe defining symptom of a charley horse is muscle pain. The pain is often described as feeling like a hard, cramping knot, or spasm, within the muscle. And if you press gently on the muscle, you might feel a tender knot. In some cases, a visible twitching or hardening of the muscle may accompany the pain — hence the name. Charley horses are most likely to occur in the calf and thigh muscles, but you can get them in just about any skeletal muscle. Charley horses can last anywhere from a few seconds to a several minutes — or even longer. In rare cases, discomfort from a charley horse lingers for a day or two after the muscle spasm has resolved.Causes of Charley HorsesCharley horses happen when muscles in your leg or foot tighten up without warning and it can be really painful. There are a few reasons this might happen. One is if you’ve been using the muscle too much — like by doing lots of walking or running, especially on a hard surface, or by pointing your toes for an extended period of time. (You might get one if you’re wearing high heels, for example.) Muscles that are tired or dehydrated get tight, so make sure you’re drinking enough fluids during the day, even more if you’re sweating a lot.An imbalance of electrolytes, such as potassium and calcium, in your body can cause a muscle spasm. These minerals help your muscles contract and relax and work together for your muscles to function properly. If you have low levels of either of these minerals, you may have cramps or spasms. Certain nerves in your body control the contractions of your muscles. If these nerves become irritated, they can cause your muscles to contract too much leading to a spasm. A herniated disk in your spine, for example, may press against a nerve root causing pain and spasms in the back muscles. Stress also tightens muscles. Tension and muscle contraction can trigger both acute and chronic neck pain.Who is Most at Risk?Athletes are especially susceptible to charley horses in preseason as their bodies aren’t used to such heavy activity and it can also put endurance athletes, like marathon runners and triathletes, at higher risk because of the prolonged stress on their muscles.How to Relieve a Charley HorseCharley horses can be treated on your own at home and will usually resolve within 10 minutes. Here’s what you can do to help the pain.- Do not do anything or continue with the exercises you are doing, instead stop and stretch the muscle affected.- Gently massage the muscle to help it relax.- First apply a heating pad on the muscle and after the pain goes away, use a cold pack on the soreness.