Charley horses, or night calf cramps, are caused by sudden, involuntary muscle spasms in the calf muscle, often occurring during sleep. The exact cause is frequently unknown, but several factors contribute to their occurrence:

• Muscle fatigue or overuse, such as from intense exercise or prolonged standing.
• Poor blood flow to the muscles.
• Nerve-related issues, including abnormal nerve signals or pinched nerves in the back or neck.
• Dehydration and electrolyte imbalances, particularly low levels of magnesium, potassium, or calcium.
• Inadequate stretching or muscle shortening, especially when the foot is in a plantar flexion position (toes pointed away), which shortens calf muscles during sleep.
• Certain medications like diuretics, statins, and asthma drugs.
• Medical conditions including kidney disease, diabetes, thyroid disorders, and pregnancy.
• Aging, which can lead to loss of motor neurons and muscle changes.

Charley horses tend to be more common in older adults, athletes, pregnant individuals, and those with certain health conditions

. Relief is usually achieved by stretching or massaging the affected muscle, and prevention includes staying hydrated, stretching regularly, avoiding prolonged inactivity, and addressing underlying health issues