Nocturnal leg cramps refer to painful contractions of the leg muscles, typically in the calves, that happen during the night while at rest. According to the Cleveland Clinic, nocturnal leg cramps are found in anyone, with individuals in middle-age or older being most susceptible. Relieving the cramps involves moving or stretching the pained muscle or applying ice to the area of discomfort. The exact cause of nocturnal leg cramping is uncertain; however, factors such as medical conditions or strains play a role.
Overexertion
Overexertion of leg muscles from athletic activities, such as running, can lead to nocturnal leg cramps. This happens, in part, due to exaggeration of normal muscle movement through flexing and extending the foot during high-intensity exercise. Overexertion is more plausible when proper stretching is not done prior to beginning exercise. Sleep Disorders Guide explains that during a sleep state, turning or movement causes the calf muscles to contract and stretch the tendons. Nerve damage or muscle damage from overexertion can force the legs to stay contracted, leading to painful cramping. The Cleveland Clinic suggests stretching the leg muscles prior to going to sleep to prevent cramping.
Dehydration
Excessive loss of fluids, or dehydration, leads to nocturnal cramping. MayoClinic.com explains that dehydration occurs when more fluid is excreted than is taken in by the body. Dehydration can further lead to electrolyte imbalance; this refers to the levels of sodium, calcium or potassium minerals maintained by the body. Calcium deficiency is a common factor found in people experiencing persistent leg cramping. Dehydration and loss of essential electrolytes result from excessive sweating or increased urination without fluid replenishment. The NYU Langone Medical Center suggests drinking clear fluids such as sports drinks or water every half hour and avoiding caffeinated beverages or sweetened drinks to reduce risk of nocturnal leg cramping.
Positioning and Sedentary Lifestyle
Foot and ankle abnormalities, such as flat feet--an absence of the normal arch of the foot--can cause nocturnal leg cramps. According to NYU Langone Medical Center, standing for long periods of time on flat feet without support can overextend leg muscles and cause later cramping. Sitting for long periods of time without stretching can also lead to nocturnal leg cramps. The Cleveland Clinic suggests spending a few minutes a night riding a bike or engaging in light activity with the legs, including stretching, to reduce the chance of cramping.
Medical Conditions
In rare cases, medical conditions such as diabetes, or the use of diuretic medications can lead to nocturnal leg cramps. MayoClinic.com notes that diabetes--a condition affecting the way the body metabolizes sugar--can cause nerve damage of the extremities and poor blood flow to the feet. Consequently, this increases the risk for developing night cramping. Use of diuretic medications, which increase urine output, leads to risk for dehydration and loss of electrolytes, in turn causing nocturnal leg cramps.
