Hi Thanks for your query. Cramps are caused by hyper excitability of the nerves that stimulate the muscles. They are overwhelmingly the most common type of skeletal muscle cramps. Cramps at rest are very common, especially in older adults, but may be experienced at any age, including childhood. Rest cramps often occur during the night. While not life threatening, night cramps (commonly known as nocturnal cramps) can be painful, disruptive of sleep, and they can recur frequently (that is, many times a night, and/or many nights each week). The actual cause of night cramps is unknown. Sometimes, such cramps are initiated by making a movement that shortens the muscle. An example is pointing the toe down while laying in bed, which shortens the calf muscle, a common site of muscle cramps. The cause of cramps is as following- 1. Low blood levels of either calcium or magnesium directly increase the excitability of both the nerve endings and the muscles they stimulate. This may be a predisposing factor for the spontaneous true cramps experienced by many older adults. Cramps can also occur in excessive vomiting, dehydration. 2. On drugs which causes excessive urination. Leading to low calcium. Magnesium potassium level. Drugs given for asthma, angina and Parkinsonism also lead to cramps. 3. Several vitamin deficiency states may directly or indirectly lead to muscle cramps. These include deficiencies of thiamine (B1), pantothenic acid (B5), and pyridoxine (B6). Most cramps can be stopped if the muscle can be stretched. For many cramps of the feet and legs, this stretching can often be accomplished by standing up and walking around. Gently massaging the muscle will often help it to relax, as will applying warmth from a heating pad or hot soak. If the cramp is associated with fluid loss, as is often the case with vigorous physical activity, fluid and electrolyte (especially sodium and potassium) replacement is essential. Certain drugs like baclofen are helpful. A simple way to prevent night cramp is stretch your calf muscle before going to bed 3-4 times and each time holding for 10-15 seconds. Quinine water tonic is also useful to prevent night cramps before going to bed I hope this information will be helpful to prevent night cramps. If you have further query I shall be glad to answer. Take care Regards