For the causes of sore legs at night, the specific reasons are as follows: First, a lot of sports or physical labor: it will cause a large amount of lactic acid to accumulate in the legs, which leads to muscle soreness and pain, and this soreness and pain will be especially obvious at night, especially in a quiet state. Second, calcium deficiency: calcium ions can inhibit the excitability of the neuromuscular junction. When calcium deficiency occurs, the excitability of the neuromuscular junction will increase, and twitching of the hands and feet will occur. The most typical symptom in adults is spasmodic pain in the gastrocnemius muscle at night, also known as calf cramps. Early monitoring of blood calcium levels is required, and if it is clear that blood calcium is lowered, calcium should be actively supplemented, and more sunshine should be provided to solve the problem of leg soreness at night.