There are several reasons for feeling sore and tired in the calf area while sleeping. 1. Due to excessive leg activities during the day, such as walking too much, long distance walking, and strenuous exercise, it may cause the local muscle tissue to consume more energy, nutrients, and electrolytes, which may lead to local soreness and tiredness due to electrolyte deprivation, and due to the inflammation and lactic acid generated after more activities. 2. 2, during the night sleep, may be due to the leg muscles are not fully relaxed, so that after a long time will lead to muscle fatigue, or even the formation of strain, will also appear particularly sore and tired feeling. 3, because the legs are not adequately warm at night, such as open air conditioning, fans, doors and windows, lack of clothing cover, these reasons. Lack of clothing cover, these reasons will lead to the calf area appear cold situation. After the cold, the muscle tissue becomes more tense, and will lead to more and more lactic acid and inflammatory metabolites produced locally, which will lead to the sore and tired feeling more obvious.