Sore and sleepy legs and weakness in summer are usually related to factors such as prolonged air-conditioning, calcium deficiency and hypokalemia. 1. Prolonged blowing of air-conditioning: In summer, when the weather is hot, if you often blow the air-conditioning and pay no attention to keep warm, it may make the lower limbs cold and cause poor blood circulation in the lower limbs, thus making the legs sore and weak. 2. Calcium deficiency: If the nutritional intake is affected in summer due to lack of diet, it may lead to lack of calcium intake, which is easy to cause weakness of legs if not supplemented in time. 3. Hypokalemia: summer sweating is more, the consumption is too large, if not timely supplementation of fluids, may cause hypokalemia, easy to cause water-electrolyte disorders, and ultimately, there will be symptoms such as legs sore and sleepy, weakness. Sore and sleepy legs and weakness may also be related to arthritis, rheumatism, lumbar intervertebral disc herniation and other factors. At present, it is recommended to consult a doctor as soon as possible, analyze the cause of the disease and follow the doctor’s instructions to standardize the treatment.