The reasons why patients wake up with sore feet are as follows: First, acute foot muscle injury: for example, if you have strenuous sports during the day, there will be leg muscle strain, there will be leg muscle bleeding, and there can also be local accumulation of lactic acid in the leg and foot muscles, so it can be manifested as local soreness, sometimes accompanied by cramps, and this symptom will be especially obvious when you sleep at night or just wake up. Second, calcium deficiency: calcium ions can inhibit the excitability of the neuromuscular junction, and when calcium deficiency increases the excitability of the neuromuscular junction, there will often be hand and foot twitching or calf cramps and soreness, also at night when the symptoms will be particularly obvious.