"Tired feet" are not a medical condition, but are a common complaint related to various medical conditions. Abnormal foot structure (flatfoot or high arched foot) can overburden the foot, resulting in muscle fatigue. Obesity, improper footwear, pregnancy, leg swelling, increased activity level, or compensation from an injury (through overuse of other parts of the foot and/or the opposite foot) are other potential factors in the development of tired feet.