While the growth plates in the feet close in early adulthood, the overall size and shape of the foot often continue to change throughout a person’s life, resulting in an increase in length and width. This change is not due to true bone growth but rather a structural redistribution caused by the continuous forces placed on the feet over decades. Many people experience an increase of a half-size or more over their adult years.
Why Foot Structure Changes Over Time
The primary mechanism behind foot enlargement with age is the gradual deterioration of the supportive structures. The constant, chronic pressure of standing and walking subjects the foot’s architecture to years of gravitational force. This lifelong impact causes the tendons and ligaments that maintain the foot’s arch to slowly lose their tensile strength and elasticity.
This loss of stiffness, known as ligament laxity, leads directly to a lowering or flattening of the medial longitudinal arch. As the arch collapses, the foot pronates. The posterior tibial tendon, which is the primary stabilizer of the arch, is particularly susceptible to age-related wear and tear, and its weakening is a common cause of adult-acquired flatfoot.
The protective fat pads located beneath the heel and the ball of the foot undergo atrophy over time. This thinning of the adipose tissue reduces the natural cushioning, which can alter how pressure is distributed across the foot’s bones and joints. The resulting biomechanical changes can lead to joints splaying out, further contributing to the foot’s overall spread and requiring a larger shoe size for comfort.
Major Factors That Influence Foot Size
External forces and health conditions can significantly accelerate the natural, age-related changes in foot size. Weight gain is a substantial factor, as increased body mass directly translates to greater load on the foot’s arches and ligaments. This amplified pressure hastens the stretching of the supportive tissues, leading to a faster rate of arch collapse and foot spreading.
Hormonal fluctuations are another common cause of adult foot change, particularly in women. During pregnancy, the hormone relaxin is released to loosen ligaments in preparation for childbirth, but this effect is systemic and also affects the ligaments in the feet. Coupled with the temporary weight gain and edema, this can result in a permanent widening or lengthening of the foot structure postpartum.
Certain medical conditions also influence foot dimension and shape. Conditions such as diabetes can lead to peripheral neuropathy, which may cause structural changes and deformities, requiring specialized or larger footwear. Arthritis, especially osteoarthritis, can cause joint stiffness and the development of bony growths, such as bunions, which increase the width and overall volume of the foot. Swelling, or edema, often associated with circulatory issues, also increases foot size, making previously comfortable shoes too tight.
Practical Steps for Addressing Foot Size Changes
Regular measurement is important to ensure proper shoe fit and comfort. Have your feet measured every few years, as size and shape can shift without obvious notice. When measuring, measure both feet, as age-related changes often lead to an increase in asymmetry between the left and right foot.
When selecting footwear, prioritize shoes that accommodate the foot’s new dimensions and structure. Look for styles with a wider toe box to prevent compression and the development of deformities like bunions. Selecting shoes with adequate arch support can help manage the lowered arch and better distribute pressure across the sole.
Replacing older, worn-out shoes is also beneficial, as the support structures within the shoe itself degrade over time. If foot changes are accompanied by persistent or sharp pain, or if the size increase is rapid, consulting a podiatrist is recommended. A foot specialist can assess the underlying cause and recommend appropriate interventions, such as custom orthotics, to provide tailored support.