When walking, hands swell primarily due to a combination of factors including arm movements, temperature changes, and blood vessel responses related to exercise. As you walk, your arms naturally swing, which can create a force that pushes fluid into your hands and fingers. Additionally, your body produces heat and increases blood flow to the skin to cool down, causing blood vessels in your hands to widen (vasodilation), which can lead to fluid leakage between cells and swelling. Other contributing factors include decreased blood flow to the hands during exercise as blood is redirected to muscles that need it most, and gravity causing blood to pool in the hands when they hang down at your sides. Wearing tight accessories like rings or watchbands can worsen the swelling. In rare cases, excessive fluid intake causing low sodium (hyponatremia) can also lead to swollen hands during exercise. To help prevent or reduce swelling, it is advised to remove restrictive items before walking, engage in regular arm and finger movements during exercise, drink fluids with electrolytes, and possibly wear snug compression gloves. This phenomenon is common and generally not serious, but persistent or painful swelling should be evaluated by a healthcare professional.