Science says your feet can swell by evening and physics is the reason, here’s why your shoes may feel tighter at night

Changes in foot size throughout the day are a simple example of biomechanics and cardiovascular physiology working continuously without conscious effort. When you stand or sit for long periods, gravity increases hydrostatic pressure in the lower limbs, encouraging fluid to move out of capillaries into surrounding tissues. Starling forces help regulate this fluid exchange, while the lymphatic system clears excess fluid and muscle contractions assist in pushing venous blood back toward the heart.