It is not uncommon for your feet or hands to become swollen when you
sit or stand for a long time in a hot environment (heat edema). Heat causes the
blood vessels to expand (dilate), so body fluid moves into the hands or legs by
gravity. The balance of salt in the body is also a risk factor for heat edema.
If salt loss is less than normal, the increased salt level draws fluid into the
hands and legs.
Older adults have an increased risk of heat edema, especially if they
have other medical conditions that affect their circulation.
People visiting hot climates from colder climates may also have an
increased risk of heat edema.