Do you have swollen feet or ankles after you’ve been sitting, standing or walking in a hot environment? You’re not alone. Medically known as heat oedema, this uncomfortable swelling generally occurs because the heat from your environment causes your blood vessels to naturally expand (dilate). As they do, fluid can leak into the surrounding tissues. Pair this with gravity encouraging the passage of larger volumes of fluid down into the legs, and you’ve got swollen feet, ankles and even legs.