When your feet swell from the heat, this is the result of oedema, which is the accumulation of excess fluid. Swelling, generally speaking, is either the result of a collection of body fluid or tissue growth or abnormal positioning or movement of tissue, according to Peacehealth.org.
Most of us know us when our feet swell. They become tight and uncomfortable. Your skin will become stretched and shiny. If your swelling is heat-related, swelling is a temporary condition. Once you get out of the heat and prop up your feet, the swelling should go down. If you're not quite certain if there is swelling present, but suspect it, press your thumb into your foot and apply steady pressure. If oedema is present, you will see an indentation in your skin.
Heat oedema is considered the mildest for of heat-related conditions, according to Dr. Michael W. Barrow and Dr. Katherine A. Clark of Wright State University School of Medicine, Dayton, Ohio. Foot swelling, or swelling of other body parts, is the result of transient peripheral vasodilation, which is caused by the heat as well as from orthostatic pooling, which occurs when a person stands or sits too long. If you are not accustomed to hot weather, this means that you are unacclimatized to the warm climate and this can result in swelling.
What heat does
Heat makes your blood vessels dilate (expand). Body fluids then move to your legs, feet and hands via gravity. According to Jan Nissl, RN, BS, of Health.msn.com, if the salt balance in your body is off kilter, this can increase the risk of heat oedema. If your salt loss is less than what it should be, the excessive salt level will draw fluid into your extremities. If you are elderly, you are more at risk for experiencing heat oedema because you may have other physical problems that have affected your circulatory system.
Dr. Derek Smith of Stillwater, Oklahoma and Prweb.com notes that hot weather makes some foot problems even worse. Feet are usually stuck inside of shoes so perspiration is a big factor. Skin can get soggy and unhealthy when it reabsorbs moisture. The risk of developing blisters and being targeted by microbes is great because of this environment. Heat also makes friction worse, which can contribute to the development of calluses, eczema and psoriasis.
If it's hot, make sure that you wash your feet daily and dry them carefully, especially in between the toes. Be sure to stay hydrated but don't drink too much because this will promote swelling. Wear shoes that let your feet breathe, including open-toe styles or sandals. Change your shoes and socks frequently. Consider using a foot powder to keep your feet dry.