Moderate exercise is often recommended to help increase blood flow, strengthen muscles and bones, and promote overall health and well-being. Therefore, when you notice swelling after your workouts, it can be a cause of confusion and concern. Swelling, or edema, in the legs and ankles is not necessarily unusual, and it can be caused by a number of factors.
It's normal for parts of the body to swell during and after exercise. According to Robert H. Shmerling, MD, this phenomenon is associated with vasodilation. During exercise, the blood vessels open up to allow increased blood flow. This can cause the hands, face, legs and feet to enlarge slightly and even appear swollen. Vasodilation typically recedes on its own after your body cools down.
Hormonal response can be responsible for swelling in some people, particularly women. According to the National Library of Medicine, women who take estrogen supplements may be more prone to swelling. Pregnant women are also susceptible to swelling due to an overall increase in estrogen levels as well as increased blood volume and water retention throughout the body. Because exercises such as walking, jogging and hiking encourage the natural effects of gravity, much of the body's fluids naturally pool in the lower legs, ankles and feet during physical activity and thus may result in swelling.
You may develop swelling if you have a previous injury not yet healed or you are recovering from a recent surgery of the legs or ankles. Stress fractures can also cause swelling. If you run or walk a great deal, inflammation in the joints due to arthritis or irritation from tendinitis or synovitis can also present as swollen ankles.
Although swelling of the legs and feet can be a sign of organ failure, it's not likely, particularly if the swelling only occurs following a workout. In cases of heart, liver or kidney failure, the organ typically fails in its responsibility to cycle fluids throughout the body. These excess fluids then create edema that can manifest as swollen ankles, hands and feet. For safety's sake, check with your doctor if you have any concerns.
If you've ruled out organ failure and injury as possible causes, you need not be alarmed as long as the swelling is manageable and subsides after a few hours. If your ankles do not return to normal size, you should consider taking a rest from your workout routine to allow time for healing. You can also apply ice to the affected area, or soak your feet and ankles in a bath of ice water and epsom salt. Consider getting fitted for proper athletic shoes with a reputable shoe outfitter as well. Well-fitting shoes can help ensure your gait is steady and less prone to injury.