Medically Approved

Why do my legs swell up in the summer?

Man fishing on a lake

For some people, heat and humidity cause legs to retain water and puff up. The condition is called edema. Here’s what you can do about it. 

Emily Shiffer

By Emily Shiffer

Summer is the season of sunshine and heat. Unfortunately for many people, it’s also the season of swollen legs, a condition called edema. We asked the specialists to explain what edema is, why it spikes in summer and how to treat it.

What is edema?

Swelling is caused by excess fluid in body tissue, says John Hogg, MD, founder of Medical Vein Clinic in San Antonio. “It can be specific to a particular body region or generalized throughout the body.” He notes that it tends to be slightly more common in women than men. (If you need medication to treat edema or another condition, Optum Perks can help you pay for it. Download our app to search for coupons up to 80% off.)

Edema can be a diagnosis, but it’s usually a symptom of something else. The underlying cause could be a disease, allergies or a reaction to new medication. And yes, it’s possible to develop new allergies later in life.

Edema can affect the eyes, lungs or even brain, says Mark J. Mendeszoon, DPM, a podiatrist and foot and ankle surgeon at Precision Orthopaedic Specialties in Chardon, Ohio. But it occurs most often in the lower half of the body. “Most people correlate edema to lower leg, ankle and foot swelling,” says Dr. Mendeszoon.

Why do I swell more in the summer?

It’s common to experience edema more severely on hot days. “As the temperature starts to rise, the heat may cause the lower leg vessels to dilate,” or open wider, says Dr. Mendeszoon. “That can cause fluids to leak out and get trapped underneath the skin.” With more fluid comes more swelling.

Another explanation for summertime swelling stems from the body’s interest in regulating your core temperature to prevent organ damage. As your heart pushes warm blood away from your intestines and kidneys, it can pool in the legs and arms, says Dr. Mendeszoon. (Learn how to spot signs of heatstroke.)

Should I be concerned?

That’s hard to say. Remember, edema is generally a symptom. So your first step should be to visit your doctor to find the underlying cause. If you’ve recently started a new medication, that will be one of the first places your doctor will look. He or she may recommend alternatives.

In some cases, edema could be harmless. In others, it could signal something serious. “Certain medical conditions make people more susceptible to fluid retention and heat-related complications,” says Elizabeth Detschelt, MD. She’s the director of vascular surgery at Excela Health in Greensburg, Pennsylvania. Here are some conditions your doctor will likely consider:

  • Cirrhosis
  • Congestive heart failure
  • Deep vein thrombosis
  • Diabetes
  • Kidney disease
  • Lung disease
  • Lymphedema
  • Severe, long-term protein deficiency
  • Thyroid problems
  • Venous insufficiency (or bad vein valves)

Of those, deep vein thrombosis is one that Dr. Hogg says is on the rise. This is a blood-clot disorder that usually occurs in the legs and can cause warmth and redness on the skin. The risk with DVT is that the clots can break loose and travel to the heart or lungs, which is life-threatening. “If a person has a recent increase in leg swelling, bulging veins or leg pain, they should immediately see their medical provider,” says Dr. Hogg.

One sign that your edema might be dangerous: You can see the memory of your fingerprint after you press into the skin. This is called pitting edema. “If a person notices they can press a finger into their leg and it leaves a deep dimple, they should seek medical attention,” says Dr. Mendeszoon. Other signs of serious edema include headaches, lightheadedness, shortness of breath and difficulty urinating.

Once you seek treatment, your doctor will be able to recommend treatment options that address the cause.

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Are there non-medical ways to treat edema?

Once you’ve ruled out serious problems, you might want to start reducing the swelling. Here are a few things you should try.

  • Wear compression socks. This is a common way to treat edema. “Compression socks can be purchased online or at a medical supply store,” says Dr. Detschelt. “Wear them like a normal pair of socks during the day. You do not need to sleep in them.” This can make a big impact on swelling, she says. Similarly, you can also look into compression boots, which are inflatable leg sleeves you can wear at home.
  • Elevate your legs. Use gravity to help blood flow back toward your core. You do this by elevating your swollen legs. “When sitting down, it may benefit you to prop your legs up on a recliner or on 2 to 3 pillows to get your feet above your heart level,” says Dr. Mendeszoon.
  • Give your feet a break. If you work standing up, the occasional break could help blood circulate away from your legs. “It would be beneficial to sit for 10 minutes once or twice a day during work,” says Dr. Mendeszoon. This is most effective if you’re also wearing compression socks and drinking plenty of water, he adds.
  • Cut the salty foods. Diet also plays an important role in keeping edema at bay. Foods high in salt and sodium may be part of the problem,” says Dr. Mendeszoon. Among the big offenders, he lists potato chips, noodles with “flavor packaging,” soy sauce, teriyaki sauce and flavored jerky.
  • Drink plenty of water. Being dehydrated can actually lead to more swelling, says Dr. Mendeszoon. He recommends that you drink ½ to 1 gallon of water on hot days. Your urine should run clear, with no odor. (As it turns out, the color of your urine says a lot about your health.)

How to prevent edema

Ultimately, you should take steps to prevent edema from happening in the first place. Here’s how to do it:

  • Improve your diet. People who are overweight are more likely to have edema, says Dr. Hogg. “Obesity is a huge risk factor for leg swelling caused by vein disease or lymphedema.” That‘s a chronic form of edema resulting from blockages in the lymphatic system, which your body uses to fight infections and remove waste. (Taking a diuretic or water pill to manage swelling? These healthy-eating tips can help you get the most from your medication.)
  • Take medication as prescribed. If you have heart, liver or kidney disease, take your medications exactly as your doctor tells you to. Deviating from the plan makes it hard to determine whether the problem is the medication or the way you’re using it.
  • Stay active. “Walking, biking and swimming will strengthen the heart and leg muscles,” says Dr. Mendeszoon. “That may help with circulation issues and improve blood flow back to the heart.”
  • Talk to your doctor or visit a vein specialist. “If you notice varicose veins, or spider veins, then a consultation with a vein specialist can be useful,” says Dr. Mendeszoon. The doctor can evaluate your veins and valves, and you might be able to reduce the risk of swelling with a minimally invasive corrective procedure.

Bottom line: See your doctor

If you’re running a fever, you visit the doctor to find out why. You should treat edema the same way. “Some causes of edema can be treated, and the edema can get better or completely resolve,” says Dr. Detschelt.

You might not be able to eliminate the swelling in every instance. But at the very least, you want to rule out more serious conditions.

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Additional source
Edema overview: Cleveland Clinic