Why Legs Swell in the Heat (and How to Prevent It)

Heat waves are sweeping the country, and if you follow the news, you’ve heard stories about the dangers that come with it. From severe dehydration to heat stroke, the effects of extreme heat are serious. They can also be bothersome, as is the case with heat edema, the common condition of swollen skin in the summer, especially in the feet and legs.

Why do so many people’s legs swell in the heat? The short answer is gravity. Heat dilates (expands) our blood vessels, making it harder for fluids to move through our bodies. Since our feet and legs are the farthest from the heart, the fluids passing through them tend to pool up instead of pass through easily, resulting in swollen, stretched, or shiny skin. Everyone is susceptible to heat edema, and overweight individuals or those who aren’t accustomed to hot temperatures are at greater risk, so it’s important to know the dangers involved and the best methods of prevention.

The largest preventable cause of heat edema is dehydration. It’s always important to drink at least 64 ounces of water a day, and it’s a good idea to drink even more in the heat. Carry a reusable water bottle with you on hot days and try drinking it every hour. Salt-heavy diets also play a large role in dehydration and heat edema. Avoid salty snacks throughout the summer and try cutting a pinch from your home cooking.

Another cause for leg edema we commonly see is lack of activity. Occupations that require standing or sitting for long periods of time are more inclined to suffer from swelling. Particularly if you add a dose of summer heat into the situation. If you’re fortunate enough to work inside, stay indoors as much as you can when temperatures rise above 90 degrees. Add intermittent activity into your day by walking to the break room every 2 hours. Stuck to a desk all day? Add toe raises and heel raises under your desk to get the circulation going. Our calf muscles assist circulation and fluid back up the leg, so movement that includes the calf muscle pump will help.

Already have swollen legs? Contact your primary care physician or a vascular surgeon for an evaluation as soon as possible. Many things can cause leg swelling. Some are more serious than others. A prompt evaluation is advised.

Once it is determined there is no serious health risk from your leg swelling, you can manage the edema with the following guidelines.

1. Wear compression hose at strength of at least 20-30mm/Hg throughout the day.

2. Ambulate for at least 10 minutes several times per day.

3. When home relaxing, lay down with legs elevated above your heart.

Fortunately, most cases of leg edema are simply irritating and uncomfortable. No one likes to have swollen, achy skin. Unmanaged, long term leg swelling can lead to skin irritation, blisters and eventually wounds. Early evaluation will prevent progression. If you have more questions about heat edema, leg swelling or lymphedema, please give us a call at 866-695-8346. We’ll be happy to discuss your concerns at length.