Feet swell in the heat primarily due to a process called heat edema. When exposed to hot temperatures, blood vessels in the feet dilate (expand) to help release heat from the body. This dilation allows more blood flow close to the skin but also causes fluid to leak into surrounding tissues, leading to swelling. Additionally, gravity pulls fluids downward into the feet and ankles, especially if standing or sitting for long periods, which worsens the swelling. Heat can also cause the body to retain salt and water, further contributing to fluid accumulation in the feet. Other factors like poor circulation, venous insufficiency, dehydration, and certain medical conditions can increase susceptibility to this swelling in hot weather.
Key Reasons for Feet Swelling in Heat
- Vasodilation: Blood vessels expand to cool the body, causing fluid leakage into tissues.
- Gravity: Fluids pool in the lower extremities when standing or sitting.
- Salt and Water Retention: Heat disrupts salt-water balance, leading to fluid buildup.
- Reduced Movement: Lack of muscle contraction impairs blood return from feet.
- Dehydration: Causes the body to hold onto fluid, worsening swelling.
- Pre-existing Conditions: Circulatory issues and certain health conditions increase risk.
Who Is More Prone to Heat-Related Foot Swelling?
- Older adults, pregnant women, people with venous insufficiency or circulation problems.
- Individuals standing or sitting for long periods in heat.
- Those with medical conditions affecting the heart, kidneys, or thyroid.
- People who consume excess salt or certain medications that cause fluid retention.
This understanding helps explain why feet swell in hot weather and highlights factors that aggravate the condition.
