Hand swelling during exercise is common. The cause isn't completely clear. It appears to result from the way your body and blood vessels react to the higher energy needs of your muscles during exercise.

During exercise, more blood flows to your heart and lungs and to the muscles you're working. Less blood may flow to your hands, making them cooler. The blood vessels in your hands may react by opening wider. This could lead to hand swelling.

As you exercise, your muscles make heat. Your body pushes blood to the vessels closest to your skin to let the heat out. This action causes sweating. It also may make your hands swell.

Sometimes, high-level athletes develop hyponatremia (hi-poe-nuh-TREE-me-uh). This is an unusually low level of salt, also called sodium, in the blood. Swollen fingers and hands may be a sign of hyponatremia. Other signs, such as confusion and throwing up, may stand out more than the swelling. Hyponatremia is a serious condition that needs medical treatment right away.

There's no proven way to prevent or reduce most exercise-related hand swelling. But these tips may help ease trouble:

• Take off your rings and loosen your watchband before exercise.
• Circle your arms forward and backward at times during exercise.
• Stretch your fingers wide, make fists and raise your hands higher than your heart several times during exercise.
• When walking, use a hiking pole to keep your hand muscles squeezing.
• Wear gloves that are snug but not too tight.
• Drink liquids that have some salt in them while exercising, such as a sports drink that has electrolytes.