October 11 (HealthDay News) -- Acting U.S. Surgeon General Dr. Steven K. Galson recently released a "Call to Action" to reduce the number of cases of deep vein thrombosis and pulmonary embolism in the United States.

The American Physical Therapy Association (APTA) said it supports this initiative and offers tips for preventing these life-threatening conditions during air travel.

A blood clot, called a deep vein thrombosis (DVT), can occur after long periods of being immobile, such as on long plane flights, according to Susan Scherer, associate professor of physical therapy at Regis University in Denver and a member of the APTA.

If a DVT occurs, the clot may dislodge and travel to the lungs, a condition called pulmonary embolus.

Symptoms of leg DVT include swelling in one or both legs and calf tenderness. People with pulmonary embolus symptoms may experience shortness of breath and increased heart rate.

"People who experience any of these symptoms should always see the doctor, especially if they occur following a long period of immobilization," said Scherer in an APTA news release.

To reduce the risks of DVT in flight, Scherer said people should wear compression stockings to keep excess blood from remaining in the legs. In addition, she advised seated exercises to keep the blood flowing, the joints mobile, and the muscles relaxed.

"Simple exercises can help prevent other typical symptoms experienced by people who fly, including leg cramping, toe cramping, and general lower-body aching," said former APTA President Marilyn Moffat in the news release. "Sitting for long periods may lead to swelling of the feet, which becomes obvious to many passengers when they try to put their shoes back on at the end of their flight."

The APTA suggests that passengers on long flights get up and walk up and down the aisle every hour or so -- when the "Fasten Seat Belt" sign is off -- to work the leg muscles and ease the back.

"Performing these exercises will keep the leg muscles from contracting and will help relieve stiffness from the flight. The exercises also will help prevent fluid build-up in the legs, and stretching the back and the muscles around the torso will prevent stiffening," said Moffat.

Finally, since dehydration may occur during a flight due to high altitudes and dry, pressurized cabin air, the APTA advises that passengers drink plenty of water before and during the flight to help prevent muscle cramping and aching due to dehydration.

SOURCE: American Physical Therapy Association, news release, Sept. 29, 2008