Whether driving or flying, folks will sit motionless for hours putting them at an increased risk for something most are unprepared for and have never heard of DVT or deep vein thrombosis, a blood clot that could become deadly.
Frequent road trips home during college were a part of life for Mallory Click.
''I was trying just to drive straight through and get there, and you know, just so I wouldn't be wasting time driving.'' said Click.
But the five and a half hour trips nearly took her life at age 21.
''My leg was just throbbing and I had a hard time sleeping that night and I was just kind of tossing and turning all night,'' she said.
The pain and swelling were caused by deep vein thrombosis, a blood clot in her leg that nearly doubled its size - seen here- and sent her to the emergency room.
''It's crazy. I would have never thought at such a young age I could get blood clots,'' Click said.
DVT impacts 2 million each year in the U.S. and Dr. Heather Hall says most people know nothing about it or its risks.
''It's when that clot breaks off and travels to the lung and becomes a Pulmonary Embolism that it can be fatal,'' Hall said.
Every year, DVT kills more than 100,000 Americans, more than breast cancer and aids combined.
''Anything that makes a person less active or less mobile is going to put them at risk for developing a DVT,'' Hall said.
Her best advice when traveling? If you're driving, stop every four hours to stretch your legs and gets your blood flowing.
''If you're stuck on a flight and you can't get up and walk, something you can do is just sit in your seat and do calf raises. So raise, keep your toes on the floor, and raise your heels up and down," Hall said.
She also advises patients to avoid alcohol to stay hydrated during a flight.
It's also important to know your risk factors.
''Are you a smoker, are you overweight, do you have a family history of developing blood clots," Hall says.
All things Mallory is aware of now.
''I'm very lucky to still be here,'' she said.
Birth control pills, being overweight and smoking can also increase your risk of dvt. If you experience sudden pain and swelling in your calf or leg, doctor hall recommends that you see a doctor immediately.