• Varicose veins typically first appear in the feet and calves.Stockbroker/Valueline/Getty Images
  
  Varicose veins, those spindly purple veins common among middle-aged and older people, affect approximately 50 percent of the American population over the age of 50, according to the National Institutes of Health. Routinely poor or strained blood flow stretches and weakens the vein walls, causing blood to pool and creating the bulging curly appearance of the varicose vein. The prevalence and severity of varicose veins is not the result of a single factor but a combination of weight, age, lifestyle and genetics.
  
  

Age

• As you age, your cells and tissue loose their elasticity causing wrinkles, sagging and potentially varicose veins. Strong vein walls allow blood to pump efficiently from your lower body back to your heart. As your cells lose elasticity with age, blood begins pooling in your lower legs causing vein walls to bulge and contort against your skin creating varicose veins. Just like other signs of aging, genetics plays a role in determining how early your elasticity begins declining.
  
  

Sedentary Lifestyle

• Whenever you sit or stand still your body works to circulate the blood from your leg veins back to your heart. Occupations requiring you to stand on your feet for long periods, such as cashiers or restaurant hostesses, can increase your chances of varicose veins. If you sit at a desk much of the day, your veins and vein walls strain to constantly push the blood upward. Sitting with your legs crossed increases this pressure by further restricting your circulation. Long periods of strain or of lack of movement in your legs weakens the vein walls and can cause varicose veins.
  
  

Obesity

• Being overweight taxes your heart and circulatory system which must work harder to sustain and move your larger body size. The stress of your heart, in turn, affects other areas of the circulatory system such as the veins and capillaries. Chronic strain and pressure on your veins causes walls to loosen, allowing blood to pool and ultimately causing varicose veins.