blood clots...

About 15% of the population is prone to bloodclots due to hereditary factors. The most common one is called Factor 5 Leiden.

Both my parents suffered from DVT (deep vein thrombosis), my sister does and my uncle dropped dead at 42 from a blood clot to the brain.

Guess what? I am prone to it as well, and ended up in the ICU with both legs clotted up all to heck and bi-lateral pulminary embolisms. If you have family members with DVT's, get a blood test to see how your clotting.

Symptoms: painful lines on the legs, Most people complain of severe pain, but mine weren't too bad until there was no blood flowing at all. Horribly short of breath.

To prevent, move the legs! The only way to actively return blood out of the legs is through walking or motions similar. Lift your toes, bear down on your heels. Daily baby aspirin helps, and compression socks help A LOT. If you are prone to a little swelling anyway, buy some 20 mg Hg compression socks, and you will feel so much better at the end of the day!