. >> peopople with pvpv, like deba trenently and d merle wertmaman, suffer from an overproduction of red blood cells. >> so the blood gets very thick, and it can cause, you know, blockages to smaller blood vessels that feed vvital organss of our body. tissue deathanan occur anywhere in ththe body. itit can occur in their r brain, it can occur in their toe, it can occur in their liver. we've seen patients where they've developed infarctions to their feet, where they've had to hahave toes amputated. they have infarctions to theirr liver. they can have an infarction to their heart, much like a heart attack. >> the way it works on you, you're so exhausted and tired, you have chronic pain everywhere. i h have chronic fatigue. headaches, , terrible. it affects your vision. i'llll just wake up and haveve s in my legs and my hands and my feet. it's vascular, so it goes through every part, every vein on your body, you're having a lot of pain, every direction. you u don't knowow where t to pt yoyourself. >> for merle, who has been a sports fanatic all his life, pv has really changed his once a