This is for my husband, an active, fit, 38 year old. His legs turn very blue every time he leans his hips back against something, such as the kitchen countertop. It happens quickly, within 20-30 seconds, and goes back to normal within 20-30 seconds of standing normally. It also happens when he squats or crouches down for a period of time, but that is more common so it's not as alarming. But how could leaning his hips against something make his legs blue? I've just about got him convinced to make an appointment with his doctor to talk about it. It's been going on at least a year now, but it doesn't cause any pain so it's easy for him to ignore.