Andrew Huberman· PhD
Now, lymphedema can occur for other reasons, and it has various stages. It's actually been mapped out. I'll provide a link to this. But there's Stage 1, 2, 3, and 4. And to briefly summarize, Stage 1 is asymptomatic, so the lymphatic system has some abnormal flow, but no real fluid buildup in the tissue that you necessarily see. Might be just slight swelling. In Stage 2, you see swelling due to accumulation of the lymph fluid, and that may subside if you elevate that limb. So, if you're getting some swelling of the ankles, for instance, you put your legs up and it disappears after putting your legs up for 20 or 30 minutes, then it's so-called Stage 2 lymphedema. Stage 3 and 4 are where you get a more permanent swelling, so an accumulation of fluid and waste products in that interstitial space, that extracellular space, and that's when things start to become problematic, because that buildup of fluid and waste products leads to a local immune response, which then causes thickening of the tissue above it, which then makes it even harder to clear out waste products, and the whole thing starts to cascade.