Blood is mostly made up of water, as are our organs and muscles. To read specifically about edema, swelling caused by fluid retention where excess fluid is trapped in the body's tissues, see our article Edema: Causes, Symptoms and Treatments.
If you use the Amsoil Ea15K01 and the ASM oil (For 3rd gen Prius), then you can safely go 15,000 miles between oil changes. I drive 25,000 miles per year in my Prius. Amsoil backs up their products by a written warranty.
It makes me depressed. You do the math and keep it to yourself. At any rate, enough about my mid life crisis. Let's talk about oil change intervals. For years the accepted oil change interval (as per the carmakers) has been every 3 months or 3 thousand miles, whichever comes first.