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.
Advances in oil chemistry and engine technology and an increased use of synthetic oil have lengthened oil change intervals significantly. For 2013 models, autumakers advise drivers to change their oil every 7,500, 10,000, or even 15,000 miles. The shortest oil change interval is 5,000 miles but only in some Hyundai and Kia models. However, the car service industry continues to tell customers that they need to change their oil twice as often.