Weight is a good guideline for blood volume in people of average build. This is why we set a minimum weight limit of 7st 12lbs (50 kg) because if more than 13% of blood volume is taken there is more risk of the donor feeling faint after donating.
Not surprisingly, the one factlet most often offered up as revealed truth is wholly false: Your hair and nails do not continue to grow after you die; it's all optical illusion. The sorry fact of the matter is that we dehydrate after dying. Our flesh dries and, in so doing, pulls away from nails and hair.
The hair on your head grows about six inches per year on average, or about half an inch per month. Each hair grows for about two to six years then stops and enters the telogen phase, during which it is gradually shed. On average, you lose about 50 to 100 hairs per day. Often, the growth cycle of the follicle starts over and a new hair begins to grow in after one is shed.