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.
Hair grows about 1/2 inch per month. If the rest of the scalp hair is long, it may take months or years before a shaved area grows sufficiently to match the rest of the hair. After shaving, the hair growing back may appear to be thicker and coarser, because the shaving process removes the natural thin ends of the hair. Eventually, the shaved hairs are shed and replaced with normal hair. Scalp hairs may only be shed every two to six years. Scalp hairs grow continuously most of the time.