In 50 percent of the cases, people with cerebral hemorrhages die of increased pressure on their brains. Those who live, however, tend to recover much more than those who've had strokes caused by a clot. The reason is that when a blood vessel is blocked, part of the brain dies and the brain doesn't regenerate. But when a blood vessel in the brain bursts, pressure from the blood compresses part of the brain. If the person survives, gradually the pressure diminishes and the brain may return to its former state.
High levels are a large factor in clogging arteries.
Your blood pressure is checked each time you donate and cholesterol levels are checked periodically.