Cholesterol is substance found in the fats in your blood. Having high cholesterol can increase your risk of heart disease because it causes the obstruction of your arteries and make it difficult for blood to flow through them. Furthermore, decreased blood flow to your brain can cause a stroke. High cholesterol con be inherited, but it is often the result of unhealthy lifestyle choices, so it can be prevented with a healthy diet and exercise. High cholesterol has no symptoms and a blood test is the only way to detect it.