When blood pressure stays too high, for too long, it puts strain on the blood vessels supplying the heart, brain, kidneys and other organs, and over time this can cause damage to, and even disease in, the arteries.
Article source: https://www.huffingtonpost.co.uk/entry/high-blood-pressure-reading-cardiologist_uk_6ae36f1be4b0a2cccd46e78c