You don’t know either. I was trying to bluster an answer to my 9 year old when she asked what a blood pressure machine was for. I realised I didn’t know.
I have looked it up for you on the Blood Pressure UK site;
“If you have high blood pressure, this higher pressure puts extra strain on your heart and blood vessels. Over time, this extra strain increases your risk of a heart attack or stroke. High blood pressure can also cause heart and kidney disease, and is closely linked to some forms of dementia”.
Usual solutions exercise, don’t drink and eat too much.
They are always the same.