blood hypertension have multiple causes. some of then you can control (smoking, diet, body weight), some times another disease can cause it (like a tumor on the adrenal gland) and some you can't control (old age...). how to treat? 2 steps...but i'll let you read about it from a very reliable medical site:
http://familydoctor.org/online/famdocen/home/common/... good luck!