Suggest Remedy For Elevated Blood Pressure

My blood pressure has been 138/99. Iam a 37 female. I drink 6-7 dr peppers a day, no water, don't really excerise. The past 4 days I have cut down to 1 dr pepper a day, I've been drinking 4-5 bottles of water & walk 15 min twice a day. My BP is still the same. Does it take awhile for it to lower??