148/46 blood pressure, what does this mean?

I read that it could be isolated hypertension, but im 25, quit smoking almost a year ago. I workout 4-5 days a week, eat healthy. I'm 5'8" about 175#s, low body fat 8%. I don't have a stressful life either. Just wondering getting a little concerned its always high/low. I am pretty muscular, I was wondering if adding muscle would affect your bp and how it would show up? thanks for the help.