BP readings vary greatly

Hi, I am a 38 year old slim male who has been struggling with my blood pressure for about 8 years. On my latest doctor visit I got a high reading of 152/98, which is among one of the highest readings I have received. I was prescribed lisinopril which I have not started yet.

The reason I have not started medication is that I am finding that my blood pressure varies greatly. For example, most mornings it ranges in the low 120/80 range, sometimes lower. In the evening it can be around that level as well although typically I see 125/85 ish. However, sometimes it can be pretty high. For example, last night after dinner as I was driving home I started feeling a bit “off”. When I got home I rested for 5 minutes then took my bp, it was 148/97. I laid down for about 20 minutes and took again 119/79. Took it a couple more times during the evening and it remained in the normal range.

This has been my typical experience over the past few years which is why I have not been prescribed medication until this last visit. To be fair I have not done all I could in regard to exercise and diet. My diet is fairly healthy but could be improved. I typically exercise much more during spring, summer and fall than winter so I have been lax in that department lately. During my 20's and very early 30's I had been a pretty heavy drinker although in the past 5 to 6 years I have reduced my intake dramatically. I have had fairly comprehensive blood and UA lab work done with no abnormal results.

Is it normal for blood pressure to vary so dramatically even in the course of an hour with no physical exertion to speak of? If I start this medication could it adversely impact me when my blood pressure readings are in the normal range much of the time? Thoughts and/or advice is greatly appreciated.