Those blood pressure values aren't consistent, they tend to go up and down - but have trended high over the last couple of years.
Normally my diet is very low in salt, however, the night before the recent test with the 159/96 result, I had a high salt meal late and very little fluid. I'm also not a big water drinker on a daily basis.
I'm 45 with no other medical conditions that I'm aware of.
Garrett - thanks for the info, I have annual blood tests to check for liver function so hopefully the results will continue to be ok.