I think it was because I put on 15kg of mass in 12 weeks, so my heart had to deal with the extra body mass maybe, since it was a fast gain.
Also, was drinking 3L of full fat milk at the time, eating anything at all, losts of saturated fats, and hadn't done any cardio in 2 years.
After I found out it was that high, I changed my diet for a week and did cardio almost daily and it went back down immediately.
It was high for about a week before I made this change.
Went to the doctor and he gave me medication, only took it for 2 days though as I didn't want side effects.
When I went back a week later to get checked again, and told him I didn't take the pills, he was pissed and telling me I don't know what I'm doing and he had to study 8 years to get where he is, and gave me a big lecture.
Then he checked my pressure and it was normal, so then he just shut up and agreed that I didn't have to take the pills.
Since then, I've been pretty stable.
Just use light milk now and do cardio once in a while, but not regularly.
If it ever gets high again, I'll just throw some cardio in, seems to be the solution for me.