Higher BP caused by age related blood thickening?

After reading numerous forums on hypertension/blood pressure, it seems interesting how many people had their blood pressure shoot up on them that are in the 48-50 yo age group. Mine also decided to go through the roof last year at 49.

I read somewhere that as we age our blood naturally gets thicker, and this causes more work for the heart and more pressure on arteries as the thicker blood is forced through them. This would really explain the typical onset of HBP in middle age which I've heard explained otherwise. It would also explain why taking a blood thinner like asperin every day wards off heart attacks and strokes as you get older and at greater risk.

Has anyone heard this before, or have any idea whether its true or not?