Blood Pressure Question?

My blood pressure is 135/66 right now with heart rate of 80. What could account for the large discrepancy in the numbers of the actual blood pressure? i work out 5-6 times a week, im 6'8 240 with around 10% body fat. I dont usually take my blood pressure but its always in the high range on the top end but i dont know why the other number would be so low in comparison?