Systolic blood pressure is the top number in a reading. It's the pressure exerted at the beginning of the hearts pumping cycle. Diastolic, the bottom number, measures the heart's resting cycle.
Researchers say as the population ages a rise in systolic pressure is resulting in what's called systolic hypertension. That's why they believe using a systolic blood pressure after 50 would simplify treatments for doctors and get patients to focus on a single number and realize that number needs to be lowered.