Is Low Blood Pressure Ever Too Low? What's Normal Blood Pressure? What's High?

Q. How low is too low for the bottom blood pressure number and how high is too high for the top one? My dad's numbers have been shifting somewhat. I'm calling his doc tomorrow for an appointment to see what's going on, but what's so high or low that I should take him to the emergency room?
-- Teresa, via e-mail

A. We get asked about high and low blood pressure numbers more often than Sarah Jessica Parker gets asked if she's wearing Manolos. (Our wives told us about that.) What's too high for the top number (systolic) is simple: Anything above 160 is an emergency -- head for the ER immediately.

What's too low for the bottom number (diastolic) varies. It measures the pressure in the arteries when your heart muscle relaxes between pumps, so you want it to be low. For diastolic, the normal blood pressure range is 60 to 80, but lower is better. Generally speaking, if your dad can easily stand up and talk to you, it's not too low. Still, since both his systolic and diastolic numbers are moving, you're smart to get his doc involved. This guide will help you, your dad, and his doc talk things through.

You don't mention your dad's age but we're guessing he's in his 60s or 70s. Blood pressure tends to creep up around 65 but the American Heart Association's recommendation doesn't: Stay under 120/80. We're even more aggressive: We like BP (not just your dad’s; yours too) to be as low as you can get it without tumbling over. Under 120/80 is good; 115/76 is optimal. People in that range have half as many heart attacks and strokes. Dr. Mike's numbers are 115/75; Dr. Oz stays around 110/75. Go for optimal!

How? Eat well -- lots of fruits, veggies, and 100% whole grains, and next to no saturated/trans fats and added sugars/syrups. Walk 30 minutes a day, every day. Sleep 8 hours a night, every night. (Not getting enough sleep can sharply increase blood pressure.) Manage stress. If your dad needs blood pressure meds (sounds likely), make sure he takes them as if his life depends on it. It does. There are other huge benefits from taking blood pressure drugs, too.

When your dad -- or you -- can almost feel your blood pressure rising, do this.