At Arlington National Cemetery, the changing of the guard happens like clockwork.

Since 1937, regardless of weather or world events, it's taken place every 30 minutes from 8 a.m. to 7 p.m., April 1 through September 30; every 60 minutes October 1 through March 31; and every two hours when the cemetery is closed.

Heart patients should take note, suggest researchers from the University of Alberta at a recent Canadian Cardiovascular Congress. Many people with heart disease spend most of their waking hours sitting or lying down, often and watching TV.

They need to change that up with an iron-clad schedule of seven minutes of light activity, such as walking, every 20 minutes. That way they'll burn around 770 extra calories a day, help circulation, reduce inflammation, and raise their spirits.

But sometimes, more than lifestyle intervention is needed. Sometimes we have to make a midcourse correction.

It's time to change how you guard your heart health by taking charge of your well-being (get that pedometer and timer) and working with your doctor on medical interventions, be it antihypertensives, statins, aspirin, or diabetes meds.

That'll give you big rewards. So move it and use it, or lose it.