First lady Michelle Obama at River Terrace Elementary School in Washington. (AP)

It's been more than six years since Barack and Michelle Obama took up residence in the White House and inherited two of the most demanding jobs in the world. They're on my side of 50 now, a time when, like it or not, your body will begin to betray you if you don't attend to it almost fanatically. And of course you've got to throw in the whole raising-two-kids thing.

So, how are they holding up physically? Has their exercise regimen changed? On Friday I had an opportunity to talk to Cornell McClellan, the first lady's personal trainer for the past 18 years, and another member of the mid- to late-50s crowd. McClellan was circumspect about the White House workouts, as he always has been, but he did reveal a few details.

"It seems that the older we get, the more consistent we need to be," said McClellan, who flies in from Chicago several times a week to train President Obama, as well. "As they've aged in the past six years, they've gotten more consistent."

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That means the first couple get in their cardio, strength and flexibility training five or six days a week, pretty much without fail, he said. Not that the famously fit president and his wife ever slacked off.

"They...won't take two or three or four weeks off from working out," when they hit an especially busy or stressful period, McClellan said (Can you make the same claim?). "They get their workouts in. They believe it's what powers them through each and every day."

"The times [of day] might change. Sometimes you might have to split up" a workout into a couple of sessions. But it always happens, even if they have to get up earlier or stay up later. "The president and first lady believe this is a lifestyle for them."

We know that Michelle Obama has been a Solidcore fan, and that she told People Magazine when she turned 50 last year that she was planning to do less weight-bearing exercise and more flexibility work, including yoga. And that the president's workout philosophy includes "raging against death," as McClellan told TMZ just the other day.

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But specifically, what is McClellan doing as the first couple ages? "Increasing the intensity," he said. "We're going heavy, we're mixing things up...I don't believe in letting the body get too complacent." He may have them "do something explosive" before a series of squats. Or some calisthenics or plyometrics before a strength exercise. He said he likes to "pre-fatigue" some muscles before demanding a set.

"We really ask them to give us their all," he said.

McClellan is in Washington to appear at the Measure Up/Pressure Down event Saturday at the YMCA Anthony Bowen, where he will talk about the importance of battling high blood pressure.

I know, I know. All this is fine, but what you really care about is how Flotus sculpts those arms, right? I didn't forget to ask. The "real secret," McClellan said, "is consistency. And we do mix it up." That means high weight-low reps, low weight-high reps and even some high-weight-high reps sets, he said. Michelle Obama is also doing functional (full-body) exercises along with others that target her arms, he said. And she is very careful about what she eats, he said.

McClellan declined to tell me how much the first lady lifts, but he did say this: "She's much stronger than anybody would imagine, and so is the president. They're pretty strong."

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