Mitt Romney's running mate, Paul Ryan, claimed he'd finished a marathon in the "high twos." Hours, that is. That put him in an ultra-elite running club with Canada's Brendan Lunty, who finished the 2013 New York City marathon in 2:36:17 and America's Ryan Vail who crossed that finish line in 2:13:23 (top finishers that year for those countries).

Unfortunately, Ryan vastly overestimated his performance and underestimated his time; 20 years earlier he'd completed a marathon in over four hours. But, even if you're skeptical about any politician's ability to tell the truth, the fact is people typically overestimate how intensely they're exercising.

In a recent study, folks walked or jogged on a treadmill and then were asked if they'd achieved levels of moderate and vigorous exercise. Moderate activity allows you to talk comfortably, but not sing; vigorous activity only allows you to say a few words without pausing for a breath. Three-quarters of folks thought they were putting out moderate effort, but fell far short of it. Folks overestimated vigorous output, too.

To make sure you're getting an effective workout, talk with your doc about establishing a daily walking routine (aiming for 10,000 steps a day) that you then amp up. The drill: Two to three times a week, warm up for five minutes; walk at your regular pace for one minute; walk as fast as you can for 20-30 seconds; then go back to your regular pace for another minute. Repeat that cycle for 20 minutes. Now, that's truly something to brag about!