Do fitness monitors really help you improve your fitness?

Every week, Lisa Setterlund engages in a fierce battle with her co-workers to see who's the most active.

The White Bear Lake runner tracks her daily steps on her trusty Fitbit Flex, a wristband she dutifully wears around the clock. She keeps tabs on both her own movement and that of her colleagues — adding more steps to her daily routine, as needed.

"It's been fun," she said of the weekly contests. "We'll figure out how close we are together and people start walking around."

The monitor makes her more accountable, she said. "If I'm checking it, and I know my goal is 10,000 [steps a day], it will force me to get up if I'm at 8,000," she said.

Setterlund and her Rasmussen College co-workers are among legions of health-conscious people who wear some kind of activity tracker. And while the arrival of smartwatches with health tracking features is giving traditional devices some serious competition, the wristbands and belt clips remain popular.

But can they really make us healthier?

Those who like numbers and don't need a kick in the pants seem to get the most out of their trackers, according to Mark Blegen, associate professor of exercise science at St. Catherine University in St. Paul.

"What's being shown about them is that they work for a segment of the population that's already motivated," he said. "If I'm competitive and I really like exercising and data, then it works."

But a gadget that tracks steps and calories burned and even sleep cycles is no substitute for long-term motivation, Blegen argued.

"People think this is really what's going to get me off the couch. It will for a few people and for a little while, but it doesn't address the underlying issue," he said.

Those who want to get more fit would do better to figure out why they aren't exercising in the first place — whether it's lack of time, child care issues or whatnot — and find ways to eliminate those barriers instead.

"Whether it's a Fitbit or the Apple Watch or now we're getting into the wearable [technology] clothing, it's still in its infancy," Blegen said. "Right now, I'd say try to address the barriers you have to exercising. Doing simple things like putting your tennis shoes in your gym bag by the door or scheduling a workout time will be more powerful than tracking fitness.

"It's not sexy. We like the shiny object. I can go buy this Fitbit and guess that it's going to change my life totally. For some small segment of the population it might, but it's the daily habits that are much more powerful than tracking things."

Marc Schober was already a regular exerciser when he got his Fitbit Charge HR for Christmas. But wearing his daily steps on his sleeve has made him even more mindful of his health, he said.

"It's completely changed my mind-set," said Schober, of Vadnais Heights.

Before, he measured his fitness by the number of days he worked out at the gym. "Now my Fitbit helps me understand how healthy I truly was and it doesn't necessarily involve the gym," Schober said. "If, at lunch, I walk through the skyways three miles, that's a healthy day. This gives me the knowledge of just how active I really am."

Armed with that knowledge, he has walked more at lunchtime since he started wearing a tracker.

But that leads to another very big question: How do we know if the numbers spit out by fitness monitors are accurate? What if we're basing our fitness decisions on bad information?

Some wrist devices have been known to count pushing a child on a swing or knitting as steps, but other activities — such as ice hockey — don't register as much movement.

Earlier this year, three people filed a class-action lawsuit against Fitbit, alleging that the company's PurePulse Trackers gave inaccurate readings for their heart rates. One of the people claimed that her tracker recorded her heart rate at 82 beats per minute, but a follow-up check by a personal trainer came up with 160 beats per minute, the suit said.

In a statement, Fitbit officials disputed the allegations, saying: "Fitbit stands behind our heart rate technology and strongly disagrees with the statements made in the complaint and plans to vigorously defend the lawsuit."

Schober said he trusts his tracker, even though he knows it's not perfect all the time.

"I don't think it's 100 percent accurate, but it's more accurate than what I anticipated," he said. He sometimes compares the readings with those displayed on the machines he uses at the gym.

As for Setterlund, she's not bothered by the accuracy questions.

"That's what's funny. I don't know if it is [right] or not," she said. "It's just for me, so it doesn't matter if it's incredibly accurate."

Accuracy aside, all this tracking can actually sabotage your motivation to move more, Blegen warned.

"It has the potential of working the other way — of being a reminder that you're not as active as someone wants you to be," he said. "If I'm constantly reminded that I'm not doing a good enough job, pretty soon I'm not going to even try."

Studies show that 40 percent of activity tracker users stop using the devices within six months.

Sometimes called "Fitbit fatigue," it's a phenomenon that Blegen has seen at his own workplace, where enthusiastic co-workers new to the tracking game proudly show off their devices when they get them but then lose interest in them.

"At St. Kate's for a while they were popping up all over the place, but within a couple months they fade away," Blegen said. "They get really excited for a while and say, 'Look, Mark, what I've got.' Invariably, a few months later you don't hear that conversation anymore."

Though it's only been two months since Schober started wearing his tracker, he said he hasn't felt the least bit fatigued by all the data and feedback from his device.

He has set a personal goal to walk 11,000 steps a day — the equivalent of six miles. He also aims to climb 15 flights of stairs. Sometimes, when his tracker shows that he's a little short of his goal at day's end, he springs into action.

"I'll find myself quickly running up the stairs a couple times before going to bed to meet my goal," Schober said.

Allie Shah • 612-673-4488