Fitbit Flex: How A Bracelet Can Help You Get Lean

Share on Facebook43Tweet about this on Twitter7Pin on Pinterest1Email this to someone

fitbit-flex-get-leanUpdate, 2/20/15: After a year and a half of daily use, my Fitbit tracker stopped holding its charge. I contacted Fitbit support and was promptly sent a new Fitbit Flex that arrived in three days. Big thanks to the great folks in customer service for taking care of me!

I’m a big believer in nonexercise activity thermogenesis, or NEAT, for staying active and losing body fat. As my NEAT article indicated, low-intensity activity, such as comfortable walking, requires almost three times as many calories as sitting, and the majority of those calories come from body fat.

Although exercise plays an important role in limiting body fat, for a variety of reasons, traditional cardio is perhaps the least desirable strategy for getting lean.

I prefer walking. It requires no special equipment, it’s easy on the body, and it’s enjoyable. It can also be done anywhere: shopping, hiking, errands, or the park. Even work environments provide many opportunities to walk. You can take the stairs, schedule walking meetings, or use a treadmill desk.

The only limitation of walking for fat loss is it’s a very slow process. Walking won’t do much for you in a week or two, but getting out of your work chair and moving another 2 to 3 hours a day can result in a dramatic fat loss of 20 to 30 kg a year (about 44 to 66 pounds).

So what’s the best way to monitor low-intensity activity like walking?

Pedometers are great in theory, but it’s easy to forget to clip them to clothing every day. The visibility of the device (“Oh, you’re wearing a pedometer!”) is also something I can do without. The 24/7 option, the Fitbit Flex, eliminates these problems and offers a number of additional cool features. For me, there are five benefits of the Fitbit Flex.


  • You wear a rubber bracelet with a removable sensor that can track the number of steps you take in a day
  • The bracelet can be worn in the shower or in the rain (but not underwater because of the pressure)
  • You can sync the data to your PC or Mac, which allows you to view steps taken, calories burned, and distance traveled
  • The device is Bluetooth enabled, so you can use a newer smart phone (like the iPhone 4S or 5 and Samsung Galaxy S III or S4) ┬áto sync data and monitor your progress with the Fitbit app
  • The FF can also be used to track sleep duration and disruptions, which is useful if you want to examine the link between sleep quality and daily activity

Last weekend I picked up a $99 Fitbit Flex (which I’ll refer to as FF) to help me track just how NEAT my days are. As you can see in the photo above, the bracelet is low profile. It can be a minor challenge to line up the buttons on the clasp to put it on the first time, but once it’s on, it stays on. Ideally you’ll have it on for five days before it’s time to recharge the tracker. The bracelet is so comfortable to wear, it’s easy to forget that it’s on.

Setup is a breeze. The package includes no instruction manual other than an insert that instructs the user to log on to the Fitbit website to set up an account and download the software. The process is super easy. New users will be up and running in minutes. After you plug your wireless USB device in your computer, the tracking device in the bracelet will periodically upload your data to the Fitbit site when you’re near your computer. You can also sync your data through your smart phone, which I’ll address later.

The walking data appear to be quite accurate. I was concerned that random arm movements would result in erroneous tracking, but that doesn’t seem to be an issue. Typing, bouncing toys in front of my cat, and washing dishes had no impact on the estimated number of steps. To avoid false positives, the FF instructions suggest wearing the bracelet on the non-dominant wrist, but there is a software setting to account for excessive movement if the bracelet is worn on the dominant wrist.

I was curious about how the FF would respond to activities other than walking or running. To evaluate, I got on my bike. I picked up this cruiser a few weeks ago. Coaster brakes, no gears, lots of fun.


I’ve been taking advantage of every opportunity to ride my new toy, so I took it for a fast ride several hours after picking up the FF. Unfortunately, my (approximately) 1700 pre-ride steps increased by about 3000 after going for a ride, which means the sensor detects cycling as steps. As you can see below, the FF describes my cycling time as 33 “very active” minutes.

FF Dash

I was also amused to see that, according the FF Flex, I’m a “Champ!” for my 33 very active minutes of exercise. I’ll take it.

The good news is, if you’re concerned about how your other activity might impact your step counts, you can make the appropriate modifications on the FF website. I don’t mind including bike time in the total, but others may wish to be more precise.

As you can see by looking at the dashboard data, calories burned (based on height, weight, age, activity level, and estimated basal metabolic rate) and distance traveled are provided.

From the FF dashboard, you can also log food eaten, weight, and health indicators like heart rate. And if you wish, you can monitor the activity of your friends who use the FF, which is a solid feature for people who like a dose of camaraderie with their exercise.

Although I don’t see myself using the FF tools to log these data, I was pleased to see that the FF can sync with fitness apps and websites (like SparkPeople, Endomondo, and many others) that you may prefer to use to track your diet and exercise behavior. I use MyFitnessPal occasionally to track my diet, so I was excited to see the integration of applications here.

The sleep tracking feature is fascinating. In the image below, you can see I set the FF to monitor my sleeping when I went to bed at 2:38 AM (too late!) and it took 6 minutes to actually fall asleep. I started moving a bit around 5:00 (close to my usual wake-up time), then 6:00, and finally just before 7:00. At that point, I was up for good. I got a little over 4 hours sleep. I know, that’s terrible. Don’t hate. I’ll sleep more tonight. The feedback is valuable and sleep matters, so I plan to get a lot of use out of this feature.

FF sleep

Here’s a screenshot of the Android app:

FF App

As I mentioned before the Android app syncs through Bluetooth, so you don’t have to rely on being by your computer to sync your data. From what I can tell, the app provides the same information as the website’s dashboard, so it’s easy to monitor your progress throughout the day. My only gripe about the app is that the Bluetooth syncing is slower than I expected, but this is a very minor complaint that will only impact the impatient. In addition, if left on all the time, Bluetooth can drain the battery quickly. But this is also minor; it’s easy enough to turn off Bluetooth until you have the desire to sync again.

Overall, I love the Fitbit Flex. It’s accurate, low profile, easy to sync, data rich, compatible with many diet and exercise apps, and the battery lasts and lasts. For $99, it’s a great value. I look forward to using it to track my NEAT activity every day.

Share on Facebook43Tweet about this on Twitter7Pin on Pinterest1Email this to someone

Join Over 10,000 Monthly Readers

Subscribe to my newsletter and follow me on Facebook!

  • Anonymous

    I’m not a gadget girl, and this review made me want the Fitbit Flex. I plan to pick one up today. Thanks for the great review, Joel!

  • Joel Minden

    Thanks for the feedback! I hope you enjoy the Fitbit Flex like I do!

  • Maria Clarys

    I purchased my Fitbit Flex 4 days ago. I love it so far, but am not entirely sure that the pedometer function is accurate. I am pretty active…lots of walking in a day, plus dog walks, etc. But I seem to hit the 10,000 step mark by around early evening, even on my moderate or slow days. (spent about 5 hours in the car today, and it still registered that I hit my goal.) I will be watching to see if anyone else has feedback, and will go to the website to see if I can manipulate the data to better reflect my activity type. Thanks so much for your great review and experience!

    • joelminden

      Maria, I’ve heard reports from other folks about problems with driving/step counts but I haven’t experienced this. I believe there’s a way to account for the time you spend driving, playing a sport, etc. in the FitBit dashboard. Hopefully you found some settings to adjust to improve the accuracy of the device.

  • Pingback: This Week in Food, Health, and Fitness | Sheila Kealey()

  • FitnessForesight

    Really great article the flex is a great product from fitbit. We have just tested out the charge hr. If you would like to learn more about what it can do be sure to check out and to see where you can buy for the best price