Computer Science


The term Fitbit refers to activity tracker devices manufactured and sold by Fitbit Incorporated. Designed to help users take control of their health and fitness, Fitbit devices track data such as step counts and calories burned, among other functions. Following their introduction to the market in 2009, Fitbit devices popularized wearable activity trackers among the public, prompting the creation of a wide variety of competing fitness devices.



In the first decade of the twenty-first century, growing interest in health and fitness converged with significant advances in consumer technology. This lead to the increasing popularity of wearable electronic devices. The personal activity tracker is essentially an upgraded version of earlier pedometers (step counters). Activity trackers record and measure fitness data. Newer models can sync seamlessly with the user's computer or smartphone. One such family of devices, sold under the brand name Fitbit, was introduced in 2009. Different Fitbit products allow users to track various fitness-related data.

Fitbit Incorporated was founded in 2007 by James Park and Eric Friedman as Healthy Metrics Research Incorporated. The company's initial goal was to incorporate accelerometers into wearable technology. Accelerometers are small sensors that measure acceleration forces. The founders presented a prototype consisting of a circuit board within a small balsawood box to investors in 2008. The company's first device, known as the Fitbit Tracker, was released to the public in 2009. The original Fitbit clipped to the wearer's clothing. The small device could count and track the number of steps taken and estimate released numerous additional Fitbit devices featuring different functions.


The Fitbit Tracker could track the number of steps the user took per day and estimate how many calories such activity burned. The device also tracked the user's sleep duration and quality. The Fitbit Tracker could be worn clipped to the user's clothing during the day. It also came with a wristband with which to wear the device at night. The device was paired with a website where users could document their exercise routines and meals and record their weight. It also came with a charging station that enabled users to wirelessly upload the data collected by their Fitbits.

Over the following years, Fitbit introduced more than ten other devices with a variety of different functions. Its products are divided among three product lines: everyday, active, and performance fitness. Devices such as the Fitbit One and the Fitbit Charge belong to the everyday fitness category. They track the user's minutes of activity and number of floors climbed, among other data. Some devices, including the Fitbit Charge and the Fitbit Alta, feature clock displays and can connect to the user's smartphone to display caller information. The active fitness product category includes the Fitbit Charge HR and Blaze. The Charge HR adds heart rate tracking to the Fitbit Charge's features. The Fitbit Blaze features the standard activity-tracking features as well as music controls and phone notifications. The Fitbit Surge, a performance fitness device, can track the user's location via GPS, among other features. Fitbit also manufactures the Aria smart scale. Aria tracks the user's weight, body mass index, and other data and syncs with both the user's activity tracker and the Fitbit website.

Activity trackers include a number of sensors and outputs that allow users to monitor health-related data such as steps taken, heart rate, sleeping patterns, and more. EBSCO illustration.

Activity trackers include a number of sensors and outputs that allow users to monitor health-related data such as steps taken, heart rate, sleeping patterns, and more.
EBSCO illustration.

As multifunctional wearable devices, Fitbit activity trackers require that numerous components fit into a limited amount of space. The Fitbit Flex wristband-style device, for example, contains a variety of small electronic components, including several integrated circuits (ICs). An IC is a silicon microchip that can perform a specialized task, such as handling memory. One core component of the Fitbit Flex is the three-axis accelerometer IC, which measures acceleration forces to track the user's movement. The device also contains a printed circuit board (PCB). The PCB houses and connects multiple smaller components. It is controlled by a microcontroller, a chip that is essentially a tiny computer, complete with memory and a processor. As the device has a vibrating silent alarm function, the Fitbit Flex likewise has a vibrator component. For connectivity purposes, the device contains a low-energy connectivity IC, which enables wireless Bluetooth connectivity. It also has a near-field communications (NFC) antenna. The NFC antenna enables the device to communicate wirelessly with other NFC-compatible devices such as certain smartphones.

The specific components used in a Fitbit product vary based on the device in question. For example, the Fitbit Surge differs greatly from the clip- or wristband-based devices in terms of composition. However, the components in use generally have a number of common characteristics, including small size and very low power usage.


The popularity of the early Fitbit devices spurred other companies' efforts to create similar devices. Some of these companies had been working on activity trackers prior to the advent of Fitbit. Some other activity-tracking wearable devices include Nike+ products, Jawbone UP bands, and the Apple Watch, which has some activity-tracking capabilities.

However, this popularity has also raised concerns regarding user privacy. The activity data gathered by such devices, and particularly GPS data, could potentially be used for harm if accessed by individuals with malicious intent. The safety and accuracy of Fitbit devices have also been called into question. A 2014 class-action lawsuit alleged that the Fitbit Force's wristband caused users to develop rashes on their wrists. Another lawsuit filed in January 2016 argued that the company had misled consumers about the accuracy of the heart rate data gathered by the Fitbit Surge and Fitbit Charge HR.

—Joy Crelin

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