A fitness tracker or activity tracker is an electronic device or app that measures and collects data about an individual's movements and physical responses in order to monitor and improve the individual's health, fitness, or psychological wellness over time.
Fitness trackers are a more sophisticated version of the
pedometer; in addition to counting steps, they contain additional sensors such as
accelerometer
An accelerometer is a device that measures the proper acceleration of an object. Proper acceleration is the acceleration (the rate of change (mathematics), rate of change of velocity) of the object relative to an observer who is in free fall (tha ...
s and
altimeters to collect or estimate information, including the speed and distance travelled,
heart rate
Heart rate is the frequency of the cardiac cycle, heartbeat measured by the number of contractions of the heart per minute (''beats per minute'', or bpm). The heart rate varies according to the body's Human body, physical needs, including the nee ...
, calorie expenditure, or the duration and
quality of sleep.
[Jill Duffy]
"The Best Activity Trackers for Fitness"
''PC Magazine
''PC Magazine'' (shortened as ''PCMag'') is an American computer magazine published by Ziff Davis. A print edition was published from 1982 to January 2009. Publication of online editions started in late 1994 and continues .
Overview
''PC Mag ...
'', May 22, 2013.
Improvements in computing technology since the 1980s, recently driven by the rapid advancement of
smartphones
A smartphone is a mobile phone with advanced computing capabilities. It typically has a touchscreen interface, allowing users to access a wide range of applications and services, such as web browsing, email, and social media, as well as mult ...
, paved the way for the spread of wearable tracker devices with integrated sensors. A large amount of sensitive sensor and user-input data is synced with mobile apps such as fitness, mood, sleep, water intake, medicine usage, sexual activity, menstruation, and potential illnesses. The large volume of data collected has led to privacy concerns around how consumer information is stored and analyzed by the companies involved.
History
Wearable
heart rate monitor
A heart rate monitor (HRM) is a personal monitoring device that allows one to measure/display heart rate in real time or record the heart rate for later study. It is largely used to gather heart rate data while performing various types of ph ...
s for athletes were available in 1981.
["Olympic Medical Institute Validates Polar RS800 Running Computer And Training System"](_blank)
Polar, November 7, 2006, retrieved February 25, 2014
archived
February 25, 2014. Improvements in technology in the late 20th and early 21st century made it possible to automate the recording of fitness activities, as well as to integrate monitors into more easily worn equipment. The
RS-Computer shoe was released in 1986. Early examples include wristwatch-sized
bicycle computers that monitored speed, duration, distance, etc., available at least by the early 1990s. By at least the early 2000s, wearable fitness tracking devices were available as consumer-grade electronics, including wireless heart rate monitors that could be connected to commercial-grade exercise machines in gyms.
Fitness trackers later diversified to include wristbands and armbands (so-called smart bands) and smaller devices that could be clipped wherever preferred.
[Rheana Murray]
"Smartphones become fitness coaches with new wearable activity trackers"
''New York Daily News
The ''Daily News'' is an American newspaper based in Jersey City, New Jersey. It was founded in 1919 by Joseph Medill Patterson in New York City as the ''Illustrated Daily News''. It was the first U.S. daily printed in Tabloid (newspaper format ...
'', August 16, 2013. In 2006
Apple
An apple is a round, edible fruit produced by an apple tree (''Malus'' spp.). Fruit trees of the orchard or domestic apple (''Malus domestica''), the most widely grown in the genus, are agriculture, cultivated worldwide. The tree originated ...
and
Nike released the
Nike+iPod
Nike often refers to:
* Nike, Inc., a major American producer of athletic shoes, apparel, and sports equipment
* Nike (mythology), a Greek goddess who personifies victory
Nike may also refer to:
People
* Nike (name), a surname and feminine given ...
, a sensor-equipped shoe that worked with an
iPod Nano
The iPod Nano (stylized and marketed as iPod nano) is a discontinued portable media player designed and formerly marketed by Apple Inc. The first-generation model was introduced on September 7, 2005, as a replacement for the iPod Mini, using ...
.
By 2010, logging apps had been introduced, many of which enabled the direct sharing of data to Facebook ot Twitter.
[Caroline McCarthy]
"Work out, get on scale...tell your friends?"
, CNET, July 21, 2010. Fitness trackers became appealing to consumers because of the combination of
gamification, the social dimension of sharing via
social media
Social media are interactive technologies that facilitate the Content creation, creation, information exchange, sharing and news aggregator, aggregation of Content (media), content (such as ideas, interests, and other forms of expression) amongs ...
, and increased motivation due to the resulting rivalry and competition between friends.
In 2016, there were several advances made regarding fitness tracking geared toward kids with a variety of options from organizations such as
UNICEF
UNICEF ( ), originally the United Nations International Children's Emergency Fund, officially United Nations Children's Fund since 1953, is an agency of the United Nations responsible for providing Humanitarianism, humanitarian and Development a ...
and
Garmin
Garmin Ltd. is an American multinational technology company based in Olathe, Kansas. The company designs, develops, manufactures, markets, and distributes GPS-enabled products and other navigation, communication, sensor-based, and information ...
.
Tracker formats
Most consumer fitness trackers are worn on a wristband similar to a
wristwatch
A watch is a timepiece carried or worn by a person. It is designed to maintain a consistent movement despite the motions caused by the person's activities. A wristwatch is worn around the wrist, attached by a watch strap or another type of ...
. This type of tracker usually includes a digital display for data. Wrist-based trackers may be prone to error during exercise involving rapid arm motion.
[ ]
Some fitness trackers take the form of a ring. Ring-based trackers have no display of their own and rely on a connection with a smartphone to display tracked data.
Another low-profile format for fitness trackers places sensors inside of
earphones
Headphones are a pair of small loudspeaker drivers worn on or around the head over a user's ears. They are electroacoustic transducers, which convert an electrical signal to a corresponding sound. Headphones let a single user listen to an ...
. These trackers rely on a smartphone to display data, similar to ring-based trackers. Earphone-based fitness trackers use sensors to take readings directly from the
capillaries
A capillary is a small blood vessel, from 5 to 10 micrometres in diameter, and is part of the microcirculation system. Capillaries are microvessels and the smallest blood vessels in the body. They are composed of only the tunica intima (the in ...
located within the ear. Due to their placement, these trackers can give more accurate results for blood pressure,
electrocardiogram, and body temperature. Fitness trackers placed in the ear are also well suited to the assessment of heart rate.
Activity tracking on smartwatches

Many devices primarily intended as
smartwatches also function as fitness trackers.
An early example was the
Apple Watch
The Apple Watch is a brand of smartwatch products developed and marketed by Apple Inc., Apple. It incorporates activity tracker, fitness tracking, Health (Apple), health-oriented capabilities, and wireless telecommunication, and integrates wit ...
, which has offered fitness tracker functions since 2014.
Tracker apps
The standard activity-tracking smartphone or web apps present data in statistical form meant to be viewed after the activity has ended. However, research suggests that if we want a richer understanding of the data, we need intelligent computing to be included in the systems that run the apps.
Performance problems
Certain movements of the user can distort the results obtained from fitness trackers as seen in a test conducted by
Stiftung Warentest where the products were unable to accurately track a bike ride.
[Fitnessarmbaender - Nur zwei von zwoelf sind gut](_blank)
test.de, November 23, 2023. Furthermore, the determined values for the human
energy transformation
Energy transformation, also known as energy conversion, is the process of changing energy from one form to another. In physics, energy is a quantity that provides the capacity to perform work (e.g. lifting an object) or provides heat. In addit ...
were erroneous.
With the heart rate large deviations have been observed at wristlet trackers, and it is recommended for this purpose to use appropriate chest straps.
Wristbands can be uncomfortable to wear and inadvertently be lost. For some products,
genotoxic substances were detected.
Privacy concerns
There have been some privacy issues regarding the data collection of activity-tracking apps, a user's health can be tracked into a "digital health footprint". There have been many concerns about privacy issues with menstruation and reproductive health-tracking apps.
Many women who use these apps for menstrual and contraceptive tracking are under the impression that their data is private when there is no single body regulating the apps, making the availability and protection of the data unknown.
The apps of some fitness trackers not only transmit personal data but also private address lists to servers on the Internet without notifying or asking the user.
Even when anonymized, the mere presence of geolocation data may be a national security risk. However, the results of a study among semi-professional (half-)
marathon
The marathon is a long-distance foot race with a distance of kilometres ( 26 mi 385 yd), usually run as a road race, but the distance can be covered on trail routes. The marathon can be completed by running or with a run/walk strategy. There ...
participants suggest that certain users are open to sharing tracked activity data voluntarily.
In the US in 2013,
BodyMedia developed a disposable fitness tracker to be worn for a week, which is aimed at medical and insurance providers and employers seeking to measure employees' fitness. In 2014, Jawbone developed a system called UP for Groups which could provide employers with aggregated data from employees' wearable fitness trackers and apps.
Psychological impacts
Research has been carried out on the gamification of health apps, where users earn incentives and rewards based on their health goals.
Though this can make the app engaging, there was concern it could trivialize health apps and deter the users from their genuine health goals.
There is also research problematizing tracking devices about how we inhabit, experience, and imagine our bodies and lives.
Wearable sensors
Wearable sensors have been widely used in medical sciences, sports, and security. Wearable sensors can detect abnormal and unforeseen situations, and monitor
physiological
Physiology (; ) is the science, scientific study of function (biology), functions and mechanism (biology), mechanisms in a life, living system. As a branches of science, subdiscipline of biology, physiology focuses on how organisms, organ syst ...
parameters and symptoms through these trackers. This technology has transformed healthcare by allowing continuous monitoring of patients without hospitalization.
Medical monitoring of a patient's body temperature, heart rate, heart rate variability,
brain activity, muscle motion, and other critical data can be delivered through these trackers.
Moreover, in
sports training, there is an increasing demand for wearable sensors. For example, measurement of sweat rate was possible only in laboratory-based systems a few years ago but is now possible using wearable sensors. Heart rate variability (HRV) has the potential to determine the quality of an exercise regimen. Additionally, HRV is recommended among the athletic community as a warning sign for over-training. In these ways, HRV can be used to optimize performance.
Medical uses
Fitness trackers are not medical devices. However, newer models approach the US definition of a
Class II medical monitor, and some manufacturers hope to eventually make them capable of alerting to a medical problem, although
FDA approval would be required.
[Dan Holden, "Worn Out: The Dark Side of Wearable Technology", '']Metro Silicon Valley
''Metro'', also known as ''Metro Silicon Valley'', is a free weekly newspaper published by the San Jose, California-based Weeklys media group for four decades, a period during which its readership area became known as Silicon Valley.
Metro was ...
'', September 24, 2014, pp. 16–18.
Detection of atrial fibrillation
Activity tracking has been utilized to keep track of
atrial fibrillation
Atrial fibrillation (AF, AFib or A-fib) is an Heart arrhythmia, abnormal heart rhythm (arrhythmia) characterized by fibrillation, rapid and irregular beating of the Atrium (heart), atrial chambers of the heart. It often begins as short periods ...
(AF), an irregular and chaotic heartbeat, which is accountable for a majority of strokes in the United States.
Professionals rely on the ambulatory electrocardiogram (EKG) to record AF but soon found wearable wristbands to be useful for regular usage.
These wearables must be accurate to prevent misdiagnosis, morbidity, and mortality.
The Apple Watch was found in a study to be able to detect and notify the wearer of an irregular pulse.
Though there is a risk of false positives, the study found that it may be a useful tool in the initial diagnosis process as a gateway to additional procedures rather than being the only tool used.
Weight loss and obesity
Fitness trackers have also been used for tracking and finding solutions to combat obesity by promoting physical activity.
A device called the Fitbit Alta was used as the wristband for adolescents who are considered obese where their steps, distance, calories burned, activity time, and sleep rates were kept track of and downloaded by the researchers to analyze.
The overall study found that societal and cultural factors were what affected adolescent obesity given that low-income minorities were at a higher risk given that they had limited access to weight management programs and resources.
The tracking of steps and amount of physical activity allowed for one to be aware of their habits and lifestyle, but the access to weight loss programs varied for many, which is why the researchers utilized this information and used the technology to correlate behavioral aspects with the data to search for more solutions.
One review of six studies found that there was little evidence that fitness trackers improve health outcomes.
Of five studies that looked at weight loss, one found benefit, one found harm, and three found no effect.
Another systematic review covering 35 studies and 7454 participants, published in the British Journal of Sports Medicine, found that fitness trackers increased people's physical activity by an average of 1850 steps/day.
According to another study comparing 8-week interventions and four-month follow-ups of physical activity monitors, a guided weight loss program, and together, activity monitoring and the weight loss program are associated with similar improvements and both combined are associated with more improvements than either alone.
It is unclear whether activity changes occur in children and adolescents.
Monitoring stress and mental illness
There are many apps available in the Apple AppStore and the Samsung Google Play Store that deal with mental health management and self-help. Smartwatches have also been involved in monitoring stress and other mental health issues.
A study was done analyzing the different types of devices, ranging from bulky wearables to smaller, portable devices with sensors that can detect depression, anxiety, and any form of stress.
Monitoring these main three factors is essential to understanding any risk and likelihood of additional health complications and the correlation to specific conditions.
Chest patches are used for measuring heart rate while the wristbands ("Chillbands") were used to track activity, where a correlation was seen in the HR levels and the involvement of circadian rhythm, stress, gender, and age.
It was seen that detecting depression alone was challenging, causing a risk of misdiagnosis, but further research along with tracking of sleep, physical activity, mood changes, cognitive function, and social habits will help towards accurate measurements.
Monitoring infant growth development
Wearable sensors have also been in use when keeping track of infant development, motor skills, and physical growth are the main aspects that were focused on.
Parkinson's disease prediction
Physical movement tracking can be used as a predictive analysis tool to determine the risk of Parkinson's Disease in individuals.
Alerting for caregivers
Other fitness trackers are intended to monitor vital signs in the elderly, epileptics, and people with sleep disorders and alert a caregiver to a problem.
Menstrual tracking and reproductive health
Individuals with a uterus can use menstrual tracking apps to keep track of their cycles and refer back to the timeline to spot any changes that they would like to bring up to their doctors or specialists.
There are several apps for this purpose but the privacy and security of the data are unknown given that there is no one "head" that oversees the system, leaving a lot of the data open to the market, leaving many questions as to how secure the data is when entered.
When users sign up for these apps, they are usually led with an "at your own risk" warning in case any data gets leaked, which can contribute to more targeted ads and inaccurate predictions in their cycles.
Animal health
Fitness trackers have been designed for animals, for example collar-mounted fitness trackers for dogs.
[Heather Zimmerman, "Digital Dog", ''Metro Silicon Valley'', September 24, 2014, p. 17.]
See also
*
Sleep tracking
*
Actigraphy
*
eHealth
*
Internet of Things
Internet of things (IoT) describes devices with sensors, processing ability, software and other technologies that connect and exchange data with other devices and systems over the Internet or other communication networks. The IoT encompasse ...
*
Quantified self, movement to record, analyze, and improve one's daily life
*
Smartwatch
A smartwatch is a portable wearable computer that resembles a wristwatch. Most modern smartwatches are operated via a touchscreen, and rely on mobile apps that run on a connected device (such as a smartphone) in order to provide core functions. ...
*
Wearable computer
A wearable computer, also known as a body-borne computer, is a computing device worn on the body. The definition of 'wearable computer' may be narrow or broad, extending to smartphones or even ordinary wristwatches.
Wearables may be for general ...
References
Further reading
* Robert Scoble, Shel Israel. ''Age of Context: Mobile, Sensors, Data and the Future of Privacy''. Patrick Brewster, 2014. .
{{Authority control
Internet of things
Smart bands
Sports nutrition