Wearable Devices
Smart Wearable are no more designed just for fashion. Modern day accessories come with a range of devices that brings technology into day to day trends. Blending lifestyle accessories with technology gives you access to day to day health vitals, reminders for important tasks and yes, you don’t have to pick out your pocket gadget for important messages or music, all accessible with minimalistic wearable accessories.
Smart watches and fitness trackers are increasingly becoming part of modern day lifestyle. Monitoring essential health vitals like blood pressure, heart rate, sleep pattern, calorie expenditure and physical movements on one hand has contributed to improved healthy lifestyle, bringing difference between two gadgets blurrier day by day. These smart wearables have been actively contributing to health management, detecting certain heart diseases and movement disorders quite early.
How does Smart Watch and Fitness tracker work?
Fitness Tracker
Fitness tracker can be categorised as the slim version for Smart Watch. Fitness tracker with all the sensors continuously captures data packet of health vitals, which is displayed on the slim screen. Sensors like gyroscopes, accelerometers, and PPG sensors continuously transmit data packets back to platform of health management. Which thereby does the logical evaluation and transmits alert based on algorithm in case of any alarming scenario. This data is stored in the device in case of fitness tracker.
Smart Watch
Smart watches much like fitness tracker, has a enhanced functionality, of monitoring health vitals along with Functionality of mobile phones like music, calling, mail notification etc. where data is stored in an app which in the phone, which is usually paired with Smart Watches. This data is stored on cloud servers accessible for evaluation. These devices capture basic Body Mass Index (BMI) data while pairing up, which can be used to co-relate various trends to capture early trends of disease.
What is the difference between Smart watches and fitness tracker?
Fitness tracker
Fitness tracker serves the basic purpose of capturing health parameters through sensors. They have a slim display and continuously monitor health data. These devices measure blood pressure, heart rate, calorie burning, footsteps counting, stress monitoring and sleep pattern. These devices usually have Global Positioning System (GPS) and all the basic sensors like gyroscopes, accelerometers, and Photoplethysmography (PPG).
Smart Watches
These devices in addition to basic fitness tracker function also serves the purpose of mobile phones. Reading out notifications, text , basic calling etc. Smart watches also come with all basic sensors like gyroscopes, accelerometers, and PPG , that capture vitals. Smart watches are generally paired with an app in mobile phones.
What all Health Parameters does Smart Wearable track ?
All smart wearables consists of sensors which enable them to track following basic health vitals:
- Blood Pressure
- Heart Rate
- Calorie Expenditure
- Step Counting
- Body Temperature
- Pulse Rate
How Fitness tracker / smart watches track heart rate ?
These devices have PPG sensors that monitors the heart rate. Red / Green light in device on the wrists measure changes in blood volume. This generates PPG waveform that determines individual heart rate. This data can be correlated with various other parameters related to Body Mass Index (BMI) to track stress, heart rate variability etc.
How Fitness tracker / smart watches track foot steps?
Fitness tracker / Smart watches have accelerometer sensor. These 3-Axis accelerometer measures motion, deviation, movement in all direction to track movement or running pattern. As these smart wearables are usually worn on wrist, chances of error in reporting is high. Most desirable device to track movement foot steps can be ankle sensors which is much more accurate.
How Fitness tracker / smart watches track blood pressure
Fitness Tracker / Smart watches track blood pressure throuh PPG sensors. These sensors measure the Pulse Transit Time (PTT) to evaluate blood pressure. This refers to the difference within oxygenated blood and deoxygenated blood vessels carried through arteries.
How do fitness trackers measure calories?
Smart wearable devices measure calories expenditure while monitoring the heart reate. Heart rate is measured with PPG sensors. With information wrt to BMI already fed into the device, calculating count of calorie expenditure is done.
How Fitness tracker / smart watches track sleep pattern?
How do fitness bands track my sleep? How do they sense the light sleep and deep sleep?
Smart watches / Fitness trackers are able to approximate the sleep patterns with Actigraphy – tracking movements during sleep to realise sleep pattern. These trackers monitor hand movements through gyroscopes and accelerometer. The variability in hand or body movement helps devices to identity the stage of sleep, whether it is stage 1 / stage 2 or REM sleep stage. Actigraphy along with Heart rate variability, helps to determine the sleep stage. However, data accuracy of sleep stage is not that accurate as, there can be error while recording hand / body movements.
How Fitness tracker / smart watches track stress?
Fitness tracker / Smart watches measures stress while measuring heart rate variability (HRV) through PPG sensors. HRV data along with body temperature, sweat levels score the stress level. This data is read correspondingly with sleep data to identify the stress category or stress score.
Side Effects of Wearable Technologies
Wearable Technologies has penetrated to our daily lifestyle to an extent that its role complementing our healthy management cannot be neglected. Studies is being carried out to analyse and minimise the extent of side effects of wearable technologies. Although side effects of wearable is yet to be documented and discussed in detail on technological front, however certain aspects at the outset can be attributed to both behavioural or technical.
Health Anxiety
Although no substantial evidence of negative outcomes of wearable technologies is reported, however as these smart wearables highly influence behavioural pattern of an individual, there is high probability of development of health anxiety. Consistent monitoring of health metrics in absolute scenarios can create an unwarranted panic situation for an individual. Thus, this data needs to be corroborated with other health metrics like – age, time of day, physical exertion, or routine etc., any action needs to be taken only in consultation with the physician.
Inaccuracy of data
Moreover data inaccuracy due to sensor reporting or device malfunctioning can also lead to inappropriate decision making for certain immediate concerns that might need critical attention. Like in case of overexercising or overeating. Place of usage of these devices on different parts of the body can also cause variability in data capturing which can also report inaccurate data.
Electromagnetic Field (EMF) exposure to human body
These smart wearable devices generally follow standard prescribed EMF threshold values, however, consistent exposure or over exposure of human body to EMF can lead to severe pain, nausea. Today’s modern lifestyle has left human body to tremendous exposure to EMF. EMF energy arriving at the human skin is dominated by the distance between the EMF emitting device and the skin.
Does Fitness Tracker / SmartWatch steal your data
Data Privacy is one of the major concerns for these wearable devices. Fitness trackers usually store data in the device which can later be transmitted to the computer through USB. Smart watches transmit data to app paired with mobile. No such stringent data privacy guideline is laid out to keep check on data leakage, if any.
How inaccurate is Fitness Tracker / Smart watches
Inaccuracy of fitness tracker / smartwatch can be majorly attributed to the placement of sensor on the part of the body. Placement of device on Ankle is reported to be highly recommended leading to minimal error. Smart Ring is considered highly reliable just because of its presence on fingers.
Here’s the list of Mean Absolute Percentage Error Level based on the placement of Sensor on Human Body
| Device | MAPE (Mean Absolute Percentage Error) |
| Ankle and Thigh | 1% |
| Waist | 3% |
| Wrist | 15% |
| Overall (normal speeds) | 7% |
| Overall (slow speeds) | 40% |
Source:https://ijbnpa.biomedcentral.com/articles/10.1186/s12966-022-01350-9
Following table elaborates the kind of error you can expect from the fitness tracker / Smart watches.
| Problem | What Happens |
| Heart rate errors | Fitness trackers often guess heart rate too low. |
| Calorie tracking mistakes | They usually underestimate how many calories you burn. |
| Accuracy issues | Things like exercise type, wrist position, and skin can affect results. |
| Step count errors | They miss about 9% of steps on average. |
| Sleep tracking mistakes | They overestimate sleep time by 10% and miss wake times. |
| Aerobic capacity errors | They overestimate VO2max by 15% at rest and 10% during exercise. |
Conclusion
With the introduction of smart wearable, health management has come a long way from reactive to proactive approach. Health management has become more of identifying disease at a very early stage leading to early diagnosis and cure. Data display wrt steps counting / calorie spent on fitness trackers have a behavioural motivation to work towards a more healthy lifestyle. Reflection of result over display screens push for a more active approach, bringing a positive outlook in todays fast paced lifestyle. Although these data inputs should be taken into consideration with actionable insights from consultation with physicians, as acting alone on data from these trackers in absolute might not be justified based on your daily lifestyle.
Frequently Asked Questions
Should I Purchase Smart Watch or Fitness Tracker
Selecting the device depends on your requirement and budget. Identifying the purpose of device can help in zero-ing down on device. For basic tracking wrt calorie burning, HRV, body temperature, steps counter – simple fitness tracker can solve the purpose at lower cost. Smart watch can be a better fitment, in case you plan for multi-functional device which helps in communication and managing notifications.
Are these Smart Wearable devices accurate
Accuracy of data depends on the physiological status and placement of fitness tracker sensor on the body. Table mentioned above reflects, tracking sensor placed on anklet in much more accurate compared to wrist or other part of body. Physiological status like sweat, overexertion can lead to inaccurate tracking by sensors.
How much can I trust my Fitness Tracker for health data
Health data from these device can help you with preliminary data for proactive actions. Action on these data should be taken in consultation with physician.
How should I use fitness tracker
Fitness tracker is ready to use device with basic Body Mass Data Input from the user. It displays basic data on display screen for corrective health actions. Data is stored in the device which can be downloaded using an USB.
How to pair up Smart Watch
Smartwatch has to be paired with a smart phone with connecting through an app. Basic BMI data input in the app and your Smart Watch is ready to use. Health management data is usually stored on cloud servers accessible any time.