Wearable devices have increasingly become a part of our digital lives, in no small part because of their health and wellness value. Each year, these smart bands, watches, rings, earbuds and headsets become smaller, more compact and more capable. They have the potential to provide users with invaluable information that isn’t available from a smartphone alone.

In a world where data is digital gold, I believe that health data is a defining factor for wearables. In this post, I want to explore the multi-faceted benefits of wearable devices, the technology driving them and how they will improve our digital health and wellness experiences.

Smartwatches and bands like the Galaxy Watch5 and Watch6 are the most mature and prominent wearables. However, I do not believe that the smartwatch is the best wearable technology for capturing health data, in terms of either the ability to obtain health measurements or the accuracy of those measurements. I believe that smart rings have more potential to capture the most data and to do it more accurately because of its location on the body.

I also want to delve into the software side of things and talk about how different digital ecosystems are innovating and creating mindful health and wellness platforms. Let’s dive in.

Defining health and wellness

I want to begin by defining what we mean when we say health and wellness. Health is defined by the World Health Organization (WHO) as “a state of complete physical, mental and social well-being,” and wellness is defined by the National Wellness Institute as the “active process through which people become aware of, and make choices toward, a more successful existence.” What is the purpose of being in a state of physical, mental and social well-being, and how do we measure a successful existence? We are always growing older, and our health and wellness, as defined above, are never static; chronic killers are always challenging them.

Wearing smart watches and bands cannot make us any more or less healthy by itself. However, data from these trackers definitely helps us assess our personal health and well-being.

Anatomy of smartwatches and bands

Before I jump into specific measurements and how wearables help us improve our health, I want to discuss the sensors that gather data. Not all sensors are the same, and some measurements are more helpful than others for assessing our sleep, diet and exercise. These sensors are the most prominent in gathering important data for wearables:

• Photoplethysmography (PPG) sensors optically measure the volumetric variations of blood circulation.
• Electrocardiogram (ECG) sensors measure the electrical activity of the heart.
• Temperature sensors measure the temperature of the skin.
• Bioelectrical Impedance Analysis (BIA) measures the body composition of the wearer by sending a small alternating current from the wrist of one arm to the fingertips of the other arm and measuring the resistance.

The PPG sensor is primarily used to measure a person’s heart rate, heart rate variability (HRV) and oxygen saturation in the blood. ECG sensors monitor the wearer’s heart rhythm to identify potential abnormalities. Many smart watches also have temperature sensors and use GPS to accurately track distance and movement.

Striving for more from wearable sensors

These sensors have the potential to be a gold mine of data for health and wellness. The PPG signal, for example, can be used to extract valuable information about the heart and respiratory system, including blood pressure and respiratory rate. The challenge for PPG sensors, especially in the wrist, is that they are prone to be misled by motion artifacts and environmental noise, compromising their accuracy and efficiency. Motion artifacts could be anything from the movement of the wrist during exercise or the PPG sensor on the wrist and can motion artifacts can be mitigated with the help of motion sensors.

PPG sensors use light to penetrate the wrist, then measure the light that reflects off of the blood vessels there. Most smartwatches use red and green light; using longer wavelengths, such as infrared light waves, allows the  sensor to better penetrate the skin and obtain accurate measurements. Research has shown promising results that bioimpedance data from a wearable could even be used to estimate blood glucose levels (BGL). I believe blood pressure, BGL and respiratory rate are only a few measurements with considerable promise to create huge benefits for wearables. Considering that the number one cause of death is heart disease, and that heart disease is an accumulating health risk, it is imperative that people at risk measure their blood pressure regularly. Having a wearable on the wrist or finger makes the process of tracking blood pressure much easier and more convenient, potentially leading to better lifestyle choices and healthier habits.

While wearables cannot reliably measure blood pressure, BGL and respiratory rate just yet, many other measurements are already helpful in providing the necessary information for pursuing healthy habits. Let’s take a deeper look at some of the key measurements providing sleep and fitness information.

Measuring sleep

Sleep has a significant effect on a person’s body and mind, and good sleep can reset and strengthen a person’s cognitive and physical health. Sleep quality is not as simple as getting eight hours of sleep; rather, it involves what your body is doing while you are asleep. Tracking sleep stages, body movement, temperature, blood oxygen and snoring could help a person assess which habits they need to change to optimize sleep.

Samsung Health and the Google Fitbit app offer sleep scores derived from estimated time asleep, how much of that time is spent in different stages of sleep and the amount of movement during sleep. Using motion detection and the heart rate monitor, wearables can determine when we are in different sleep stages and help us determine optimal times to go to sleep and wake up.

Where I believe Samsung and Fitbit excel is by offering sleep profiles. While the sleep scores give a grade for the quality of sleep during the night, the sleep profile gives a better idea of sleeping habits that affect the quality of sleep over a period of time. For Samsung, this is gauged to a week of consistent sleep tracking; for Fitbit, it is two weeks.

These sleep profiles offer a digestible way to understand how you sleep and how to improve it. For instance, Moor Insights & Strategy junior analyst Jacob Freyman tracks his sleep on the Fitbit app, where he usually gets a sleep profile of the slow-to-sleep Tortoise and sleep scores consistently in the 80 to 90 range. After having a baby and waking up much more often in the middle of the night, his sleep score changed to the Dolphin, the sleep profile type with the most sleep variability.

Samsung sleep coaching. Source Samsung

Samsung recently introduced sleep coaching with its Galaxy Watch6 and Watch6 Classic. I am still in the process of reviewing these devices and the sleep coaching functionality. However, Samsung has worked with the National Sleep Foundation to push for better sleep, especially after the pandemic. Getting quality sleep is not something that just happens during the night; it is intertwined with healthy habits during the day, like eating at optimal times and being exposed to sunlight at the right time of the day. Samsung is pushing its sleep initiative beyond the night, involving technologies like SmartThings for controlling sleep environments.

Measuring fitness

Tracking metrics such as heart rate during workouts and throughout the day gives users a better understanding of their overall health, as well as enabling personalized targets to shoot for when doing specific exercises. Samsung recently introduced new heart rate zones to the Samsung Health app. Google Fitbit, Apple and Garmin also use heart rate zones that are great at measuring a person’s physical exertion during different activities.

Heart rate is also useful in estimating a person’s VO2 max, which tells you how efficiently your body takes in oxygen during periods of high exertion. It is measured using an algorithm that combines heart rate data with the pace at which a person is moving. Although the ideal method of measuring VO2 max involves wearing a breathing mask and having a clinician carefully record results, wearables are capable of estimating VO2 max pretty accurately. VO2 max is a great long-term metric for understanding age-related fitness health. In fact, Garmin uses VO2 max to determine fitness age by comparing a person’s VO2 max to the average for people their age. Garmin’s fitness age is a clever way to get people to care about their VO2 max.

Although it is one of the simplest measurements, step tracking is also good for helping a user understand how much movement they are getting in a day. While step tracking is not perfectly accurate on most wearables, it is usually within the ballpark for helping a person track their daily step goal, especially when GPS is involved.

While physical measures are extremely helpful, it’s important to remember that fitness has a mental component, too. This mental aspect is much harder to measure for smartwatches and other wearable devices. That said, there are some things we can measure, such as stress, that play a significant role in our mental health.

The Fitbit app uses heart, sleep and daily activity data gathered from a smartwatch to assign the user a stress management score. This score gives a rough estimate of the amount of stress in your life, how well you may deal with stress based on sleep data and how sensitive you may be to stress. It uses heart rate data to detect signs of stress or when the body releases stress hormones such as cortisol . While these are certainly not direct measurements of stress hormones in the body, I believe they can be helpful in managing stress. Samsung also offers a method of measuring stress and gives helpful tips and feedback for managing stress, such as breathing techniques.

Source Fitbit

Wrapping up

Sleep, diet and mental and physical fitness are all closely connected. The better your sleep quality, the more physically active you are and the better your personal nutrition, the more ready you will be to take on the day and manage yourself mentally. Of course, unless you care about your health and wellness and mindfully set goals to improve them based on the feedback you get, the data generated by wearables will be mere numbers.

Wearable technology has the potential to positively affect our health and wellness by giving us the proper health data to set and track appropriate goals and habits. While many of today’s wearable measurements are only estimates, and we are limited by the number of useful metrics available, I am hopeful that wearable technology will continue to get better in this regard. As sensor technology and algorithms become better and more accurate, I believe we could see an abundance of innovative wearable devices that have a beneficial impact on health and wellness.

I also believe that health platforms such as Samsung Health, Google Fitbit, Garmin and Apple Health should continue to build out health and wellness features that make their accumulated data more usable for their wearers. The data is only the means to the end of living a longer and healthier life, and if the end goal is not well understood, the data won’t really promote healthy lifestyles.