What Are Smart Rings and How Do They Support Your Health? Our Hands-On Experience

The COVID-19 pandemic was a nightmare for humankind; however, it had a positive effect on our mindsets; we realized that health should never be taken for granted. This sudden realization led some to bake homemade bread or grow wild tomatoes, while others decided to invest in health tech tracking technology like smartwatches and rings.

While smartwatches have been around for a while, largely thanks to Apple, their younger siblings — smart rings — have experienced a surge in popularity since the lockdown. More comfortable and easier to wear than their counterparts, these devices promise to track, measure, and guide you through various health metrics, including heart rate, body temperature, stress levels, and sleep patterns.

Like many bread makers and tomato growers, I became more conscious of my health, switching to a more balanced diet and following YouTube workouts. However, these practices did not last — I still struggle to make the best choices and keep my bad habits under control.

That’s why I decided to dig deeper into the smart ring market to determine whether these devices are just a fashion statement or if they can actually help monitor our health and inspire long-lasting lifestyle changes. To uncover this mystery, I have spent almost a month diving into scientific research, gathering expert insights, collaborating with my in-house researchers, and analyzing various smart ring communities and brands. My research went as far as asking some of my friends to wear the devices to gain a more comprehensive view — something they were particularly excited about. After all this hard effort, I have finally cleared some of my doubts, and I am excited to share all I have learned.

Smart rings: from a novelty to a wellbeing trend

Wearable health tech started to gain momentum in the 2010s with the launch of the Fitbit smartwatch, which paved the way for many providers to introduce various wellness tracking features. However, rings would still take a few years to compete with these devices.

The first ever smart ring, launched by a British company McLear in 2013, was designed exclusively for contactless payments and did not include any health-related features. However, as wearable health tech became more popular, smart rings joined the movement, enabling users to monitor movement, body temperature, heart rate, stress, and other key biometrics.

Unlike smartwatches, rings don't have a screen to showcase metrics; instead, they rely on a Bluetooth connection to send health data to your smartphone.

How smart rings support your health: key features

Now that we have answered what a smart ring is, we can delve into their features and technology. Nevertheless, it is important to note that these are the most common elements we encountered — some brands may offer additional activity tracking features. With that in mind, let’s see what smart rings offer.

Cardiovascular health monitoring

Smart rings utilize infrared photoplethysmography (PPG) technology to gather insights into cardiovascular health. This technology uses a light source and a photodetector at the surface of your skin to measure the variations in blood circulation. These variations allow estimating heart rate variability, blood oxygen saturation, blood pressure, and artery stiffness.

Among the different sensors featured in these devices, the PPG is the most studied one for its proposed accuracy in heart rate tracking and overall cardiovascular health monitoring. However, most studies note that they are considerably less accurate than medical-grade technology.

In one study with 35 healthy individuals, researchers compared the heart rate and heart rate variability measured by the Oura ring with an ECG during the night. Results showed that some health parameters matched the medical-grade measurement, but most were simply inaccurate.

Body temperature monitoring

Most rings have a sensor known as a thermistor, which estimates body temperature based on your skin temperature. Most smart rings often promote this feature as essential for assessing stress levels and identifying other bodily issues. However, based on my research, science disagrees.

A systematic review of sensors and functionalities of wearable health tech indicates that these devices may not accurately reflect your core body temperature. Researchers highlight that your skin temperature is a few degrees Celsius lower than your body's.

Moreover, they stress that skin temperature fluctuates based on environmental conditions. Considering these two aspects, it may be hypothesized that the sensor will not be accurate.

Menstrual cycle

Smart ring providers such as Oura, Samsung Galaxy, or Evie report using various sensors to support women's health. They mostly rely on their body temperature feature, which they claim to use to track menstrual cycles and fertility windows.

Various studies have examined the accuracy of these devices, yielding promising results. In a pilot study with 22 participants, researchers used a ring to analyze temperature changes during the menstrual cycle. They discovered that the temperature readings were consistent with oral temperatures taken with ambulatory equipment.

A separate study with 26 participants was consistent with the former findings, indicating that rings could be beneficial for monitoring menstruation. This study also detected a significant temperature drop around ovulation, highlighting that these devices could be an additional tool for fertility tracking.

Although the results are promising, I did not find significant big-sample studies or meta-analyses. The limited body of research led me to seek the expertise of Maria Cerro, an endocrinologist and nutritionist with experience in hormonal disorders and fertility treatments.

Some years ago, it became quite popular to measure body temperature, especially in fertility treatments. Right now, it is not so popular because we know it is inaccurate. However, a ring may be useful in some cases, especially if your doctor asks you to monitor certain biomarkers. Also, a ring makes the temperature measurement more convenient and easier than traditional thermometers.

Maria Cerro

When I asked her about the limited studies on smart rings, she agreed with my perspective — they are not 100% accurate and further research is needed.

"The body of research is slim, and many of these studies are conducted during sleep or in controlled environments that may not reflect real-world results. That's why you should always consult your doctor if you have any health concerns or want to start a fertility treatment," she added.

Stress and mental well-being

Most smart rings combine various metrics, including heart rate, heart rate variability, body temperature, and movement, to estimate your daily stress levels and provide tips on reducing them.

Research suggests a connection between stress and decreased parasympathetic regulation. This regulation impacts heart rate, heart rate variability, and respiratory rate — changes that your smart ring could potentially detect.

A study with 525 college students explored this subject further, indicating that sleep data from smart rings could help predict stress. Interestingly, some experts do not consider the rings as promising as research. Maria José Lorenzo, a psychiatrist with over 20 years of experience, highlighted the negative impact these devices may have on mental health.

Honestly, I doubt these smart rings could be helpful for your mental health. While they are promoted as a tool to shift lifestyle habits, they may generate the opposite effect. Constant monitoring of health metrics can create obsessive behaviors and paranoia about your well-being. Moreover, it could also be detrimental to self-confidence as you may not fulfill the expectations and goals the device marks for you.

Maria José Lorenzo

Sleep quality and circadian rhythms

Smart rings conduct a sleep analysis by tracking heart rate, blood oxygen, and sleeping cycles. They may also include other features, such as a snoring score and a recovery metric that indicates how energized you are to face the day.

In the sleep-tracking universe, the golden standard is polysomnography (PSG), which includes a variety of signals like brain activity, eye movements, muscle activity, blood pressure, heart rate, and more. While smart rings are not as accurate as PSG, they have caught the eye of researchers due to their potential to monitor sleep comfortably at home.

The current evidence on smart rings for sleep tracking is still quite limited and conflicting. While some small studies highlight their potential, bigger-sample studies indicate that they can overestimate or underestimate some sleep parameters. Interestingly, we found a study that compared the precision of several health tech devices on 35 individuals overnight. In this study, the Oura ring outranked the accuracy of Fitbit and Apple smartwatches in various sleep parameters, including wake, light sleep, deep sleep, and REM sleep.

We spoke about sleep tracking with Dr. James Giordano, a professor of Neurology at Georgetown University Medical Center. He also highlighted the limited accuracy of smart rings and shared with us some practical advice.

Any device that portrays sleeping patterns could be useful to evaluate your sleeping habits. For example, if you are fatigued or feel tired throughout the day, it may be interesting to check what happens during sleep and even apply some changes to your routine. That being said, these devices are not as accurate as medical-grade and should not be used to self-diagnose. Always seek medical evaluation if you suspect having sleeping issues.

Dr. James Giordano

Physical activity

Physical activity is measured with two sensors: an accelerometer and a gyroscope. The accelerometer tracks movement and speed, while the gyroscope helps determine orientation. Smart rings gather data from these motion sensors, as well as from the PPG and body temperature trackers, to understand how physical activity impacts the body.

Although research in this area is limited, we found a study focusing on the accuracy of smart rings in measuring caloric expenditure and steps. The results indicated that these devices were far from accurate, with researchers highlighting the need to improve these devices, especially their energy expenditure estimation.

Another study on step count was consistent with the latter, indicating that the Oura ring overestimated step count in comparison to ActiGraph, a medical-grade device to detect motion.

Lastly, a meta-analysis on wearable tech devices supported these findings, indicating that they may be useful for estimating step count but should not be relied upon for calorie expenditure.

Smart rings to the test: advantages and disadvantages of health tracking

Smart rings are gaining traction in the scientific world for their potential applications in health. While these devices may seem promising theoretically, we wanted to check whether they deliver in practice, so we contacted several brands and asked them to provide us with rings for testing in exchange for an honest review.

Then, we have gathered a panel of testers to review the rings. Alejandro (male, 2D artist, 42), Saimonas (male, WellnessPulse content manager, 29), and Justin (male, QA tester, 27) tried Ultrahuman, Circular, and RingConn's devices, respectively, for a week and shared their feedback with me. Unfortunately, women did not participate in the testing experience — not even myself — as the sizes of the rings we received were too large.

Usability and app

The first thing I discussed with my testers was their initial impressions of the device. The three men expressed satisfaction with the setup process; however, they had more critical views regarding usability.

“Even though the app is straightforward, I think the metrics are not explained comprehensively. Overall, I felt it did not really provide the big picture that I was hoping for,” Saimonas said.

The testers also shared that most of the app's metrics are easy to understand for those familiar with wearable health tech. Nevertheless, they raised concerns about specific features.

“There are some metrics that I had some knowledge about like HRV (heart rate variability), HR (heart rate), or SPO2 (oxygen saturation). However, others, such as the ‘stress index,’ are borderline confusing,” Justin mentioned.

Accuracy

I also asked my testers their thoughts on the accuracy of the devices, and surprisingly, all of them had complaints. While Saimonas was particularly critical about the step count, Alejandro raised concerns about the stress levels. Additionally, Justin felt that the data on sleep and physical activity were inaccurate.

“At rest, a lot of the metrics seem accurate, but everything becomes a bit more nebulous during sleep or exercise. For example, sometimes my SPO2 levels would drop to 90 (something that would normally require urgent medical care), or my pulse wouldn’t climb above 120, even when doing intense exercise,” Justin explained.

Lifestyle changes

The three testers were happy with the app's customization options but felt it provided basic advice for improving results or monitoring specific goals. Alejandro and Saimonas admitted that the ring did not help them change particular habits. At the same time, Justin was more optimistic, mentioning that the ring inspired him to optimize his sleep schedule.

Alejandro and Justin reported feeling uncomfortable wearing the ring while sleeping and working out. My testers particularly criticized the latter aspect.

"The ring probably aligns best with runners, swimmers, or exercises that don't require grip strength. Now, if you are a gym goer, it becomes a no-go. Exercises with dumbbells and barbells are uncomfortable, and this also applies to pull-ups and other floor exercises. On top of that, there's always the feeling that it can get damaged when lifting weights," he added.

Personal thoughts

Lastly, I asked my testers about their favorite and least favorite aspects of the device. Alejandro enjoyed his sleeping insights, but he did not like the physical activity tracker. In contrast, Saimonas enjoyed that the ring could help him create a community, but he was not happy that the ring only fitted one of his fingers. Justin liked the ring's aesthetics but found it uncomfortable to wear. Interestingly, none of them felt particularly passionate about the device and expressed reservations about recommending it.

"In general, I wouldn't recommend smart rings, as I feel like they're kind of a catalyst for forming an unhealthy relationship with one's own health. They can lead to overly relying on data or interpreting metrics in the wrong way. If somebody truly needs to track specific data, it would be best to purchase more accurate and specialized activity monitoring tools," Justin concluded.

Limitations and considerations

As we have explored throughout this article, smart rings may be valuable tools to inspire lifestyle changes. However, they should not be relied upon to diagnose or treat any health conditions. We spoke about the limitations and accuracy of these devices with Antonio Sáez Jiménez, a cardiologist with over 20 years of experience who shared key insights.

Smart rings and wearable health tech are interesting devices to monitor health. While they may not be as reliable as medical-grade equipment, they are still valuable tools for detecting irregular heart rates due to their high sensitivity and specificity. That being said, they still cannot accurately detect health conditions.

Antonio Sáez Jiménez

We also asked Antonio whether we should be concerned about abnormal results from our smart ring and what the best course of action would be in these cases.

“It is important not to panic right away. A professional should evaluate the results and determine if further examinations are needed. Moreover, the accuracy of these devices is still not clear-cut. We had a case where a smartwatch user came to the office with a high heart rate frequency that turned out to be a false alarm. The issue was that his watch was not properly attached to his wrist while working out. So, please always inquire with your doctor about results and avoid jumping to conclusions.”

Our researcher Dominyka Sitavičiutė, who has a background in MedTech, also joined Antonio in the discussion. She showed agreement with the cardiologist, especially highlighting the lack of personalization in devices compared to a doctor’s visit,

Leading smart rings for health tracking

While the smart ring market is extensive, we have decided to focus on the most popular brands: Oura, Samsung, Ultrahuman, and RingConn. Before diving into each provider, I want to once again clarify that neither my team nor I have received any affiliate compensation for promoting these rings — our evaluation is based solely on our own research. With that out of the way, let's get into the most popular smart ring brands and how they compare.

Firstly, I would say that most rings cover four basic features: movement, sleep, heart rate, and stress. So, if you are looking for a smart ring to address these aspects, most providers have you covered. However, I would like to stress that none of these devices are 100% accurate in their health data. Regardless of your chosen brand, do not expect a clear reflection of your well-being. The ultimate decision should focus more on your specific goals, which may lead to one provider or another.

Oura is a good match if you are looking for a ring that gives you a full rundown of data. With a clean and easy-to-use interface, this ring delves into aspects like cardiac age, cardio capacity, resilience, sleeping cycles, stress, and more. One of the features that users tend to highlight about the Oura Ring Gen models is their capacity to adapt to users' needs, recalculating goals depending on your body's condition day by day.

Another feature frequently discussed about Oura rings is its resilience score, which uses data from all its sensors to score your overall health for the day. Moreover, the Oura Rin Gen 3 and other models are frequently included in scientific research studies.

On the downside, I personally consider that Oura's pricing may not be accessible for everybody. In addition to the rings' excessive pricing, you will have to get a monthly subscription to use its app. Furthermore, if you are buying the ring to monitor your menstrual cycle, you will need to purchase a subscription to Natural Cycles for over $100 per year.

Ultrahuman, on the other hand, includes features that are very similar to Oura, but its app is available for free and features a menstrual cycle tracker without extra costs. Ultrahuman is also focused on nutrition and coaching, offering the opportunity to monitor caffeine intake, macros, etc. Moreover, the Ultrahuman app includes workout routines and tips on improving your goals based on your health data. However, some users have reported that the device's battery life is quite unreliable, and the app's interface may take some time to get a hold of.

Another big fan favorite is RingConn, which offers similar features to Oura and Ultrahuman, although its data is less comprehensive. Its interface is perfect for beginners as it is easy to navigate and allows manual input of various parameters. Moreover, RingConn shines on its sleeping insights, including a tracker to monitor the risk of apnea and enabling self-reports of sleep to calibrate its data. This device has better battery life compared to other brands, with the ability to last several days without needing to be charged.

The Samsung Galaxy Ring, launched in 2024, offers sleeping trackers, heart rate monitors, readiness scores, snoring trackers, and movement sensors. However, a key drawback is that the information displayed is quite limited and usually needs to be complemented with a Samsung smart watch or Samsung phone for more accurate readings.

How to choose the right smart ring for your health needs

After reviewing scientific evidence, discussing with experts about the devices, and gathering feedback from testers, I have compiled a list of key aspects to consider if you plan to purchase a smart ring. Let’s go through them.

1. Size. I cannot stress enough how crucial it is to choose the right ring size for your finger. An incorrect size will make you uncomfortable and lead to inaccurate measurements or data gaps. Before buying a smart ring, ask for a sizing kit and wear your trial ring for a few days. Keep in mind that your finger responds to various environmental changes, so make sure the ring is snug throughout your daily activities.
2. Materials. Before choosing a ring, you may want to consider its materials, especially if you have sensitive skin. Depending on your daily routine, you may also want to choose a water-resistant ring. If you plan to swim while wearing your ring, ensure it is fully submersible.
3. Pricing. Smart rings are not usually the most budget-friendly devices on the market; in fact, some can be quite expensive. Before buying, carefully evaluate your goals and choose a device that aligns with your needs and wallet. Be aware that some brands may charge a subscription fee for their app or specific features, so consider all these aspects when deciding.
4. Health goals. The landscape of smart rings continues to grow with each passing day. While most rings track heart rate, sleep, or stress, some models offer specific features that may benefit certain users. For instance, the Evie ring is more geared toward female health, while the Ultrahuman ring air may be more directed toward fitness enthusiasts. Establish your health goals and look for features to help you achieve your objectives.

Final thoughts: should you get a smart ring for health monitoring?

Initially, I had a very positive impression of smart rings. I believed they could be an easy way to monitor our health and encourage us to take action toward healthier behaviors. However, the more I learned about these devices, the more I realized that they may not be the right choice for me and many others.

Scientific research has shown that smart rings are far from accurate compared to medical-grade equipment. Therefore, if you were considering a ring to track specific health concerns, it may not be particularly valuable. Even my testers have complained about the inaccuracy of these devices when it comes to steps, sleep, or recording certain habits.

Don't get me wrong though, smart rings can still benefit some people. They could help support specific fitness goals or improve certain habits, such as enhancing sleep schedules or increasing daily step count.

Maria Cerro offers an interesting perspective on the type of person who might enjoy using these devices, which I feel summarizes this article's essence.

"Smart rings usually end up in the hands of youngsters, typically between the ages of 20 and 30. And even then, I only see them in those already physically active. This is because they can be great tools to monitor your progress, especially if you have specific goals in mind, like training for a sports competition or becoming more aware of your sleeping cycles. However, if you are not tech-savvy or do not have any particular goal in mind, I do not think you will find much value in them".