CNN
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I wear my smartwatch while riding my recumbent bike, hoping that tracking my fitness and health metrics will motivate me to exercise more.
Smartwatches are no longer just for texting, music, and telling the time (how corny), but for some, they’ve become essential for keeping track of their health. But can they detect cardiac conditions like irregular heartbeats and heart attacks? Can they be used to measure oxygen levels and blood sugar? Can they even help you sleep?
By 2023, more than a quarter of the U.S. population will be wearing a smartwatch or other connected device used to track health and fitness. Insider Intelligence/eMarketerBy 2026, it is predicted that over 100 million Americans will be using smart wearable devices.
To answer some of the health and fitness questions about smartwatches, I spoke with CNN health expert Dr. Leana Wen, an emergency physician and clinical associate professor at George Washington University who owns a smartwatch and loves exercise, and who previously served as Baltimore City’s health commissioner.
CNN: Let’s start with the basics: How would you define a smartwatch, and how can it be used to track exercise and fitness?
Dr. Leana Wen: A smartwatch is a type of wearable technology device that resembles a wristwatch. Many are Bluetooth-enabled, allowing the watch to connect to a smartphone, allowing the user to access some of the smartphone’s functions, such as receiving text messages, listening to music, and answering calls and emails.
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A smartwatch with a heart rate monitor can help athletes track their heart rate and keep it in a consistent range.
Many smartwatches also allow you to track your fitness and health data. One feature I particularly like is step tracking. Studies have shown that setting a daily step goal can help reduce the risk of heart disease and early death.
A study published in MarchFor example, for people who spend most of their day sitting, walking 9,000 to 10,000 steps a day was found to reduce their risk of developing cardiovascular disease by 21% and their chances of premature death by 39%. Published last yearIt has been found that taking just 4,000 steps a day can reduce the risk of premature death.
Wearing a smartwatch can help you track how many steps you take throughout the day, remind you of your goals, and motivate you to take more steps.
CNN: You’re a runner and triathlete. How do you and other active people use smartwatches to help with training?
Wen: What many active people do is track their heart rate while exercising and try to keep it in a certain range. Many endurance athletes, such as runners, cyclists, and triathletes, spend the majority of their training in what is known as zone 2, or the endurance zone. This is because your heart rate is 70% to 75% of your maximum heart rateIt feels like you’re working out, but not so intense that you can’t continue.
Smartwatches with heart rate monitors can help athletes monitor their heart rate and stay within their target zone. More advanced smartwatches have additional fitness features such as tracking pace, distance, running cadence, and some can even detect the type of sport being played for those transitioning between different disciplines. Some even have GPS data and can provide directions to the wearer.
CNN: We’ve seen smartwatches that claim to detect heart disease. Can they really be used to warn you of the signs of a heart attack?
Wen: Smartwatches are not approved for diagnosing heart attacks. If you have chest pain and your smartwatch shows that your heart rate and ECG are normal, it doesn’t mean you’re OK. You should seek medical attention immediately.
It’s important to remember that a smartwatch is not a replacement for medical-grade monitoring equipment, and anyone who has been advised by their doctor that they need specific cardiac monitoring equipment should follow that advice.
CNN: What about arrhythmia?
Wen: There are many smartwatches that claim to detect an irregular heartbeat called atrial fibrillation, which is important to diagnose because if left untreated, it can increase the risk of stroke.
of Apple Watch, Fitbit Sense and Samsung Galaxy They are among the few smartwatches cleared by the U.S. Food and Drug Administration for their ability to detect the irregular heartbeat in some adults with no history of atrial fibrillation.
People who have never had a heart condition before and receive such a notice should contact their doctor and ask about next steps, which may include an in-office ECG or ongoing medical-grade monitoring.
Again, you should listen to your body too: if you experience palpitations, shortness of breath, chest pain, dizziness, or any other unusual sensations, contact your doctor, even if your smartwatch says your heart rate and rhythm are normal.
CNN: What about using smartwatches to measure oxygen levels or blood sugar levels?
Wen: The accuracy of smartwatches’ oxygen level measurements varies. In my opinion, if you have underlying lung conditions, for example, and need to monitor your oxygen levels, you should use a dedicated device. Pulse oximeters are cheap, portable, and generally reliable, but Recent research People with darker skin are less likely to suffer from this condition.
Regarding blood sugar levels, the FDA issued a strong warning This year, consumers are being advised not to “purchase or use smartwatches or smart rings that claim to be able to measure blood glucose levels” as these devices may measure blood glucose levels inaccurately.
Diabetics need to accurately measure their medication doses, but if their blood glucose measurements are inaccurate, they may take too little or too much of their medication, which can be dangerous. People should understand that smartwatches cannot yet replicate the accuracy of these medical-grade devices and should continue to use their measuring devices as directed by their doctor.
CNN: Can using a smartwatch help you sleep?
Wen: Yes, many smartwatches can track your sleep and tell you how long you slept and how much time you spent in each sleep stage.
Personally, I find this information useful. I’ve always had trouble sleeping and am constantly trying different things like meditating before bed, reading books, sleeping in different positions, etc. I like the data that a smartwatch provides me on the quality and length of my sleep. I can correlate this data with the changes I’m making to my sleep environment to see what changes are working and what aren’t.
I also like the smartwatch’s ability to track heart rate variability while you sleep, which measures the change in the time between heartbeats. Everyone has a different baseline for heart rate variability; knowing your own baseline can help you track changes over time.
For example, we found that if you haven’t had enough sleep or have recently done some intense training, your heart rate variability will be lower, indicating increased stress and slower recovery. Based on this data, you can prioritize your sleep or adjust your training accordingly.
My biggest takeaway from smartwatches is that they are beneficial for people who love data, and I am one of them. I love them because they provide useful data to inform and motivate me. Others may find all the data useless or even stressful. The key is to choose what works for you. A smartwatch is a tool to help you achieve your health and fitness goals, not something that adds pressure or stress to your life.
CNN: We’ve heard that smartwatches aren’t necessarily a good idea for people who are particular about exercise.
Wen: There is Some people You might benefit from taking a short break from tracking your data. Exercise should be fun and enjoyable. If all the data is adding to the pressure and stress, it’s worth leaving the smartwatch at home and trying to see if exercising becomes more enjoyable. It’s also always important to listen to your body.
