Should I rely on a smartwatch to monitor my health? A doctor's perspective

I’m cycling on a recumbent bike, wearing my smartwatch, hoping that tracking my fitness and health data will motivate me to exercise more consistently.

Smartwatches have evolved beyond just texting, music, and checking the time; they've become central to many people's health routines. But can they detect heart issues like irregular rhythms or even heart attacks? What about monitoring oxygen levels or blood sugar? And can they assist with sleep tracking?

In 2023, over a quarter of the U.S. population used a smartwatch or a similar device for health and fitness tracking, according to Insider Intelligence/eMarketer. By 2026, over 100 million Americans are expected to be using smart wearable devices.

To answer my questions about smartwatch health and fitness features, I consulted Dr. Leana Wen, a wellness expert with Dinogo. Dr. Wen is an emergency physician and clinical associate professor at George Washington University. She’s an avid exerciser and a smartwatch user, having previously served as Baltimore’s health commissioner.

Dinogo: Let’s begin with the fundamentals. How would you describe a smartwatch, and how can people use it to monitor their exercise and fitness?

Dr. Leana Wen: A smartwatch is a wearable tech device that looks like a regular wristwatch. Many of these watches are Bluetooth-enabled, allowing them to connect to your smartphone. This lets users access features like receiving messages, listening to music, and even answering calls and emails directly from the watch.

Many smartwatches also offer fitness and health tracking features. One of my favorite functions is the step tracker. Research has shown that setting daily step goals can lower the risk of heart disease and extend life expectancy.

A March study, for example, found that for people who are mostly sedentary, walking 9,000 to 10,000 steps a day reduced their risk of heart disease by 21% and lowered the likelihood of early death by 39%. Another study, published last year, found that even as few as 4,000 steps daily could decrease the risk of premature death.

Wearing a smartwatch helps track daily step counts. It can remind users of their step goals and serve as motivation to keep moving throughout the day.

Dinogo: As a runner and triathlete, how do you and other active individuals use your smartwatches for training?

Wen: Many active individuals track their heart rate during exercise to ensure it stays within a target range. Endurance athletes, like runners, cyclists, and triathletes, typically train in what's known as zone two, or the endurance zone. This is when the heart rate stays at 70% to 75% of the maximum heart rate, allowing them to work hard but still maintain the activity for a prolonged period.

A smartwatch with a heart rate monitor can help athletes stay within their target heart rate zones. More advanced models offer additional fitness features, such as tracking pace, distance, and running cadence, and some can even identify the type of exercise being performed, useful for those switching between different sports. Certain models come with GPS and can provide navigation for the user.

Dinogo: I’ve seen smartwatches that claim to detect heart issues. Can they really help identify heart attacks?

Wen: Smartwatches are not approved to diagnose heart attacks. If you're experiencing chest pain and your smartwatch shows normal heart rate and ECG readings, that doesn’t mean you're in the clear. You should seek immediate medical attention.

It's crucial to understand that smartwatches can't replace medical-grade monitoring equipment. If your doctor recommends a specific heart monitor, it’s important to follow their advice.

Dinogo: What about irregular heart rhythms?

Wen: Many smartwatches claim to detect irregular heart rhythms, such as atrial fibrillation. This type of heart rhythm can increase the risk of stroke if left untreated, making it vital to diagnose early on.

The Apple Watch, Fitbit Sense, and Samsung Galaxy are among the few smartwatches that have been approved by the US Food and Drug Administration to detect irregular heart rhythms in certain adults who do not have a history of atrial fibrillation.

If someone without a previous history of heart issues receives such a notification, they should reach out to their primary care provider to discuss next steps, which may involve an in-office EKG and ongoing medical-grade monitoring.

It’s important to also pay attention to how your body feels. If you experience heart palpitations, shortness of breath, chest pain, dizziness, or any unusual symptoms, don’t rely solely on your smartwatch’s normal readings—contact your doctor immediately.

Dinogo: How about using smartwatches to measure oxygen levels or blood sugar?

Wen: The accuracy of smartwatches in measuring oxygen levels can vary. In my view, if you need to monitor your oxygen levels due to underlying lung conditions, it's best to use specialized equipment for this purpose. A pulse oximeter is affordable, portable, and generally reliable, although recent studies indicate they may be less accurate for individuals with darker skin tones.

Regarding blood glucose, the FDA issued a strong warning this year advising consumers not to “buy or use smartwatches or smart rings that claim to measure blood glucose levels.” These devices may not provide accurate blood glucose readings.

People with diabetes who rely on precise glucose measurements to adjust their medication might risk under- or overdosing if the readings from smartwatches are inaccurate. This could be hazardous. They should continue using the devices prescribed by their healthcare providers, as smartwatches currently cannot match the accuracy of medical-grade equipment.

Dinogo: Can smartwatches help improve sleep?

Wen: Possibly. Many smartwatches track your sleep, providing insights into how long you sleep and how much time you spend in each sleep phase.

Personally, I find this data valuable. I've always struggled with sleep, so I try various strategies, such as meditation before bed, reading, or changing my sleeping position. I appreciate the sleep quality and duration information my smartwatch provides, as it helps me correlate environmental changes to see what improvements work for me and which ones don’t.

I also appreciate the feature on my smartwatch that tracks heart rate variability during sleep. This measures the fluctuations in time between each heartbeat. Everyone has a different baseline, and by knowing your own, you can monitor changes over time.

For example, I've noticed that when I don’t sleep well or after intense training periods, my heart rate variability decreases — an indicator of stress and insufficient recovery. With this data, I can prioritize more sleep or adjust my training accordingly.

The main takeaway I have about smartwatches is that they are perfect for people who enjoy tracking data. I’m one of those people; I appreciate the data my smartwatch provides, as it helps guide and motivate me. However, some people might find all the data overwhelming or even stressful. The key is to use it in a way that works for you. Smartwatches should be a helpful tool in reaching your health and fitness goals, not an added source of pressure or stress.

Dinogo: I’ve heard that smartwatches might not be ideal for people who are overly focused on exercise. What do you think?

Wen: Some individuals might actually benefit from stepping back from data tracking. Exercise should be enjoyable, and if constantly monitoring your stats becomes stressful, it might be worth leaving the smartwatch behind once in a while to see if it makes the experience more enjoyable. Also, it’s always crucial to listen to your body.