What Your Smartwatch Can—and Can’t—Tell You About Your Health
What Your Smartwatch Can—and Can’t—Tell You About Your Health
Smartwatches advertise an increasing number of health features, potentially detecting problems earlier and helping track known health concerns.
But how much can you really rely on a smartwatch?
Adam Bress, PharmD, MS, a population health scientist and cardiovascular clinical pharmacist, and cardiologist Jared Bunch, MD, both at University of Utah Health, explain the benefits and limitations of smartwatch-based health tracking.
What health conditions can smartwatches detect?
Some smartwatches use light-based sensors to measure blood flow in your skin. With this technology, devices can flag patterns that suggest:
- High blood pressure (hypertension)
- Atrial fibrillation (AFib), a common heart rhythm disorder
Smartwatches may detect AFib by detecting tiny electrical changes in your body as your heart beats.
Both hypertension and atrial fibrillation can go undetected for a long time because they usually have few or no symptoms. Left untreated, however, they can lead to serious health problems, including stroke and heart failure. This means early diagnosis is critical.
“Early diagnosis is a huge upside for wearable devices, especially in hypertension, which is an asymptomatic condition,” Bress says. “You can be walking around with hypertension for years and not know it. The promise that a wearable device could alert you that you might have hypertension is a really exciting potential innovation.”
What should you do if you’ve received an alert?
A smartwatch alert should be viewed as a signal—not a diagnosis.
If you received a health alert from your smartwatch, the next step is review those results with your health care team. In-clinic measurements are more accurate and, combined with other health information, can help you and your health care team decide whether the alert represents a real concern and make a plan to stay healthy.
“The goal is that, if you’ve been alerted that your heart rate’s abnormal, then you’ll go talk to your doctor,” Bunch says. “With atrial fibrillation, some people are at risk for heart failure; we need to manage the risk factors for that and also the disease itself. Some people are at risk for stroke; in many people, we need to start medications early to lower their risk. The goal is that earlier diagnosis will lead to improved care.”
What can’t smartwatches do?
Smartwatch health alerts aren’t perfect.
- Devices that detect atrial fibrillation are about 80–90% accurate, although many have the ability to record 30 seconds of heart activity to improve accuracy.
- Apple Watch hypertension notifications miss undiagnosed hypertension more than half the time.
- Many serious heart conditions, including heart attack, cannot be detected by smartwatches.
That means, whether or not you’ve received an alert, it’s important to stick to routine health screenings and see your doctor if you’re concerned about your health.
General blood pressure screening guidelines include:
- Adults under 40: Three to five years
- Adults over 40 or those with additional risk factors: Every year
Who can benefit most from smartwatch health tracking?
According to Bunch, smartwatch monitoring can be especially helpful for:
- People with risk factors for stroke or heart failure
- Those who want to closely track their health
- Individuals who suspect a heart issue but have not yet been diagnosed
These technologies can help people understand their heart activity and check for atrial fibrillation. Symptoms of atrial fibrillation include:
- Heart palpitations
- Fatigue
- Dizziness
- Shortness of breath
- Chest discomfort
- Loss of exercise capacity
Wearable health trackers can also be especially useful for people who have trouble accessing standard health care, whether due to financial barriers or living in rural or remote areas.
“These are tools that help us diagnose certain heart conditions or heart disease risk factors around traditional barriers of health care access,” Bunch says. “These tools help us make diagnoses earlier, even if your symptoms are not typical for the heart condition.”
Smartwatches aren’t a replacement for medical care, but they can play a useful role in spotting potential problems sooner.
“We are hopeful that these technologies can help to address problems earlier, when they can be reversed or their consequences are less severe,” Bunch adds. “I think their use is really valuable, and their capabilities to detect other problems are only going to increase over time.”
