Can a Fitness Tracker or Smartwatch Help You Live Longer?

Is the Future of COVID-19 in Wearables?

More than 33 million people worldwide have tested positive for COVID-19. [1] Could fitness trackers and smartwatches be used for the early detection of COVID-19 and help prevent its spread? More data is needed to know for sure, but it’s possible that a fitness tracker or smartwatch could pick up on temperature, heart rate, and/or respiratory rate changes before you notice a change or have symptoms of COVID-19. [2]

The ECG on Your Wrist

COVID-19 has shown us that having the option for testing from home is an area that’s becoming more and more useful. One day we may all have a mini-medical office at home. Consider all the people who have bought home pulse oximeters this year to measure their oxygen levels because of COVID-19.

How Do Wristband Generated ECGs Work?

The gold standard for ECGs is a 12-lead ECG, which is what’s done at the doctor’s office or hospital. There are now fitness tracker and smartwatch options that can take a 1-lead ECG for you wherever you are. The wristband of your device in theory could be moved around your body to produce a multi-lead or 12-lead ECG, but so far there isn’t enough data to say that this is equivalent to a standard 12-lead ECG.

Are Wristband Generated ECGs Helpful?

Although there have been many cardiac complications associated with COVID-19 [6], so far there hasn’t been strong data that ECGs from wristband fitness trackers or smartwatches are useful for COVID-19. However there are other potential scenarios where fitness tracker or smartwatch ECGs could be useful to you.

Why is Atrial Fibrillation Important?

Having atrial fibrillation can lead to the formation of blood clots in your body, which can cause a stroke, among other things. Generally speaking the risk of stroke with AF is greater for people who are over 60 years old and/or people with underlying medical conditions like diabetes and high blood pressure.

The Accuracy of Wristband Fitness Trackers and Smartwatches

This review is based on the data available, really more data is needed as a lot of the data isn’t the highest quality data. Some studies were funded by the company making the wearable device, so there could be bias because of that. Also some studies were done in free living conditions (normal everyday life) versus others that were done in Electrophysiology Labs where heart rhythms or heart rates were artificially induced. It could make a difference in how useful the data is if heart rhythms or heart rates are naturally occurring versus induced for the purpose of a medical study.

The Accuracy for the Diagnosis of AF

Wristband fitness trackers and smartwatches have been shown to be accurate in detecting atrial fibrillation in some large studies.[16, 17, 18] However more people are also likely to get a notification that they have an irregular pulse, but don’t actually have atrial fibrillation on subsequent testing. [19] Compared to a traditional 12-lead ECG there is some sensitivity and specificity loss with wristband fitness tracker and smartwatch ECGs [20].

People Who Have a History of AF

Wristband fitness trackers and smartwatches may have difficulty determining what a person’s heart rate is when they are in atrial fibrillation. [21, 22] For people with a history of atrial fibrillation this information can be important to their healthcare providers to determine how to adjust their medications for atrial fibrillation. So wristband fitness trackers and smartwatches may be less useful to a person who has a known history of permanent atrial fibrillation for managing their atrial fibrillation.

The Diagnosis of Non-AF Heart Disease

There are many future uses for wristband fitness trackers and smartwatch ECGs as their capabilities improve. Wristband fitness tracker and smartwatch ECGs could eventually be used to identify when people are having a myocardial infarction (heart attack) [23] and ischemic changes (not enough blood flow in the heart arteries) [24]. Moving the Apple Watch to different parts of your body to get a multi-lead or 12-lead ECG may be a promising option in the future to help with diagnosing heart attacks and abnormal heart rhythms. [25, 26]

Should You Buy A Wristband Fitness Tracker or Smartwatch?

For COVID-19, in my opinion, it’s possible it could help in early detection, although there’s very limited data showing this so far. But there are many ongoing studies, like the FitBit COVID-19 study, as well as the study the Department of Defense is conducting on commonly used wearables. We’ll have to wait and see what the outcomes are from these studies.

  1. Continuous temperature monitoring by a wearable device for early detection of febrile events in the SARS-CoV-2 outbreak in Taiwan, 2020
  2. Pew Research Center: About one-in-five Americans use a smart watch or fitness tracker
  3. Multichannel ECG recording from waist using textile sensors
  4. Cryptogenic stroke and underlying atrial fibrillation
  5. The COVID-19 Pandemic and Cardiovascular Complications
  6. Atrial fibrillation as an independent risk factor for stroke: the Framingham Study
  7. Estimated prevalence of undiagnosed atrial fibrillation in the United States
  8. Subclinical atrial fibrillation and the risk of stroke
  9. Reliability of Zephyr Bioharness and Fitbit Charge Measures
  10. Validation of a Self-Monitoring Tool for Use in Exercise Therapy
  11. Fitbit Charge HR Wireless Heart Rate Monitor: Validation Study Conducted Under Free-Living Conditions
  12. Heart rate measures from the Apple Watch, Fitbit Charge HR 2, and electrocardiogram across different exercise intensities
  13. Pilot Study Assessing the Influence of Skin Type on the Heart Rate Measurements Obtained by Photoplethysmography with the Apple Watch
  14. How consumer physical activity monitors could transform human physiology research
  15. Smartwatch Performance for the Detection and Quantification of Atrial Fibrillation
  16. Smartwatch Algorithm for Automated Detection of Atrial Fibrillation
  17. Using Apple Watch for Arrhythmia Detection December 2018
  18. Large-Scale Assessment of a Smartwatch to Identify Atrial Fibrillation
  19. Passive Detection of Atrial Fibrillation Using a Commercially Available Smartwatch
  20. Smart watches for heart rate assessment in atrial arrhythmias
  21. Accuracy of wrist-worn heart rate monitors for rate control assessment in atrial fibrillation
  22. Novel Use of Apple Watch 4 to Obtain 3-Lead Electrocardiogram and Detect Cardiac Ischemia
  23. Apple Watch detecting coronary ischaemia during chest pain episodes or an apple a day may keep myocardial infarction away
  24. Recording of Bipolar Multichannel ECGs by a Smartwatch: Modern ECG Diagnostic 100 Years after Einthoven
  25. Single-Lead ECG Recordings Including Einthoven and Wilson Leads by a Smartwatch: A New Era of Patient Directed Early ECG Differential Diagnosis of Cardiac Diseases?
  26. AVNRT captured by Apple Watch Series 4: Can the Apple watch be used as an event monitor?
  27. Apple Watch detecting high-grade block after transcatheter aortic valve implantation
  28. Smart watch recording of ventricular tachycardia: Case study
  29. Validating QT-Interval Measurement Using the Apple Watch ECG to Enable Remote Monitoring During the COVID-19 Pandemic
  30. CDC Prevention Programs
  31. Estimates of current and future incidence and prevalence of atrial fibrillation in the US adult population
  32. What is Atrial Fibrillation (AFib or AF)?
  33. Heart Disease and Stroke Statistics — 2019 Update: A Report From the American Heart Association

I’m a cardiologist, consulting and providing advisory services in health tech.