What wearables record
Fitness trackers and smartwatches are packed with sensors. Depending on the model, they may record steps, heart rate, sleep patterns, workouts, location from GPS, skin temperature, blood oxygen estimates, and other measurements. Apps often add information you enter yourself, such as weight, medications, menstrual cycle details, meals or mood.
On their own, individual readings can seem trivial. Combined over weeks and months they can reveal a great deal: when you wake, where you exercise, your usual routes, how active you are and, in some cases, hints about your health. That is why it is worth knowing who can see them.
This article is general information and not medical advice. Readings from consumer gadgets are estimates and should not be treated as a diagnosis. Talk to a qualified health professional about any health concern.
Who may see the data
You and your devices. Data usually syncs between the wearable, your phone and an online account.
The manufacturer. Most companies store your data on their servers to power the app, back it up and provide features. Check how long it is kept and whether you can delete it.
Other apps you connect. Many trackers can share with other services, such as a running app, a nutrition tracker, a sleep program or an insurer’s or employer’s wellness program. Each connection gives that service some access, governed by its own policy.
Other people in the app. Social features may let friends or followers see your workouts, routes and achievements. Some defaults are public.
Advertisers and analytics partners. Some apps share data with partners for advertising or product analysis. The extent varies, and the privacy policy is where to check.
Employers or insurers, if you opt in. Some workplace and insurance programs invite you to share activity data in exchange for incentives. Joining is a choice. Read what is shared and how it may be used before agreeing.
Authorities, in limited cases. Companies may be required to provide data in response to valid legal requests. Rules differ by country.
Health-related data is treated as sensitive in many places, and some regions give it extra legal protection, but the protections depend on the type of service and where you live. Do not assume the data is covered by medical privacy rules just because it concerns health.
Review the sharing settings
Open your tracker’s app and look under privacy, sharing, account, data or connected apps. Items worth checking:
- Profile visibility. Is your profile public, visible to friends only, or private? Choose the narrowest option that still works for you.
- Activity feeds. Decide whether workouts are posted automatically, and who can see them.
- Connected services. Review the list of apps and services linked to your account and remove any you do not use. The same habits apply as for third-party apps connected to social accounts: each link is another place your data lives.
- Wellness programs. Check what an employer or insurer program can see, and whether you can stop sharing.
- Data for research or product improvement. Many apps offer opt-in or opt-out choices. Read the description and decide.
- Marketing and advertising choices. Turn off personalized advertising if the option exists.
Location is the sensitive part
Location data deserves special attention. Maps of your runs or walks can show where you live, where you work and when you are away from home. Because routes tend to start and end at the same places, they can point to your front door.
- Hide or trim the start and end of routes using privacy zones around your home and workplace, if the app offers them.
- Set activity maps to private or friends-only.
- Consider whether live-tracking or “share my location” features need to be on, and with whom.
- Turn off GPS recording for activities where you don’t need a map.
- If you post workout summaries elsewhere, remember that they can reveal patterns; the article on what your posts reveal about your routine explains the wider issue, and photos carry hidden details too, as discussed under photo location data.
On the phone itself, review the app permissions granted to the companion app. Location, contacts, Bluetooth and notifications may be requested; allow what the tracker needs and nothing more. Choosing “only while using the app” for location, where available, often strikes a good balance.
Secure the account
A fitness account may contain years of personal history. Use a unique password, preferably kept in a password manager, and turn on two-step sign-in if it is offered. If the account is breached, health and location history could be exposed. You can also check whether your email has been in a known leak by following the guidance on breach exposure checks.
Keep the tracker and app updated, too. Updates can fix security issues and change privacy options, so it is worth skimming the release notes occasionally.
Delete and move on
When you stop using a tracker, simply discarding it does not delete your history. Export the data you want to keep, delete the history or the account if you want it gone, remove linked apps, unpair the device and factory-reset it. Check the maker’s instructions, because deleting an account may be permanent. If you give or sell the tracker, the steps in the article on smart device resets apply.