Health apps: what happens to your data?
A health app may store symptoms, sleep, menstrual-cycle dates, location and information from a connected device. The data it collects and shares depends on the app and your settings. Before entering sensitive information, check who operates the service, what permissions it needs and how to delete your account and request information about retained data.
What health apps may collect
A health app gathers data from several directions at once, and it holds more than you might expect.
- What the user types. The user enters age, sex, weight, symptoms, mood, medicines, cycle dates, sleep hours and the food they ate, all by hand, and each one is personal data.
- What the phone senses. The motion sensors give steps and activity. Location gives where a person sleeps, works and exercises. The microphone and camera, if you allow them, give sound and images.
- What a connected watch or scale sends. Heart rate, sleep, blood oxygen and weight arrive in a steady stream, and the app stores them alongside the rest.
- What the app infers. From cycle dates the app can estimate a likely pregnancy. From mood entries it can build a picture of mental health. These inferences are also data, and they can be more sensitive than the entries that produced them.
- Advertising and analytics. Some apps use third-party software to analyse usage or serve advertising. The data it receives varies. Check the policy rather than assuming either that the app shares all health entries or that an advertising identifier is harmless.
A cycle-tracking app illustrates the point. The user enters a date, and the app now holds a guess about fertility, contraception and pregnancy.
Where app data may be stored or shared
Some apps keep information on the phone, while others upload it to servers in Singapore or overseas. Read the storage and sharing policy for the app you use. Third-party analytics, research partners or service providers may be involved. The policy should describe their access, so look for it there rather than assuming.
Analytics and advertising services embedded in the app receive some of it, sometimes in a form that still identifies the user. The terms often allow sharing with "partners" and "affiliates", which are words that can cover a great deal. Some companies sell aggregated or "anonymised" data to researchers or data brokers, and anyone who combines anonymised health data with other records can sometimes link it back to a person. If another company buys the business, in most cases the data goes with it under the new owner's terms.
All of this may be proper, and the privacy policy discloses much of it. But the policy is long, the language is broad, and you gave your consent with a single tap. The confidentiality that applies to a medical record does not apply to a mood diary held by a software company.
How Singapore’s data protection rules apply
Singapore’s PDPA sets obligations for organisations handling personal data, including notification of purposes, appropriate consent or another permitted basis, security, access and correction, retention limits and safeguards for overseas transfers. The PDPA has exceptions and conditions; it does not promise that an organisation will delete all information on request. Public agencies are subject to a separate public-sector framework.
Public health services and private apps
HealthHub, Healthier SG and Healthy 365 serve different public-health purposes and have their own terms, data flows and controls. HealthHub provides access to selected health records and services. Do not assume that a National Steps Challenge record becomes part of your national clinical record by default or that a doctor monitors it.
Private apps use different business models, including subscriptions, advertising and partnerships. A paid app can still share data, and a free app may not sell it. Ask what the policy permits and what controls you have.
A tracking record can be useful to bring to an appointment, but linking an app to another service does not by itself mean a clinician will review it. Before enabling a connection, check what the app shares, with whom and for what purpose.
Checking permissions and deleting accounts
Review permissions before granting them and again in the phone’s settings. A basic step counter may need motion data, while a route-tracking feature may need location. Turn on precise location or background access only if the feature you want uses it. Available controls differ by app and phone.
In most cases, removing an app does not close the account or erase server-held data. Use the account-deletion process and check what the operator will delete, what it may retain for legal or legitimate business needs, and whether subscriptions need separate cancellation. Contact the operator’s data-protection contact if the process is unclear.
A short checklist before installing helps.
- The maker is named. A company that publishes its address is easier to hold to account.
- The business model is clear. A subscription, a one-off price or advertising each explains what the data is for.
- The permissions match the job. If a step counter asks for the microphone, find out why.
- The account can be deleted from inside the app. If that is not clear, it is safer to assume the data stays.
- The job actually needs an app. A notebook, or HealthHub, covers a good deal.
Choosing an app with enough information
Choose an app for a clear purpose and review its operator, permissions, sharing and retention terms. Enter only the information you need to use that service. Public-health apps also have specific functions; check whether a feature sends information to your care team rather than assuming it does.
A tracking app is also a poor place to leave a worrying pattern. A mood diary that has read low for weeks, a cycle that has become irregular or very heavy, or a sleep app that shows months of short nights are each a reason to book a polyclinic or GP appointment and bring the record along. The app can describe the pattern, and a doctor can examine, ask the questions the app did not, and decide what it means. If you have thoughts of suicide or self-harm, reach a person now. Call Samaritans of Singapore on 1767 or national mindline on 1771. If you cannot stay safe or there is immediate danger, call 995 or go to an emergency department.
A practical next step
Give an app only the permissions its features need. Read its privacy and retention policy before adding sensitive records. In most cases, deleting the app from your phone does not delete your account or the data its operator holds.
Sources and further reading
These references explain the guidance and research discussed above. For advice about your own health, speak to a qualified healthcare professional.
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