# What Twikka does with your health data > Apps should ask your permission before they read data from Apple Health or Health Connect, and you choose what to allow. Who else sees your data depends on the app, so read what it says about sharing. You can take permission back later, but that may not delete data already collected. - Type: Guide - Topic: Technology & Tools › Wearables & Health Data - Reviewed by: Andrew Schox, BSc(Hons) PGradDipPod MPod, Podiatrist (2026-10-21) - URL: https://twikka.com/learn/what-twikka-does-with-your-health-data - Updated: 2026-10-21 - **Permission comes first:** apps ask before they read your health data, and you can allow some types of data and not others [1][2]. - **Who else sees it depends on the app:** some apps pass data to other companies, so read what an app says about sharing [1][3]. - **You can take permission back:** on Android you can revoke Health Connect access in its settings [2]. - **Switching off may not delete:** data an app has already collected can stay with it [3]. ## What does Twikka read from Apple Health or Health Connect? If you allow it, Twikka reads your steps and workouts from Apple Health (iPhone) or Health Connect (Android), and you can turn this off at any time in your phone's settings. What holds for any app is that it asks your permission first, and you decide what to allow. On an iPhone, Apple Health can show steps taken today, how often you move and how often you stand up [4]. With a smartwatch it can also track heart rate and sleep quality, and track activity all day rather than only when you carry the phone [4]. Apple gives separate permissions to separate sensors, so you can allow one kind of data and refuse another [1]. Some apps ask for very little. One walking app from a national health service makes syncing with Health Connect optional, reads only your step count and says it accesses no other health information [2]. Once you have given permission, an app can download and upload data without asking you again [5]. That is why it is worth reading which data types an app wants before you agree. Step count shows how much you move in a day, not how well you walk. It is also shaped by things like weather, appointments and opportunity to walk [6]. > **Try this:** Next time any app asks to connect to Apple Health or Health Connect, read the list of data types it wants. Allow only the ones you are comfortable sharing. ## Who can see your health data? It depends on the app, and health and fitness apps can pass data to other companies. Some companies share the data they collect with advertisers, insurance companies, employers and data brokers, and not all make this clear [1]. Some apps pass data to third parties that have their own policies, and leave you to decide about sharing yourself [3]. Apps also collect more than health numbers. Privacy policies can cover device identifiers, IP addresses, location and how you use the app, which can reveal things unrelated to health [1]. Many health apps need personal data before you can use them, and it may be used to personalise advertising. Most people are unlikely to know the full extent of what is collected [7]. You have some protection. Good practice for health apps includes encryption, secure sign-in and regular risk assessments. Under the EU's GDPR you have the right to access, amend, delete or restrict processing of your data [8]. People also say they want a clearer understanding of who else can access their health information and how to control that access [8]. What to do: - **Look for a plain explanation** of who your data is shared with, and whether you can choose what is shared. - **Check other companies' policies** if an app says it passes data on. - **Leave out health conditions** if an app doesn't need them. ## Can you disconnect your health data? Yes. You can take back an app's permission through the health permissions on your phone. In Health Connect on Android you can revoke access at any time in its settings [2]. Some apps can also be used without an account, in which case activity data stays on your device [2]. Disconnecting may stop only new data being collected. Data already shared can stay with the app or its affiliates, and some may still be used in anonymous form for research [3]. Deleting what has been collected can be slower: requests to delete personal information or close an account can be lengthy (an average of 30 days in some apps) and conditional, with no guidance on when data collection stops [3]. How easy it is varies from app to app. One app explained its deletion process clearly and aimed to remove all of a user's data within 30 days. Others gave no easy way to opt out of sharing or to delete an account from within the app [3]. In some apps the rights to ask for deletion or to object to the use of your data are not absolute, because continued use is sometimes necessary [2]. Before you rely on an app, check whether it explains how to delete your data and how long that takes. ## When to check with a health professional Follow your doctor's advice over anything an app suggests. Data from fitness devices and apps can be less reliable than data from approved medical devices, so treat it as a rough guide to your activity, not a medical measure [5]. If you're starting exercise after a long break, it's always a good idea to see your doctor first. For an injury or a health condition, see a health professional, such as your doctor or a physio. Call your local emergency number for chest pain or pressure (or pain spreading to the arm, neck, jaw or back, especially with sweating or feeling sick), severe breathlessness, fainting or collapse, signs of a stroke, a serious injury, or someone who isn't safe. ## Quick answers ### How do I change what an app can see later? Use the health permissions on your phone. In Health Connect on Android you can revoke access in its settings. Changing a permission stops the app reading new data, but it may not remove what the app has already collected, so check whether the app explains how to delete your data. ### What happens to my data if I stop using an app? It depends on the app. Some delete an inactive account after a set time; one national health service walking app does this one year after your last login. Others keep data already shared with their affiliates. Before relying on an app, check that it explains how to delete your data and how long that takes. ### How do I know if a health app is safe and not a scam? There is no single test, but some things are worth checking before you connect. Look for a plain explanation of who your data is shared with and whether you can choose what is shared. If the app passes data to other companies, check their policies too. Leave out health conditions if the app doesn't need them. ## Sources 1. Who is Benefiting from your Fitness Data? A Privacy Analysis of Smartwatches. University of Cambridge repository. https://api.repository.cam.ac.uk/server/api/core/bitstreams/6cf3c9ab-8468-49dc-a364-4037d71e8c7b/content 2. NHS (2026). Privacy policy for the NHS Active 10 app. https://www.nhs.uk/better-health/privacy-policy/privacy-policy-for-the-nhs-active-10-app/ 3. Kuntsman A, Miyake E, Martin S (2019). Re-thinking Digital Health: Data, Appisation and the (im)possibility of 'Opting out'. Digital Health. https://doi.org/10.1177/2055207619880671 4. Be Connected (eSafety). Monitoring your health on Apple iPhone. https://beconnected.esafety.gov.au/topic-library/health-wellbeing-technology-and-you/resources-to-help-achieve-your-health-goals/monitoring-your-health-on-apple-iphone 5. Gay V, Leijdekkers P (2015). Bringing Health and Fitness Data Together for Connected Health Care: Mobile Apps as Enablers of Interoperability. Journal of Medical Internet Research. https://doi.org/10.2196/jmir.5094 6. Li Z, Yamamura K (2026). Limitations of Generative AI for Numerical Aggregation of Apple Health Step Count Data: A Validation Study Using XML Records, Manual Calculation, and Health Auto Export. Advances in Neurology and Neuroscience. https://doi.org/10.33140/an.09.02.31 7. Taneski V, Schwarz P, Bošnjak L, Tropmann-Frick M, Brumen B (2026). Readability and vagueness of privacy policies in mHealth applications: a multi-country analysis. International Journal of Information Security. https://doi.org/10.1007/s10207-025-01203-z 8. Alhammad N, Alajlani M, Abd-Alrazaq A, Epiphaniou G, Arvanitis T (2024). Patients' Perspectives on the Data Confidentiality, Privacy, and Security of mHealth Apps: Systematic Review. Journal of Medical Internet Research. https://doi.org/10.2196/50715 --- Source: Twikka (https://twikka.com/learn/what-twikka-does-with-your-health-data). General information about physical activity, not medical advice.