Written by Nikita Revin, developer of Tonus. Updated 13 October 2026 for the publicly available version 1.4.
What works without a connection
Tonus stores workout plans, written exercise instructions and workout history on the iPhone. You can use the plans and written instructions without internet access. Apple Health integration is optional, and the app says that workout history and Health data stay on the device.
Why a video may still need internet
A video shown in the exercise library can be streamed or opened through an external provider. Online playback needs a connection. External RUTUBE and YouTube pages open at your request, use their own policies and may display ads. An offline plan does not mean every video is available offline.
Prepare supported clips before going offline
Supported clips can be downloaded and later removed in Profile. Download them while connected and check that the clips you need are available before leaving the connection. This feature does not mean that every external video can be downloaded.
What sharing changes
You can choose to share a workout result or an aggregate usage report. The published description says that the usage report contains no Health data or identifiers. Sharing is a separate choice from keeping a local workout history. If you open an external video service, that service handles its own requests.
What to check on a new phone
Device storage does not itself promise automatic synchronization across phones. Before changing or resetting your iPhone, check your normal backup and transfer options. Keep this distinction in mind when comparing apps: offline access, local storage and synchronization are different features. Tonus 1.4 needs iOS 17 or later and works without an account or subscription.
Tonus does not provide medical care. Stop if you feel pain or unwell. If you have health restrictions, discuss training with a qualified professional.
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