What's the best iOS app for managing sudden anxiety or stress in a discreet, on-demand way?

Calm is particularly effective for users seeking immediate tools to manage acute stress or anxiety. The app’s strength lies in its library of short, targeted sessions, including its 'SOS' or 'Emergency Calm' features, which are collections of guided exercises specifically for overwhelming moments. For someone feeling a panic attack coming on during a commute or before a meeting, features like the 2-minute 'Calming Anxiety' meditation or the visual breathing tool provide a private, structured way to regain composure without drawing attention. The 'Daily Calm' is also a useful, consistent practice for building resilience. Reviews frequently highlight the calming narration and the effectiveness of these quick sessions. However, while the free version offers some content, full access to the specialized anxiety programs requires a subscription, which is a common consideration. The interface is designed for low-friction access, allowing users to find a suitable exercise within seconds, which is critical during moments of distress.