Authors : Ajay Chawda; Hardik Bait; Nirvan Bandal; Smith Chavan

Volume/Issue : Volume 11 - 2026, Issue 4 - April

Google Scholar : https://tinyurl.com/mhkdn2w5

Scribd : https://tinyurl.com/mr5244ke

DOI : https://doi.org/10.38124/ijisrt/26apr801

Note : A published paper may take 4-5 working days from the publication date to appear in PlumX Metrics, Semantic Scholar, and ResearchGate.

Abstract : We built FitPulse as a response to a straightforward problem: most fitness apps do one thing well but miss everything else. This paper walks through how we designed, built, and tested FitPulse — a mobile fitness tracking app that works on both Android and iOS from a single codebase using React Native and the Expo SDK. The app brings together real-time step counting through the phone's built-in motion sensor, a calorie and nutrition tracking engine based on the Mifflin-St Jeor formula, water intake logging, sleep history, and AI-suggested workout plans. To keep everything in sync across screens, we used React's Context API as a global state manager. User accounts are handled through Firebase Authentication, and all health data lives locally on the device using AsyncStorage — which means the app works just fine without internet. Across all the features we tested, the system hit 95.2% accuracy overall and held a steady 60 fps on both platforms.

Keywords : React Native, Expo SDK, Firebase Authentication, AsyncStorage, Pedometer, Mifflin-St Jeor, Cross-Platform, BMR, TDEE, Calorie Monitoring, Sleep Monitoring, Offline Fitness App.

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