Biorhythm is a free lifestyle app developed by Shimada System for Android devices. The app allows users to track their physical, sensitivity, and intellectual cycles through a simple and easy-to-use interface.

The app displays a graph that showcases the different cycles, with physical cycles lasting 23 days, sensitivity cycles lasting 28 days, and intellectual cycles lasting 33 days. Users can also view an original cycle, which displays periods longer than one day. The app features a yellow line that indicates the current date, which can be changed by sliding the graph.

Users can also set their date of birth in the app's menu to access a birthday feature. Additionally, the app allows users to view their original cycle, which hides the display of cycles for 0 days. Overall, Biorhythm is a simple and effective app for tracking and monitoring physical, sensitivity, and intellectual cycles in one's daily life.