About the Japanese Interval Walking Timer
A free, browser-based guided timer for the Japanese IWT protocol — alternating fast and slow walking intervals with audio cues and screen wake lock.
What it is
The Japanese Interval Walking Timer guides you through the interval walking training (IWT) protocol developed by researchers at Shinshu University, Japan. The method alternates periods of brisk, faster-paced walking with periods of slower, easier walking — the classic version being three minutes fast followed by three minutes slow, repeated five times for a 30-minute session.
The timer handles all the counting. Press start and it tells you when to speed up, when to slow down, how many sets you've completed, and how long you've been walking — so you can concentrate on your pace and your surroundings rather than watching a clock.
Everything runs in your browser. No data is sent to a server, stored, or logged anywhere.
The interval walking concept
Interval walking alternates between two effort levels within a single session. The fast phase raises your heart rate — you should be walking briskly but still able to speak in short sentences. The slow phase is a genuine recovery walk at a comfortable, conversational pace. This contrast is what makes the method distinct from a steady-pace walk.
The original research protocol uses three minutes at each pace, repeated five times. This timer defaults to that configuration but lets you adjust the duration of each interval and the number of sets to suit your fitness level or time available.
Key features
Audio cues via Web Audio API
At each phase transition the timer plays distinct audio signals — two short high beeps to signal fast walking, one lower sustained tone for slow walking, and a three-note ascending chime when the session ends. These use the Web Audio API so they play reliably even when the screen is locked or the tab is in the background.
Screen Wake Lock
On browsers that support the Screen Wake Lock API, the timer requests a wake lock when you press Start so the display stays on throughout your session. The lock is released when you pause, reset, or the session finishes. On unsupported browsers the timer still runs normally and audio cues still fire.
Adjustable intervals and sets
Change the fast interval, slow interval, and number of sets before starting. Settings accept decimal minutes (e.g. 2.5 for two and a half minutes) and any number of sets from 1 to 60. Settings lock while a session is running to prevent accidental changes.
Set and time tracking
The display shows the current phase (FAST WALK / SLOW WALK), the countdown for that interval, the current set out of the total, and the total elapsed time — updating every second throughout the session.
Who it's for
Beginners
The alternating structure makes it easier to sustain than continuous fast walking. Start with shorter fast intervals or fewer sets and build up gradually.
Regular walkers
Add structure to your daily walk. The timer does the thinking so you can follow the IWT protocol without counting minutes yourself.
People short on time
A standard session is 30 minutes. Reduce sets for a shorter workout — two sets give you 12 minutes of structured interval walking.
Older adults
The IWT method is widely used across age groups because the slow phase gives genuine recovery time between efforts. The audio cues mean you don't need to look at the screen.
A note on health advice
This tool provides general information and is not medical advice. Exercise intensity should match your own fitness and health. Please consult a physician before starting a new exercise routine or training at high intensity—especially if you have any heart condition, injury, or health concern.