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Interval timing for HIIT workouts

High-intensity interval training lives and dies by timing. Here is how to structure your work and rest intervals, with or without a gym timer.

Standard intervals

Classic HIIT uses 30 seconds of work and 30 seconds of rest, or 40/20 for a harder variant. Beginners should start with 20 seconds of work and 40 seconds of rest.

Why timing matters

The intensity of HIIT comes from knowing the rest is short and finite. Guessing intervals destroys that structure; a visible countdown keeps effort honest.

Structure a session

Warm up for 5 minutes, then 8 to 12 rounds of your work/rest interval, then cool down. One round of 30/30 for 10 rounds is a 10-minute session, plus warm-up.

Tools

A stopwatch with laps works, but a timer with audible alerts is better; our free online timer can be set to any interval and alerts even in a background tab.