HIIT timer. Hard, rest, repeat.

Short bursts of hard work with recovery in between, set up once and run start to finish by voice. Warm-up, work, rest, rounds, round recovery and cooldown: Intervals One handles every one of them.

Free to set up and run. Different times for each move, presets and move names come with Pro.
40s
A common work interval
20s
And its rest
6
Stages the app runs for you
0
Times you touch the phone mid-round

What is HIIT?

HIIT, or high-intensity interval training, alternates short periods of hard effort with periods of recovery. The recovery is what lets you go hard again, so each work interval can be tougher than anything you could keep up continuously.

The split between work and rest is up to you, and it's the main thing to adjust as you get fitter. Common choices are 30 seconds on and 30 off, 40 on and 20 off, or 45 on and 15 off. If you're new to it, start with as much rest as work, or more.

A session usually strings several moves into a round, repeats the round a few times with a longer recovery between rounds, and finishes with a cooldown. Tabata is one particular kind of HIIT, with a fixed 20 seconds on and 10 off.

Set it up in under a minute

The free Simple screen covers most HIIT sessions. These numbers give a 40/20 workout of four moves, three times through.

Warm Up03:00
Your choice
Work Time00:40
Rest Time00:20
Exercises4
Moves per round
Rounds3
Round Recovery01:00
Between rounds
  1. Open SimpleIt's the first tab on the dashboard, and it's free.
  2. Set your work and restEvery move in the round uses the same split. The app puts a rest between moves, then a round recovery at the end of each round.
  3. Set Exercises, Rounds and Round RecoveryFour moves at 40/20, three rounds and a minute between rounds is about 13 minutes, plus warm-up.
  4. Add a cooldown in settings, then press StartThe app announces every stage and how long it lasts, says "Halfway there" and counts down the last three seconds.

Want a different time for each move? The Advanced builder (Pro) gives every move its own work and rest. Pro also includes ready-made presets at every level, from Pure Bodyweight Beginner to Explosive Bodyweight.

Three HIIT workouts to try

Work hard but keep your form. If it falls apart, slow down or take a longer rest.

Starting outAbout 13 min + warm-up

30/30 bodyweight basics

Equal work and rest, four simple moves, three rounds. A good place to start, and to come back to on easy days.

Moves
Jumping jacks, squats, incline push-ups, plank
Set up
Simple: Work 00:30, Rest 00:30, Exercises 4, Rounds 3, Round Recovery 01:00
Needs
Free
Getting fitterAbout 18 min + warm-up

40/20 full body

Twice as much work as rest. Four moves that hit your legs, upper body and core in turn, four times through.

Moves
High knees, jump squats, push-ups, mountain climbers
Set up
Simple: Work 00:40, Rest 00:20, Exercises 4, Rounds 4, Round Recovery 01:00
Needs
Free
ExperiencedAbout 24 min + warm-up

Explosive bodyweight

Jumping and plyometric moves, each with its own work and rest time, five rounds. This is the Explosive Bodyweight preset.

Moves
Plyometric push-ups 30s, jumping lunges 40s, broad jumps 40s, tuck jumps 30s
Set up
Presets: Explosive Bodyweight. Or in Advanced: rests of 30s, 20s and 20s between moves, Rounds 5, Round Recovery 01:30
Needs
Pro, for presets and different times for each move

HIIT questions

What is HIIT?

High-intensity interval training: short periods of hard effort alternated with periods of rest or easy movement, repeated for several rounds.

What's a good work and rest split for beginners?

Start with as much rest as work, like 30 seconds on and 30 off, or even more rest than work. As you get fitter, shift towards 40/20 or 45/15.

How long should a HIIT workout be?

The intervals themselves often take 10 to 25 minutes, plus a warm-up and cooldown. Intervals One shows the total time as you build the workout, so you know before you start.

Is Tabata the same as HIIT?

Tabata is one specific kind of HIIT: 20 seconds on, 10 seconds off, eight rounds. HIIT covers any split, any number of moves and any number of rounds.

Can I do HIIT with the free version?

Yes. The free Simple screen gives you warm-up, work, rest, exercises, rounds, round recovery and cooldown, with voice or beep cues. Pro adds the Advanced builder for a different time on each move, ready-made presets and move names.

More ways to train

Set it once. Then just work.

Download Intervals One, set your split and your rounds, and press start.