Interval timer (HIIT)

What it's for

For high-intensity interval workouts (HIIT, Tabata, circuits): keep your hands free and follow the timer, which beeps when to switch phase.

How to use it

Set prep, work, rest and rounds, then press Start. Classic Tabata is 20 s work and 10 s rest for 8 rounds.

Where Tabata comes from, and why hardly anyone does it

The protocol comes from a Japanese study of 1996 on speed skaters: twenty seconds of work and ten of rest, eight times, for a total of four minutes. The point lost in popularisation is that those twenty seconds were at an intensity close to 170% of VO2max, that is an effort that becomes unsustainable after the sixth round.

What is commonly called «tabata» in a gym, that is four minutes of bodyweight exercises, has the same time structure and a completely different intensity: it is a good circuit, but it is not the protocol of the study and does not give those results. That is not a flaw, it is just a name used for something else.

The work-to-rest ratio says what you are training

A 1:1 ratio or more rest than work trains power: the pauses exist so that you can genuinely go hard again every time, and if they are shortened the intensity drops and the session changes nature. A 2:1 or 3:1 ratio in favour of work trains the ability to tolerate fatigue, and that is what circuits do.

The commonest mistake is keeping the pauses too short in the belief that it means training more: what happens is that every round is slower than the last, and in the end you have done a medium-long piece of work instead of an intense one. If the rounds visibly slow down, the rest is too short.

Why a sound cue is needed and not a watch

During an intense effort you cannot look at a stopwatch: vision blurs, the phone is on the floor and counting in your head is impossible. A beep frees the attention, which is exactly what is needed in order to push.

It is worth setting a preparation period of ten or fifteen seconds before the first round: it is for getting into position, and without it you always start late or badly. And a second, different cue for the end of the last round: knowing it is over changes how the final minute is approached.

The safety rules that apply to everyone

Interval training is intense by definition: anyone who has not trained for some time, who has heart or blood pressure problems, or who has no recent medical clearance, should begin with continuous moderate work. That is not a ritual formula: intervals take the heart rate close to maximum, and it is the kind of effort under which problems show themselves.

Then three obvious things apply: warm up properly first, because the first round is the one you get hurt in; choose exercises you can perform with clean technique even when tired, because fatigue makes everything worse; and do not do intense intervals every day, because the benefit arrives in the recovery and not in the session.

Nearby tools

For continuous timing there is Online timer and for rhythm Metronome. On the training side Heart rate zones, Calories burned and One-rep max calculator.