Press one and it is loaded
- Tabata Timer8 × 0:20 / 0:10Seven to eight sets of twenty seconds with ten of rest between them, handed over whole by the 1996 paper.Medicine & Science in Sports & Exercise
- HIIT Timer8 × 0:40 / 0:20LoadedForty hard and twenty easy, eight times over: a gym circuit format for near-maximal work, with time to reach the next station.
- EMOM Timer10 × 1:00A cue once a minute and no scheduled recovery, so you earn your rest by finishing the repetitions early.CrossFit
- Rest Timer1 × 2:00Two minutes of rest, started as you rack the bar: the top of the ACSM range for muscle growth and the NSCA floor for big lifts.American College of Sports Medicine · National Strength and Conditioning Association
- Plank Timer3 × 0:30 / 0:30Three holds of thirty seconds with thirty between them, the front plank in the USA Gymnastics exercise progression sheet.USA Gymnastics
- CrossFit Timer1 × 20:00One twenty minute clock with no rounds and no rest inside it, the length the published benchmark Cindy is scored over.CrossFit
- Stretching Timer10 × 0:30 / 0:10Thirty second holds taken twice a muscle group, which is the sixty seconds the ACSM position stand asks for.American College of Sports Medicine
What interval training did for VO2max across 28 studies
A 2015 meta-analysis pooled 28 controlled trials with 723 healthy adults aged 18 to 45. High-intensity interval training raised their VO2max, the most oxygen the body can use, by 5.5 ml/kg/min against people who did not train. Steady endurance training raised it by 4.9. Set against each other, the intervals came out ahead by a small 1.2 ml/kg/min. The gains were larger for people who started less fit and for programmes that ran longer.
Sports MedicineMilanović, Sporiš and Weston, 2015, Sports Med 45(10):1469 to 1481, PMID 26243014
It can also take little time. In a 2006 McMaster study, 16 active men trained six times in two weeks: half did 4 to 6 all-out sprints of 30 seconds on a bike, half rode steadily for 90 to 120 minutes. The sprint group spent about 2.5 hours in all against 10.5, and both groups improved their cycling time trials, with no difference between the groups. In a 2005 study from the same lab, six such sessions doubled how long eight people could ride at a hard pace, from 26 to 51 minutes.
The Journal of PhysiologyGibala et al., 2006, J Physiol 575(3):901 to 911, PMID 16825308Journal of Applied PhysiologyBurgomaster et al., 2005, J Appl Physiol 98(6):1985 to 1990, PMID 15705728
Those are gains in healthy young and middle-aged adults. Anyone with a heart condition, or who has not trained hard before, should check with a doctor first. If hard efforts are new to you, start with the beginner session below, which gives you more easy time than work.
The protocol
40 seconds hard, 20 easy, 8 rounds: 7:40 from the first effort to the last. 40/20 is a gym habit with no paper behind it, and the 8 is ours.
How hard: near your limit, but repeatable. You should be unable to hold a conversation, and round 8 should still look like round 1 in form, if not in speed.
A 2017 review splits the family in two. HIIT means near-maximal efforts like these. Sprint interval training means all-out efforts, harder than the pace at which your oxygen uptake peaks.
The Journal of PhysiologyMacInnis and Gibala, 2017, J Physiol 595(9):2915 to 2930, PMID 27748956
Sprints need far more recovery. In the 2006 study each 30 second sprint was followed by 4 minutes of rest or very light pedalling.
The Journal of PhysiologyGibala et al., 2006, J Physiol 575(3):901 to 911, PMID 16825308
This timer rings a bell as each effort starts and ends, warns ten seconds before each effort ends, has a fullscreen key, and keeps the screen awake where the browser allows; it is free and needs no account. Keep this tab in front, because a browser may pause the sound of a tab you cannot see.
Sessions to try
These are our suggestions. Where one follows a published source, that source is cited under it.
- Beginner
20 seconds on, 40 easy, 8 rounds, on a bike or with brisk step-ups. Move to 30/30 when the last round feels controlled, then to 40/20.
- Circuit
8 rounds of 40/20 through four stations twice: squats, push-ups, kettlebell swings, mountain climbers. Use the 20 seconds to reach the next station.
- Lab intervals
The McMaster practical model: 8 to 12 efforts of 60 seconds at about your peak power, with 75 seconds easy. In Edit intervals set Work to 1:00 and Rest to 1:15.
The Journal of PhysiologyLittle et al., 2010, J Physiol 588(6):1011 to 1022, PMID 20100740
- Sprints
4 to 6 all-out sprints of 30 seconds on a bike, each followed by 4 minutes of rest or very light pedalling. Set Work to 0:30, Rest to 4:00 and Rounds to 4 to start.
The Journal of PhysiologyGibala et al., 2006, J Physiol 575(3):901 to 911, PMID 16825308
Warm up first with 5 to 10 minutes of easy movement.
Common mistakes
Pacing the 40 seconds like a jog because 7 more are coming. Pick an effort you could hold for about a minute, and accept that the last rounds will be ugly.
Turning the 20 seconds into a full stop. Walk, shake out your arms, get set for the next effort.
Choosing moves that need fresh technique. Box jumps and heavy snatches get sloppy when you are tired; squats, step-ups and a bike hold up.
Going hard every day. The McMaster studies ran six sessions in two weeks, with a day or two of rest between them.
The Journal of PhysiologyGibala et al., 2006, J Physiol 575(3):901 to 911, PMID 16825308Journal of Applied PhysiologyBurgomaster et al., 2005, J Appl Physiol 98(6):1985 to 1990, PMID 15705728
Questions
Is 40/20 or 30/30 better?
Neither ratio has a study behind it as a rule. In the 2015 meta-analysis the work-to-rest ratio had no clear effect on VO2max gains against not training, and a small one in favour of more work against steady training. 30/30 gives you more recovery, so start there and move to 40/20 when the last round stops falling apart.
Sports MedicineMilanović, Sporiš and Weston, 2015, Sports Med 45(10):1469 to 1481, PMID 26243014
How many times a week should I do HIIT?
The McMaster studies used six sessions in two weeks, about three a week, with one or two days of rest between them. That is a fair place to start.
The Journal of PhysiologyGibala et al., 2006, J Physiol 575(3):901 to 911, PMID 16825308Journal of Applied PhysiologyBurgomaster et al., 2005, J Appl Physiol 98(6):1985 to 1990, PMID 15705728
Six palettes, and a phase keeps its meaning in all of them
The same four grounds, drawn six ways. Each is solved so that get ready, work, rest and done stay apart, and so the clock stays readable from across a gym. Pick one and the whole page turns with it; this browser remembers the choice.
The app
The same clock, in your pocket
Bursta is being finished for phones. Android comes first and iPhone after it. It is the timer you have above, built as an app: the same reading of the wall clock every frame, so a locked screen, a phone call or a backgrounded app does not make it drift.
It keeps sounding with the screen off
The bell lands with the phone locked in your bag and your music still playing. A page in a tab cannot do that.
Your own workouts, and a record of them
A builder, a library you name and reorder, a history that fills itself in, and a calendar with repeats and reminders.
Made to be read while you are breathing hard
Six palettes, five text sizes, and the phase in the colour of the whole screen. English and Ukrainian.
Soon on Google PlaySoon on the App Store
