HIIT in the UK: context and protocols
The Tabata protocol , 20 seconds of maximum effort followed by 10 seconds of rest, repeated 8 times for a total of 4 minutes , was developed by Professor Izumi Tabata at Ritsumeikan University, Japan, through research published in 1996. It became enormously popular in the UK thanks partly to Joe Wicks ("The Body Coach"), whose PE with Joe sessions during lockdown attracted millions of participants and put home HIIT on the mainstream map.
The NHS recommends at least 75 minutes of vigorous physical activity per week for adults , HIIT sessions count towards this target. For beginners, the NHS also suggests starting with shorter work periods and longer rest before building intensity.
Popular interval protocols
| Protocol | Work | Rest | Rounds | Total |
|---|---|---|---|---|
| Tabata | 20 s | 10 s | 8 | 4 min |
| HIIT classic | 30 s | 30 s | 10-20 | 10-20 min |
| HIIT 2:1 | 40 s | 20 s | 10-15 | 10-15 min |
| parkrun intervals (beginner) | 1 min run | 1 min walk | 10-15 | 20-30 min |
| Boxing rounds | 3 min | 1 min | 3-12 | 12-48 min |
What the science says
HIIT is more time-efficient than steady-state cardio for improving VO2 max and cardiovascular fitness. It also generates an EPOC (excess post-exercise oxygen consumption) effect , elevated calorie burn for 12-24 hours after the session. However, more is not always better: 2-3 HIIT sessions per week with adequate recovery is the evidence-based recommendation for most people.
Safety and limits
High-intensity intervals are demanding on the heart and joints. Start with a 1:2 work-to-rest ratio and build gradually. Consult a qualified healthcare professional before starting intense exercise if you have any cardiovascular conditions, joint problems, or have been inactive for a long period. This timer is a tool, not a substitute for personalised fitness guidance.
For stretching after your session, use the Stretching Timer.