HIIT, or high-intensity interval training, means short bursts of hard effort separated by periods of easier movement or rest. The idea is older than the name: runners have done repeats on tracks for a century. What makes HIIT difficult for beginners is not the format but the intensity. Most people either go far too hard on day one and quit sore, or never push past a jog and wonder why nothing changes. This plan takes four weeks to move you from walking intervals to a genuine HIIT session, with timer settings for every workout.
What "hard" should feel like
You do not need a heart-rate monitor. Two simple tests work well enough.
- The talk test. During a work interval you should be able to say a few words, but not a full sentence. If you can chat, go harder. If you cannot speak at all, you are sprinting, which is more than a beginner needs.
- RPE (rating of perceived exertion). Rate the effort from 1 (sitting still) to 10 (the hardest thing you could do). Work intervals in this plan sit at 6 to 7 in week one and reach 8 by week four. Rest intervals should drop you to 2 or 3: walking, not standing frozen.
Hard is relative. A brisk uphill walk is a work interval for someone who has not exercised in years. Nobody else can see your RPE, so be honest in both directions.
Before you start
Pick one or two exercises you can already do with decent form: brisk walking, cycling, marching with high knees, bodyweight squats, step-ups onto a low step, or rowing. Save burpees and jump squats for later. Every session below begins with 5 minutes of easy movement and ends with 3 to 5 minutes of walking and gentle stretching; see warm-up and cool-down for a routine. The timer settings cover only the interval block.
The 4-week plan
Do the interval session three times a week, with at least one day between sessions. Set the interval timer with the work, rest and rounds listed. All times are in seconds.
Week 1: learn the rhythm
- Settings: work 30, rest 60, rounds 8 (12 minutes). Or open the 30/30 timer and change rest to 60.
- Effort: RPE 6. You should finish thinking you could do more.
- Sample: fast walking or easy cycling for the work, slow walking for the rest.
The goal this week is to get used to the beeps and the change of pace, not to get tired.
Week 2: shorten the rest
- Settings: work 30, rest 45, rounds 10 (12.5 minutes).
- Effort: RPE 6 to 7.
- Sample: alternate rounds of bodyweight squats and marching with high knees.
Week 3: equal work and rest
- Settings: work 30, rest 30, rounds 12 (12 minutes). This is the 30/30 preset with the rounds raised.
- Effort: RPE 7. A few words at a time.
- Sample: rotate three moves: step-ups, squats, mountain climbers at a controlled pace.
Week 4: your first real HIIT session
- Settings: work 40, rest 20, rounds 10 (10 minutes), the timer's default.
- Effort: RPE 8 on the work intervals. The last three rounds should feel genuinely hard.
- Sample: squat to stand, fast feet, push-ups on a bench, reverse lunges, cycling or rowing sprint. Two passes through the five moves.
If any week feels too easy, repeat it at a higher RPE rather than skipping ahead. If a week feels too hard, repeat it at the same settings. Taking six weeks instead of four changes nothing about the result.
What to do on off days
Off days are not rest from all movement. Walk, cycle gently, do mobility work, or do a light strength session. The WHO's 2020 guidelines suggest 150 to 300 minutes of moderate activity per week, and three 12-minute interval sessions cover only a small part of that. Easy movement on the other days makes up the difference and helps the legs feel normal again sooner. Some soreness after week one is expected; muscle soreness explains what is normal and what is not.
Common beginner mistakes
- Sprinting round one. The first interval sets the pace for the rest. Start at the effort you plan to hold in round eight.
- Stopping dead in the rest. Keep walking. Standing still right after hard effort makes the next round feel worse.
- Adding sessions. Three a week is the plan. A fourth does not speed things up; it usually just produces a missed week later.
- Changing everything at once. Change one variable per week: work time, rest time, rounds or effort.
Warning signs: stop the session
Pushing through tiredness is part of HIIT. Pushing through the following is not.
- Chest pain or pressure, or pain spreading to the arm, jaw or back.
- Dizziness, light-headedness or feeling faint.
- Nausea that does not pass within a minute of easy walking.
- Sharp joint pain, as opposed to the dull burn of working muscles.
- Breathing that does not settle after two or three minutes of rest.
If any of these happen, stop, walk slowly, and if it does not pass quickly, get medical help. If you have a heart condition, are pregnant, or have been inactive for a long time, check with a doctor before starting interval training.
After week 4
You now have a base. From here you can add rounds, try a 45/15 ratio, or move to a Tabata block; how to start working out covers building a full weekly routine around it. Keep the three-sessions-a-week rhythm, and keep logging your RPE so progress shows up in the numbers.
This article is general information, not medical advice.