Key takeaways
- HIIT alternates short bursts of hard effort with easier recovery periods.
- It's time-efficient and improves fitness, but it doesn't burn chest fat specifically and isn't essential for fat loss.
- Beginners should start with low-impact intervals, such as cycling or brisk uphill walking, once or twice a week.
- Check with a doctor first if you have heart problems, high blood pressure or haven't exercised for a long time.
In this guide
High-intensity interval training, or HIIT, is often promoted as the fastest way to burn fat. Short, intense workouts that promise big results in 20 minutes sound perfect for busy men. But HIIT is also demanding, easy to overdo, and not the magic fat-loss solution it's sometimes made out to be.
This guide explains what HIIT is, what it can and can't do, how to start safely, and how to fit it alongside strength training and walking.
What is HIIT?
HIIT alternates short periods of hard effort with periods of easier recovery. For example, 30 seconds of fast cycling followed by 90 seconds of easy pedalling, repeated several times.
"Hard" is relative to your fitness. For a beginner, a brisk uphill walk might be a hard interval. For a fitter person, it might be sprinting.
A simple way to judge effort is a 1 to 10 scale:
| Effort | Feels like |
|---|---|
| 3–4 | Easy; you can hold a full conversation |
| 5–6 | Moderate; you can talk in short sentences |
| 7–8 | Hard; you can only say a few words |
| 9–10 | Very hard to maximal; not suitable for beginners |
Beginner intervals should sit around 7 out of 10, not all-out.
What HIIT can do
- Improve cardiovascular fitness in a short amount of time.
- Fit into a busy schedule, with sessions often lasting 15 to 25 minutes including warm-up.
- Count towards activity guidelines. Health guidance, such as the World Health Organization's, counts vigorous activity towards your weekly total, with each minute of vigorous activity worth roughly two minutes of moderate activity.
What HIIT can't do
- Burn chest or belly fat specifically. Fat loss happens across your whole body. Why you can't spot-reduce chest fat explains why.
- Replace a calorie deficit. Research comparing HIIT with steady cardio generally finds similar fat loss when total effort is similar. Neither works well without a sensible diet.
- Replace strength training. Strength training builds and keeps the muscle that shapes your chest. Cardio vs weights for fat loss explains how they compare.
Before you start
Build a base first. If you're new to exercise, spend a few weeks walking regularly and doing basic strength training before adding intervals. Walking for fat loss is a great starting point.
Choose low-impact options
Jumping-based HIIT, such as burpees and jump squats, is hard on the knees, ankles and back, especially if you're heavier or new to training. Low-impact options are safer and just as effective for fitness:
- Exercise bike or spin bike
- Rowing machine
- Brisk uphill walking or incline walking on a treadmill
- Swimming
- Cross trainer (elliptical)
Three beginner HIIT sessions
Always start with 5 minutes of easy warm-up and finish with 5 minutes of easy cool-down.
Session 1: Gentle intervals (weeks 1–2)
| Interval | Effort | Time |
|---|---|---|
| Hard | 6–7 out of 10 | 20 seconds |
| Easy | 3–4 out of 10 | 100 seconds |
| Repeat | 5 times |
Session 2: Building up (weeks 3–4)
| Interval | Effort | Time |
|---|---|---|
| Hard | 7 out of 10 | 30 seconds |
| Easy | 3–4 out of 10 | 90 seconds |
| Repeat | 6 times |
Session 3: Hill walking intervals
Find a moderate hill or use a treadmill incline. Walk briskly uphill for 60 seconds at about 7 out of 10, then walk slowly back down or lower the incline for 2 minutes. Repeat 5 or 6 times.
Progress slowly: add one interval, or 5 to 10 seconds to the hard part, every week or two, only if you're recovering well.
How HIIT fits into your week
| Day | Activity |
|---|---|
| Monday | Strength training |
| Tuesday | Walk 30–45 minutes |
| Wednesday | Strength training |
| Thursday | Short HIIT session, 20 minutes |
| Friday | Strength training |
| Weekend | Long walk or activity you enjoy |
- One or two HIIT sessions a week is plenty.
- Avoid HIIT the day before heavy leg training if it leaves your legs tired.
- Keep walking as your main daily activity. It's easier to recover from and adds up over the week.
Signs you're overdoing it
- Persistent fatigue or poor sleep
- Strength falling in the gym
- Joint pain, especially knees or back
- Dreading every session
If you notice these, cut back to one session a week or replace HIIT with extra walking. Recovery basics explains how to tell whether you're recovering well.
Common mistakes
- Going all-out from the start. Beginners should work at about 7 out of 10.
- Too many sessions. More isn't better with HIIT.
- Jumping-based workouts before you have a fitness and strength base.
- Skipping the warm-up and cool-down.
- Using HIIT to "earn" food or compensate for overeating.
The bottom line
HIIT is a time-efficient way to improve fitness, but it isn't a fat-burning shortcut and it isn't essential. If you enjoy it, start with low-impact intervals once or twice a week at a hard-but-manageable effort, alongside strength training and daily walking. Check with a doctor first if you have heart or blood pressure concerns, and stop immediately if you feel unwell.
Free printable resource
Put this into practice: the free 7-day starter checklist
Seven practical days covering your baseline, nutrition setup, a simple beginner workout, daily movement and a review. It comes with a grocery checklist, habit tracker, progress sheet and a planner for the next 30 days.
Free, printable and no sign-up needed right now.
How this guide was written
Written by the LoseManBoobs7 editorial team using established public-health guidance and peer-reviewed research, following our editorial policy and health content policy. It has not been individually reviewed by a medical professional. Last reviewed . Spotted an error? Tell us.