Your First Interval Workouts: How Hard, How Long, How Often
Your first interval workouts should be harder than a steady jog or walk but nowhere near all-out: about a 7 out of 10, where you can say a few words but would not want to hold a conversation. Start with efforts of 30 to 60 seconds, rest at least as long as you worked, and do 4 to 6 rounds. Once a week is enough for the first month, twice a week after that, with at least a day between. The whole session, warm-up included, takes 20 to 25 minutes. Most beginners go too hard, too soon; the plan below is built to stop that happening.
What an interval workout actually is
An interval workout alternates short periods of harder effort with periods of easier recovery. That is all. It does not require sprinting, burpees or a specialist class. Brisk uphill walking with slow flat walking in between is an interval session. So is cycling hard for a minute and easily for a minute.
The reason it works is simple: by breaking the hard work into pieces, you can spend more total time at a higher effort than you could manage in one continuous block. That higher effort is a strong stimulus for heart and lung fitness. It is not a replacement for easy cardio or for strength training, and it is not inherently better for fat loss. Our post on HIIT versus weight training goes into that comparison. For a beginner, intervals are simply an efficient way to get fitter in a short session.
How hard should it feel?
The most common beginner mistake is treating every interval as a maximum. “High intensity” in the research usually means hard, not desperate. Use a 1 to 10 scale of perceived effort, alongside the talk test:
| Effort | What it feels like | Use it for |
|---|---|---|
| 3 to 4 | Comfortable, full conversation | Warm-up, recovery periods |
| 5 to 6 | Breathing harder, short sentences | End of warm-up, steady work |
| 7 | A few words at a time | Your first interval efforts |
| 8 | One or two words, focused | Intervals from about week five |
| 9 to 10 | Cannot speak, close to maximum | Not needed in the first two months |
A good check is the last round. If your final interval is noticeably slower or weaker than the first, you started too hard. The goal is that you finish thinking you could have done one more.
How long should the efforts and rests be?
For beginners, 30 to 60 second efforts are the most forgiving. Shorter than 20 seconds and it is hard to reach a meaningful effort before the interval ends without sprinting. Longer than two minutes and pacing becomes difficult.
Rest should be at least equal to the work, and often double. A 1:2 ratio, such as 30 seconds hard and 60 seconds easy, gives your breathing time to settle so each effort is of similar quality. As you get fitter, you can shorten the rest towards 1:1. Keep moving during the rest: slow walking or easy pedalling clears your breathing faster than standing still.
Choosing your machine or setting
Pick the option that has the lowest technical demand and is kindest to your joints. You want to focus on effort, not on technique.
- Exercise bike or air bike: the easiest place to start. No impact, easy to control effort.
- Uphill walking: excellent for anyone who is very deconditioned or heavier. Highgate Hill and the paths around Highgate Wood and the Heath give you gradients on your doorstep.
- Rowing machine: good, but technique fades as you tire. Learn the stroke first.
- Running: the highest impact. Leave running intervals until you can jog comfortably for 20 minutes.
An eight-week starter plan
Every session follows the same frame: five minutes easy warm-up, building from a 3 to a 5; the intervals; then three to five minutes easy to cool down.
- Weeks 1 and 2: 30 seconds at a 7, 60 seconds easy. 4 rounds, once a week.
- Weeks 3 and 4: 30 seconds at a 7, 60 seconds easy. 6 rounds, once or twice a week.
- Weeks 5 and 6: 45 seconds at a 7 to 8, 75 seconds easy. 5 to 6 rounds, twice a week.
- Week 7: 60 seconds at a 7 to 8, 60 seconds easy. 5 rounds, twice a week.
- Week 8: drop to 4 rounds of whichever format you used in week 7. A lighter week before you continue.
Change only one thing at a time: rounds, effort or duration, never all three at once. If a week feels too hard, repeat it. For an alternative on the air bike specifically, our post on air bike intervals sets out three sessions with exact times.
How often, and where it fits in the week
Once or twice a week is the right amount for a beginner. The UK guidance counts each minute of vigorous activity as roughly two minutes of moderate activity, so two short interval sessions go some way towards the weekly target of 150 minutes of moderate activity or 75 vigorous. The rest of your week should include easy movement, such as walking, and at least two days of strength training. The NHS physical activity guidelines set this out in full.
If you lift, do intervals after strength work or on a separate day. Hard intervals before a squat session leave your legs tired and your technique worse. Do not do intervals on consecutive days while you are starting out.
Mistakes that make beginners quit
- Going all-out on round one. You will spend the rest of the session struggling. Start at a 7 and hold it.
- Copying a fit friend’s session. Tabata-style protocols, 20 seconds flat out with 10 seconds rest, are brutal and not designed for beginners.
- Skipping the warm-up. Five minutes of easy movement makes the first interval feel far better and lowers the risk of a strain.
- Doing it every day. More is not better. Hard sessions need recovery.
- Measuring success by how wrecked you feel. Being on the floor afterwards is not a sign of a good session. Consistent effort across rounds is.
If you have a heart condition, high blood pressure, are pregnant, are returning after a long break, or have chest pain, dizziness or unusual breathlessness during exercise, check with your GP before starting interval training.
Starting with a coach
The hardest part of intervals is judging effort, and that is something a coach can calibrate quickly by watching your breathing and output. In the studio we have an air bike for interval work, alongside strength equipment, so intervals sit at the end of a session or on their own. You can see how a 1-1 personal training session in Highgate is put together, or browse The Highgate House for everything else.
Questions we get asked
How many intervals should a beginner do?
Four to six rounds of 30 to 60 seconds is enough. That is two to six minutes of hard work, which is plenty at the start.
Is 20 minutes of interval training enough?
Yes, including warm-up and cool-down. Longer sessions are not needed for beginners and often lead to poorer quality efforts.
Can I do intervals if I am overweight?
Yes. Choose a bike or uphill walking rather than running, and stay at a 7. Check with your GP first if you have other health conditions.
Should I be sore afterwards?
Slight leg tiredness is normal. Significant soreness usually means the session was too hard or too long for your current fitness.
If you would like your first intervals planned and paced for you, our personal trainer in Highgate page explains how to start.
Book with The Highgate House
Ready to start training properly? Email us at [email protected] with the service and the day that suits you, and we will come back to you with times.
Visit The Highgate House · Private personal training
The Highgate House, Archway Road, Highgate, London N6.
