5 Effective HIIT Workouts for Busy Schedules

What is HIIT?

Harvard Health describes high-intensity interval training as vigorous activity done in short intervals, with brief periods of rest or lower-intensity activity between them.

The idea is simple. You push hard for a short time, recover, and repeat. Because the hard efforts are intense, the whole session can be short.

The main formats

• Traditional HIIT: 30 to 90 seconds of high-intensity effort, followed by an equal or longer period of lower-intensity activity or rest.
• Tabata: a specific version with 20-second work intervals and 10-second recovery intervals, according to Harvard Health.

What counts as hard is different for each person. It depends on your fitness. Choose an effort that feels hard for you, but that you can repeat with good form.

Why people like HIIT

Harvard Health says that a 20-minute HIIT session will burn more calories, strengthen your heart more and help your body use oxygen more efficiently than 20 minutes of moderate exercise.

It also says you can meet the federal exercise guidelines in 75 minutes a week with vigorous exercise, compared with 150 minutes a week of moderate activity. And it notes that high-intensity bursts may trigger the release of endorphins, the brain's feel-good chemicals.

• Short sessions fit a busy day.
• It can feel more engaging than steady exercise.
• You can do it with no equipment.
• It works for many forms of exercise, including walking, cycling and bodyweight moves.

These are general findings. HIIT is not better for everyone, and it is not a replacement for strength training or for easy daily movement.

Who should check with a doctor first

Harvard Health says that if you have heart disease or are at increased risk for it, you should check with your doctor before adding high-intensity effort to your routine.

More generally, it says to check with your doctor before starting any exercise program if you have dizzy spells, are unsteady on your feet or have a chronic or unstable health condition, such as heart disease, asthma, high blood pressure, osteoporosis or diabetes.

• Stop immediately if you feel chest pain, severe breathlessness, dizziness or sharp pain.
• If you are new to exercise, build a base with walking and strength work for several weeks first.
• If you are older, adjust intensity to your fitness level.

How to start safely

Harvard Health suggests starting with a few short intervals of high-intensity exercise, separated by longer periods of moderate or easy exercise, and gradually increasing the number and length of the intervals.

• Warm up for 5 to 10 minutes.
• Begin with 4 to 6 rounds of short, hard efforts and long recoveries.
• Aim for effort that feels hard, not all-out.
• Cool down for 5 to 10 minutes.
• Leave rest days between sessions, so your body can recover.

Choose low-impact options if your joints are sensitive, such as brisk walking uphill, cycling or fast marching.

Workout 1: Walking or jogging intervals

• Warm up: 5 minutes of easy walking.
• Hard: 30 seconds of fast walking, or a light jog.
• Recovery: 60 to 90 seconds of easy walking.
• Repeat 6 to 8 times.
• Cool down: 5 minutes of slow walking and stretching.

This is a great starter. If it feels too hard, shorten the hard effort or lengthen the recovery. See our guide to walking for fitness to build your base.

Workout 2: Bodyweight circuit

Do each move for 30 seconds of steady, controlled effort, then rest for 30 seconds.

• Squats, or sit-to-stands.
• Incline or wall push-ups.
• Marching or high knees.
• Glute bridges.
• Plank on your knees or toes.

Repeat the circuit two or three times, with 1 to 2 minutes of rest between rounds. Keep your form clean, and slow down if it slips.

Workout 3: Tabata-style session

Harvard Health describes Tabata as 20-second work intervals with 10-second recovery intervals. It is very demanding, so only try this if you are comfortable with the earlier workouts.

• Choose one simple move, such as fast marching, squats or a stationary bike.
• Work hard for 20 seconds.
• Rest for 10 seconds.
• Repeat 8 times, for 4 minutes.
• Rest for 2 to 3 minutes, and repeat with another move if you feel good.

Keep the total number of rounds small at first. It is easy to overdo it.

Workout 4: Stair or hill intervals

• Warm up: 5 minutes of easy walking.
• Hard: 30 to 45 seconds of brisk stair climbing or hill walking, holding a rail if needed.
• Recovery: walk back down slowly, or rest for 60 to 90 seconds.
• Repeat 5 to 6 times.
• Cool down: 5 minutes of slow walking and calf and thigh stretches.

Take care on stairs. Wear supportive shoes, and stop if you feel unsteady.

Workout 5: Cycling intervals

• Warm up: 5 minutes of easy pedaling.
• Hard: 30 to 60 seconds of faster pedaling or a harder gear.
• Recovery: 60 to 90 seconds of easy pedaling.
• Repeat 6 to 8 times.
• Cool down: 5 minutes of easy pedaling.

Cycling is low-impact, so it can suit people with sensitive joints. Use a stationary bike or a safe, flat route outdoors.

How to fit HIIT into your week

HIIT is demanding, so use it as one part of a mix, not the whole plan.

• 1 or 2 HIIT sessions a week to start.
• 2 strength sessions on other days. See our beginner strength training guide.
• Easy walking on most days.
• At least one rest day.

The NHS suggests at least 150 minutes of moderate activity a week or 75 minutes of vigorous activity, plus strength work on at least 2 days. HIIT can help you reach the vigorous target.

How to progress safely

Progress means making exercise a little harder as your body adapts. You only need to change one thing at a time. Harvard Health advises choosing a weight or resistance that is challenging but manageable, and says that if you are grunting or getting stuck in the middle of a lift, you are using too much weight.

• More repetitions. Add one or two per set each week, up to about 12.
• More sets. Move from one set to two, as Harvard Health suggests.
• More load. Use a heavier weight, a resistance band or a backpack with books.
• Slower tempo. Take three seconds to lower in each repetition.
• Harder versions. Move from wall push-ups to incline push-ups, then floor push-ups.
• Less rest. Shorten the breaks between moves a little.

Give each change a week or two. If a week feels too hard, go back to the earlier level. Progress is not a straight line.

Recover well between workouts

Recovery is where you get stronger. Give your body what it needs between sessions.

• Sleep at least seven hours, and keep a regular schedule.
• Eat regular meals with protein, vegetables and whole grains.
• Drink water through the day.
• Take at least 1 day of rest between workouts for the same muscle groups, as the NIDDK suggests.
• Move gently on rest days, with a walk or light stretching.

Read our guide to rest and recovery to learn how to read your body's signals.

Common myths

Myth 1: You have to feel very sore to get results

Mild tiredness is normal, but severe or lasting soreness is a sign to ease off. Progress comes from steady, repeated effort.

Myth 2: You can spot-reduce fat

Working one area does not remove fat only from that area. Fat loss happens across your body.

Myth 3: More is always better

Muscles adapt during rest. The NIDDK suggests at least 1 day of rest between workouts for the same muscle groups.

Myth 4: Short workouts do not count

NHS Better Health says even 10 minutes a day can make a difference, and the NHS says you can break weekly activity into shorter sessions.

Common HIIT mistakes

• Going all-out too soon. Build up gradually.
• Skipping the warm-up. Harvard Health says cold muscles can lead to injury.
• Doing HIIT every day. Recovery matters.
• Sloppy form. Slow down when you tire.
• Exercising through pain. Stop if something hurts.
• Doing hard sessions late at night. Vigorous exercise close to bedtime can affect sleep for some people. See our guide to sleeping better after a workout.

Recap: the main points

• HIIT alternates short hard efforts with rest or easy movement.
• Traditional HIIT uses 30 to 90 seconds of effort, and Tabata uses 20 seconds on and 10 seconds off.
• A 20-minute HIIT session can burn more calories and strengthen the heart more than moderate exercise, according to Harvard Health.
• Start with a few short intervals and longer recoveries.
• Check with your doctor if you have heart disease or risk factors.

HIIT workouts: frequently asked questions

Want a full plan? Read our Beginner Fitness Guide.

Related reading: The Top 5 Workout Routines for Toning and Strengthening

Sources and further reading

We checked the figures and guidance in this article against these sources. This article does not give personal medical advice.

• Harvard Health: Interval training, a shorter, more enjoyable workout?
• Harvard Health: Exercise 101, don't skip the warm-up or cool-down
• Harvard Health: Do you need to see a doctor before starting your exercise program?
• NHS: Physical activity guidelines for adults aged 19 to 64
• NIDDK: Health tips for adults

Want more? Head back to the Fitness hub or read the Start Here guides.