In the new issue of Radio Times magazine, Fast Diet guru Michael Mosley introduces us to his new book, Fast Exercise – a practical and enjoyable way to get the maximum health benefits from a work-out in the minimum time...


I don’t like exercise. I share the views of astronaut Neil Armstrong, who once said, “I believe that every human has a finite amount of heartbeats. I don’t intend to waste any of mine running around doing exercises.” Or the actor Peter O’Toole, who claimed, “The only exercise I take is walking behind the coffins of friends who took exercise.”

All right, that is an exaggeration. Now aged 56, I see the need and I appreciate the value of being active. I also embrace the idea that we are born to move. When I was at medical school I played quite a lot of sport, went for runs and swam. Then I started working and could no longer find the time.

Don’t get me wrong; I am not a complete slob. I love skiing, enjoy walks, relish swimming in the sea and like being active. I don’t actually think of any of these as “exercise” – something you do because you think you should.

Exercise for me means going for long run even when it is wet and cold, or trudging away on the treadmill; it is hours getting sweaty on an exercise bike or lifting heavy weights, followed by those incredulous moments when you step on the scales and discover that you have hardly shifted a pound. For me, exercise is there to be endured, not done because you want to.

More like this

If I am going to exercise I want it to be short, sharp, easy to do and soon over. This, along with the science, is what first attracted me to high-intensity training, or HIT.

One of the pioneers of this radically different approach to exercise is Jamie Timmons, Professor of Systems Biology at Loughborough University, which has one of the leading sports research departments in the UK.

When we met, Jamie made what I thought was an outrageous claim. He said that I could get many of the more important benefits of exercise from just three minutes of intense exercise a week. He was confident that in just four weeks I would see significant changes in my biochemistry. It seemed wildly unlikely, but also immensely intriguing. So I got myself tested and then I went for it. The results were a revelation.

Since my initial conversation with Jamie back in 2011, research on HIT has exploded, providing mounting evidence to support his claim.

These findings for the basis of what, in my new book, I’ve called Fast Exercise, a practical and enjoyable way to get the maximum benefits in the minimum time. But be sensible: if you are unfit, you should ease yourself into HIT. Anyone who has any doubts about their health should have a medical check-up before starting any form of exercise.

You don’t need to load up first

There is a widespread belief that carbs are needed to fuel exercise. Unless you are exercising heavily for more than an hour at a time, you have plenty of carbs on board. Eating lots of pasta will simply make you fat.

Similarly, you don’t need to load up on carbs after doing Fast exercise. You may feel a bit wobbly, but the whole point is to deplete your glycogen stores; the last thing you want to do is immediately replenish them. The average person doing a HIT session three times a week does not require special “refuelling”.

As for liquids, doing Fast exercise is not going to make you sweat, so you are unlikely to need to drink during a session.

What exercise can do for you

Improve your aerobic fitness and endurance

That’s a measure of how strong your heart and lungs are. People with good levels of aerobic fitness are much less likely to get heart disease, cancer, diabetes or become demented.

Reduce your body fat

When you push the intensity of a workout, you build more metabolically active muscle. Because muscle is efficient at burning fat, your total calorie expenditure soars.

Cut your risk of becoming diabetic

After four weeks of sprinting on the exercise bike for one minute a day, three days a week, my insulin sensitivity improved by a remarkable 25 per cent, suggesting that I had, for the time being, reduced the risk that I would become a fully fledged diabetic.

Boost your brain!

A study at the University of Illinois of 59 healthy but sedentary volunteers, aged 60 to 79, showed significant increases in the brain volume of those doing fitness training, but not of those who just did stretching and toning.

One reason why this happens may be because exercise leads to the release of all sorts of proteins in the brain, including brain-derived neurotrophic factor (BDNF). This helps protect existing brain cells and encourages the development of new ones. So you get a bigger brain, but also one that is probably better protected against dementia.

In another intriguing study, researchers at the Cooper Institute in Dallas followed 20,000 men and women who had had their baseline fitness measured between 1971 and 2009. During that time, 1,659 of them developed dementia. Scarily, the ones who were the least fit were almost twice as likely to succumb to dementia as those who were most fit.

Curb your appetite

High-intensity training also seems to suppress appetite in ways that low-intensity exercise does not. A trial in the International Journal of Obesity showed that the young men who took part ate fewer calories after high intensity (621 cals) and very high intensity (594 cals) workouts than they did after moderate exercise (710 cals).

Reduce the risk of a stroke

One of the main fears about doing HIT is that it could trigger a heart attack or stroke. In fact, there is convincing evidence that it will reduce the risks, and also help you recover faster after a heart attack. A review paper from February 2013, “High-intensity aerobic interval exercise in chronic heart failure”, came to the conclusion: “High-intensity interval training is more effective than moderate-intensity continuous exercise for improving exercise capacity in patients with heart failure.”


Michael warms up in just one minute for his cycle sessions; sometimes less (writes Peta Bee). I prefer five to ten minutes for running workouts. A warm-up should literally heat the body to increase blood flow, and loosen the muscles to ensure they are ready for activity. Warm muscles pull oxygen from the bloodstream more easily and trigger the chemical reactions needed to produce energy more efficiently. None of the workouts outlined on these pages should be started without any preparation; how much is largely up to you.


After intense exercise, it is best not to stop moving entirely. When you work out really hard, the heart has to pump much faster and blood vessels expand, leading to greater blood flow to the legs and feet. If you stop too suddenly, blood can start to pool in the lower limbs, causing dizziness.

Michael gets his HIT mainly from cycling and he spends about a minute doing gentle cycling after a fierce burst to allow his blood pressure and heart rate to return to normal. I like to spend at least five minutes after a Fast workout doing the same activity at a slower pace.

Fast Fitness: How to get your HIT


Indoor cycling is good because a modern indoor bike lets you add resistance, changing the intensity of the ride. It also enables you to continue exercising when it’s cold, wet and dark outside and is less prone to cause injuries. However, many people prefer the fresh air and unpredictable terrain they encounter outside. On a road bike, the exercise intensity can be altered by switching to a higher gear and by cycling hard uphill. Indoor bikes should be set at a minimum of 90 rpm, gradually working towards 110 rpm as you get fitter and stronger.


To make a normal run into HIT you will have to inject intensity into your workout, which means throwing in a few sprints, preferably up a hill. A hill should be challenging, but not so steep that you can’t run up it fast. If you are not especially fit, build up to this gradually. Running well uphill requires rhythm: shorten your stride slightly and aim to keep your leg turnover constant. Don’t lean forwards from the waist or back – your head, shoulders and back should form a straight line over your feet.

Stair running

The American Lung Foundation says that stair-running provides the same benefits as conventional running in half the time, because you are constantly working against gravity. Don’t hunch your back or twist your head, and bend your arms at right angles to provide power as they pump. Make sure that your whole foot lands on each step, to avoid straining the Achilles tendon, and walk (don’t run) back downstairs during recovery periods.


It is the natural resistance of water that makes swimming physically challenging, and the faster you try to swim, the harder you are going to have to work. Swimming uses a lot of muscles, but it is important to occasionally vary the strokes. Rather than judging things by time, it may be easier to judge by distance. A 25-metre length at full pelt is comparable to sprinting for around 30 to 40 seconds.


It’s quite hard to involve lots of muscle groups and achieve the necessary intensity with skipping. Your best bet is a lightweight, flexible plastic or leather gymnastic “speed” rope. Knees and ankles should be flexed, but your torso kept straight. Arms should be at your side with the rope turning from the wrists and forearms.

Running on a treadmill

There are two kinds of runner: those who like treadmills and those who don’t. Personally, I can’t see the appeal of the hamster-wheel confinement of a mechanical running belt, but many people find the treadmill reassuringly familiar. Nothing ever changes – no wind, no rain, no traffic – so they know exactly what to expect.

When it comes to performing HIT on a treadmill, the downside is having to deal with the mechanics. Switching speeds between the desired intensity for HIT and recovery can be tricky and is almost never instant. Studies have also shown that indoor running burns about 5% fewer calories than running outdoors, partly because of the lack of wind resistance and partly because the treadmill’s motorised belt propels you slightly. For these reasons, it’s advisable to crank up the gradient in order to make sure you are working hard enough. Research at the University of Brighton suggests treadmill users who want to achieve the same intensity as running on flat terrain outdoors need to set the machine at a permanent 1% incline.


With a cross-trainer you can work lots of different muscles in a short period of time. Set it on the highest incline and resistance. Gently move your arms and legs for 1 minute to loosen up. Then pick up the tempo, aiming to give a maximum effort (high tempo) for about 30 seconds, before slowing down.

Seven minutes to a stronger you

For muscle tone and flexibility, we also suggest adding these Fast strength exercises. Start by doing one seven-minute session twice a week; as you get fitter, you may want to fit in another session. The idea is to exercise as many major muscle groups as possible, and to alternate between activities in such a way as to give the ones not being worked a bit of a rest. So, if you are doing push-ups (working the upper body), you should follow these with an activity that works the core (say, abdominal crunches) or the legs (squats).

To maximise metabolic impact in as little time as possible, you should do as many repeats of each exercise as you can manage in 30 seconds and take just 10 seconds’ rest between each.

Jumping Jacks

Stand with hands by sides. Jump up, spreading legs apart as you raise your arms. you should land with your arms over your head and your feet more than hip-width apart. Jump up again, bringing legs together and arms back to your sides.


Lie face down, palms beneath your shoulders, balls of your feet touching the ground. Keep your body straight and raise yourself up using your arms. Lower your torso until your elbows form a 90-degree angle, then push up again.

Wall sit

Start with your back against a wall, feet shoulder-width apart about two feet from the wall. Slowly slide down the wall until your thighs are parallel with the ground. Don’t arch your back. Hold this position, if you can, for 30 seconds.

Abdominal crunches

Lie on your back, knees bent, feet flat, hands by your sides. Curl up your upper body without lifting your lower back off the floor, chin tucked into chest, then curl back down.


Use a bench or sturdy chair. Place one foot on the “step”. Push your body weight up, driving up through your heel and breathing out, until you are standing on the step with both feet. Step back and down to the floor, one leg at a time. Repeat with the opposite leg leading.

Tricep dips

Stand with your back to a bench or chair. Place your palms on the seat behind you and bend your knees at right angles, hips straight. Bend elbows to 90 degrees to lower your body. Push yourself back up using only your arms.


Stand with feet shoulder-width apart, hands placed lightly on opposite shoulders or in front of you. Bend from the hips, keeping the weight in your heels and back straight. Keep bending until your legs are at 90 degrees — as if preparing to sit in a chair. Push back up without bending your back.


Lie on the floor, then raise yourself onto your forearms and toes so that your body forms a straight line from head to toe. Squeeze your buttocks and hold the position for as long as possible. The first time you try this you probably won’t manage 30 seconds. Try ten seconds, resting for five and holding for ten, for a total of 30 seconds.

High-knee running

Stand tall and begin jogging either on the spot or forward. Without leaning back, drive through the balls of your feet and try to bring your knees close to chest level. Keep your hands relaxed, elbows bent and shoulders down, and swing your arms back and forth to help you keep going.


Stand with your back straight and feet shoulder-width apart. Step forward with one leg, bending both knees to 90 degrees and keeping your upper body straight. Pull back to the starting position and repeat, putting the other leg forward.

Press ups with rotation

Assume the classic press-up position, but as you straighten your arms in the upward move, rotate your body so that your right arm extends overhead. Your arms and torso should form a ‘T’. Return to the starting position, lower yourself by bending your elbows, then push up and rotate till your left hand points towards the ceiling.

Plank with leg rotation

Lie face down with your elbows on the ground; elevate your body, keeping your weight distributed between your forearms and feet.Your elbows should be bent at a 90-degree angle. Keep your back straight with your hips raised off the floor. Squeeze your torso tight, slowly lifting one foot 6-8 inches off the ground and hold the position for a few seconds. Lower your leg back to the starting position.

Reverse curl

As an alternative to the plank, lie on your back, with your hands by your sides, your feet up and your thighs perpendicular to the floor. They should not go lower than this for the entire movement. Using your lower abs, roll your pelvis to raise your hips off the floor. Your legs will now be at a 45-degree angle to the floor. Hold briefly at top position. Return slowly to the start position. Repeat in a controlled way for 30 seconds.

Fast exercise can be worked into a busy life with relative ease. You can even do it in your normal clothes. Along with co-author Peta Bee, I have included two types of exercise with very different purposes: Fast Fitness and Fast Strength.

Depending on how long you want to spend warming up or cooling down, most exercises can be done in less than ten minutes a day or just incorporated into what you are already doing. Aim to split your time about 50-50 between Fast Fitness and Fast Strength and you can’t go far wrong.

A typical weekly programme for the average exerciser, therefore, might comprise two days of Fast Fitness and two days of Fast Strength. For those who are fitter, three days of Fast Fitness and two days of Fast Strength.

Fast Fitness is based on High Intensity Training (HIT), the aim being to boost your cardiovascular system and reduce your diabetes risk. Try to do three sessions as week, either as part of another exercise regime (ie add HIT to your run), as part of your commute or by itself.

With Fast Fitness, the temptation will probably be to do more. Don’t. It won’t make it more effective and the danger is, if you go crazy you’ll damage yourself.

Michael Mosley and Peta Bee offer helpful exercises inside this week’s Radio Times magazine (on sale Tuesday 21 January).


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