Is 30 minutes a week really all you need? (Getty)How often have you wanted to slim down, but been discouraged before you even started? All that sweaty effort and those endless hours plodding away on the elliptical machine or treadmill are, unsurprisingly, the biggest turn-off when it comes to getting into shape. But it turns out that you're actually spending more time than you need to. Yep, researchers have discovered that workout sessions lasting just10 minutes, performed three times a week, can (and will) transform your body for the better.
Based on findings about how exercise affects our bodies, scientists have reached a startling new conclusion: It's not how long you spend working out that matters, but how hard you push yourself. And if you're prepared to give an all-out effort in short bursts —an approach the experts call High Intensity Training (or HIT) — then the reward is a workout that need only last a matter of minutes, yet will produce a long list of benefits, among them weight loss and better muscle tone. This is the underlying principle of "FastExercise," a new approach to micro-workouts that really will help you to drop a dress size before you know it.
Related: 12 High-Intensity Training Tips
What HIT-style workouts offer are a super-efficient means of enhancing circulation and stripping away unwanted body fat, paving the way for a more streamlined and toned appearance. Sound too good to be true? Well, consider this: A study at the University of Ontario got 10 men and 10 women to do either HIT in the form of four-to-six bursts of 30-second sprints, or hour-long runs three times a week for six weeks. At the end of the trial, the steady runners had lost some body fat, but the HIT exercisers had shed more than twice as much, an impressive 12.4 percent of their fat mass. And they had done it in a fraction of the time.
Ideally, your three weekly sessions will include 10 minutes of running, walking, and cycling with fast "sprints" as well as a mini FastStrength circuit, with exercises such as squats and lunges designed to recruit multiple large muscle groups. This combination will elicit a significant metabolism-boosting effect that can last for up to 72 hours after each workout. There's even evidence of an increased level of compounds such as catecholamines and growth hormone in the blood both during and after HIT workouts that are known to speed up the loss of fatty tissue around the body much more effectively than traditional slow-paced jogging or lengthy weight training sessions.
Let's make no bones about it: "FastExercise" is not an easy option. It's tough and requires effort, but because the workouts are bite-sized, they're surprisingly manageable. So let's get started. What do you have to lose (other than that dress size, of course)?
Want to give it a shot? Here are two workouts to try.
The Bare Minimum
40 seconds hard exercise (2x20 seconds)
Total: 4 to 6 minutes, including recovery
Unbelievably, there is evidence that just 40 seconds of intense activity can make a difference. If you are only doing a few bursts, 20 seconds seems to be the minimum time that will make a difference.
The basic principle here is to push yourself in two brief 20-second bursts. The most obvious activity to choose is cycling; if you are doing it indoors, you will need an exercise bike with variable resistance on which you can crank up the intensity mechanically; and, if cycling outside, you will need to find a hill, preferably quite a steep one, and use gravity to increase your workload. Running or swimming will also work.
In the case of running, you will need to find some way of cranking up the resistance for your 20-second spurts — either mechanically, on a treadmill in the gym, or by using a hill if you are outside.
• Start off with a couple of minutes of gentle pedaling/running/swimming.
• When you feel ready, speed up and work your body as hard as you can for 20 seconds, before slowing down.
• Repeat the sprint after you’ve had a couple of minutes of gentle pedaling/jogging/walking to recover. Recovery time is important.
In total, the Bare Minimum should take less than 10 minutes. If you're out of shape or have never tried HIT before, it may be worth slowly building up the sprints from 2x10 seconds to 2x20 seconds. Once you have mastered 2x20 seconds, you may want to add on another 20-second sprint which, along with the recommended recovery period, will add another couple of minutes to your regime.
The 60-Second Workout
2½ minutes hard exercise
Total: 10 to 11 minutes, including an 8-minute recovery
This 60-second workout evolved out of work done by the sports science team at McMaster University when the researchers were trying to find an effective but "gentler" version of their challenging 30-second sprint.
The basic principle is simple: Alternate 60-second bursts of activity with 90-second recovery periods. For example, 1 minute on, 1 1/2 minutes off. It’s wonderfully flexible and can be done with any of the activities listed above, like cycling, running, swimming, and can be scaled down or up according to what you require.
You might think that 60 seconds of HIT has to be tougher than 30 seconds, but this version is not. The key difference is that you don’t push yourself quite as hard. Instead of going flat out, you exercise for a minute at about 90% of your best effort, aiming to push your heart rate up to around 80 percent of heart rate max by the end of the first minute.
To find your heart rate max (HR max), the safest way is by using this formula: 220 minus your age for men and 226 minus your age for women.
The less fit should definitely start with three bursts; if you really want to push your limits, you can do the full 10 (particularly beneficial if you are preparing for an endurance event). Our recommendation, if you consider yourself rather fit, is that you aim for a steady five. So:
• Two minutes of warm-up.
• 5x60-second bursts of activity, with 90 seconds’ recovery between each burst.
• One minute of cooldown.
Now get going and good luck!
Peta Bee is the co-author of "FastExercise," along with Dr. Michael Mosley, and writes regularly for The Times, Daily Mail, andSunday Times. She has degrees in sports science and nutrition and is a qualified running coach. Peta won the Medical Journalists’ Association Freelance Journalist of the Year in 2008 and 2012, and lives with her family in Berkshire, England.