91Èȱ¬

Experts are constantly telling us that if we’re not getting enough regular exercise we’re depriving ourselves of possibly the most powerful medicine of all, and the government recommended guidelines are 150 minutes of moderate intensity exercise a week. But is this really the best way for all of us to get the benefits?

Only about 1 in 5 of us actually achieves the government’s 150 minutes guidelines – mostly because of lack of time (although ). Over the last few years there has been a shift towards short but intense workouts, a training concept known as high-intensity interval training or HIIT. One of the most appealing things about HIIT is that sessions can be completed in as little as 15 minutes per week.

The promise is tempting: maximum impact in minimum time – with claims that HIIT can make you much fitter than exercises that take twice as long, being better at reducing body fat, increasing strength and improving insulin sensitivity – which reduces our risk of getting type 2 diabetes.

There are studies to back these claims up – but they are based on tests undertaken in lab conditions on special exercise bikes – and usually either on rather fit students or those with pre-existing health problems.

So, we wanted to find out firstly whether HIIT was as good as has been claimed for ALL of us, but then to find out whether there were more practical alternative ways to get its benefits for those of us with only a few minutes spare at home, or even those who couldn’t undertake such intense physical activity.

Dr Beth Phillips and Dr James Blackwell from the University of Nottingham have been researching the benefits of HIIT, and with their help we took a group of 24 volunteers aged between 40 and 60 years old who all have jobs and lifestyles that they describe as pretty sedentary.

We then broke them in to four groups – each trying a different form of exercise.

The first group undertook to do the recommended government guidelines of 30 minutes of moderate exercise, five times a week.

This involved things like cycling and jogging - enough to make you start to break sweat, but during which you would still be able to comfortably hold a conversation with someone.

Our second group were assigned the standard HIIT on a special resistance bike, which needs to be done in a lab or gym.

They did 3 supervised cycling sessions each week, with 5 bouts of hard cycling lasting for 60 seconds with a 90 second rest in between each one.

Beth helped to devise a series of home exercises for our contributors that would simulate the high intensity of HIIT without needing a resistance bike.

This group did high intensity exercises of running on the spot, ‘mountain climbers’ and star jumps.

Just like Group 2, our 91Èȱ¬ HIIT volunteers did 5 bouts of hard exercise (60 sec each) interspersed with 90 sec rest periods, 3 times each week.

Our fourth and final group tried a relatively new exercise, which might suit people who are less physically able to do high intensity exercises. It’s called Grip Strength Dynamometry, which is a hand grip task.

Just like the HIIT groups, this was a short, interval training task. They had to squeeze a handgrip dynamometer (an instrument that measures your grip strength) for 2 minutes at 30% of their maximum strength, with 2 minutes rest in between each squeeze. They did this 4 times in a row, 3 times each week.

(Squeezing a stress ball, or even just some rolled-up socks, is a cheap and easy alternative.)

All our volunteers were weighed, had their fitness assessed using a standard test called the VO2 max test, and their blood pressure taken before and after the 4 week experiment.