You are not permitted to download, save or email this image. Visit image gallery to purchase the image.
Those keen to get fit will get more bang for their buck by doing short, intense spurts of exercise rather than going for a traditional jog or bike ride, a sports scientist says.
Nick Draper of the University of Canterbury said high-intensity interval training could provide a time-saving alternative to traditional endurance exercise, and actually has more health benefits.
Athletes have known the benefits of interval training - short repetitions of high-intensity exercise separated by breaks or low intensity exercise - for years, but Dr Draper and his team tested whether it could be equally applied to obese, previously sedentary people.
"In terms of overall fitness the high-intensity groups worked as well as traditional training but there were great time savings," he said.
"The high-intensity groups also had a better improvements in blood pressure, and their ability to work below maximum was also improved. Say you were running at an exercise intensity of 120 beats per minute, the endurance training group might have dropped by about 5 beats per minute whereas the high-intensity group dropped by about 10 beats."
Dr Draper said a lack of time was the most common reason gave for people not exercising, and he hoped the research would encourage people to get active - even if for shorter periods of time.
"Traditional so-called 'fat-burning' exercise involves someone walking, running or cycling continuously for 20 to 40 minutes during each session. Whereas studies of high intensity interval training as a time-saving alternative have meant that those taking part in this type of exercise have only needed to exercise for less than half this time.
"It does provide a time-saving alternative and you can get more bang for your buck in terms of that effect on your body, particularly your cardiovascular system and blood pressure."
He said people also needed to consider potential risks before embarking on a high-intensity workout regime.