Spending extra hours working out in the gym can be a waste of time according to new research.
People may be able to exercise less with the same results
A University of Glamorgan study found the amount of time spent at the gym could be cut by up to two thirds with the same level of fitness achieved.
The study involving male weightlifters found it was unproductive to spend large amounts of time training.
The researchers said the results were good news for those who have little time to exercise.
People still battling to the gym every night to stick to New Year resolutions could be wasting their time according to report author Dr Julien Steven Baker.
The findings may apply to other forms of exercise
He said: "This study indicates that it is counter-productive to spend hours at the gym and that a shorter work-out can achieve exactly the same results."
The university's Health and Exercise Science Unit looked at male recreational weight lifters over eight weeks with some doing three times as much exercise as others.
While both training groups improved their muscular strength and decreased body fat, there was no difference found between the men in each group, meaning the same results could be achieved in a third of the time.
The researchers said the findings could apply to forms of exercise other than weightlifting.
Dr Baker added: "It's quality over quantity. It means that it may be you can spend less time in the gym as long as the exercise you are doing is intense.
"Many fitness classes are now shorter in duration and promise results in quicker times and there is much research in the field to suggest that... shorter high intensity work outs can achieve maximum results in shorter periods.
"This kind of research may see a change in the way we exercise and that it may be better to do a number of regular express workouts, which would fit in with the busy lives that many people lead.
"Anyone starting up should make sure they have a good exercise programme drawn up rather than just spending lots of time in the gym.
"To someone starting to exercise, I would recommend they spend less time in the gym and when they are there to concentrate on technique."