IT is good news for time-poor men who struggle to make it out of the office and into the gym - less than an hour of exercise a week is enough to increase muscle and potentially reduce the risk of type 2 diabetes.
A British study has found that just three weekly weight-lifting sessions of 15 minutes each are required.
Men who did exercises including bicep curls and bench presses for this long saw results within a fortnight.
Over six weeks, 10 overweight men increased their thigh muscles by 10%, lost almost 2kg of body fat and had healthier blood sugar levels.
Researchers say the key is for men to exercise as hard as they can.
Dr Stuart Gray, lecturer in exercise and metabolic health at Glasgow University, said: “This may have important public health implications as the time commitment of exercise can be reduced and it is well established that time is a major barrier to exercise participation.”
Previous research has shown that 45-minute exercise sessions can boost muscle and reduce insulin resistance - the inability to manage blood sugar which can lead to type 2 diabetes. But the latest research shows this can be done far more quickly when people exercise at their limit.
Men were asked to lift the heaviest weight they could cope with, which they could manage only once.
Researchers then asked them to lift around 80% of that weight across nine different exercises, including bench presses, bicep curls and leg lifts.
Each 15-minute session was made up of these nine exercises, during which muscles and strength were measured.
Their blood was also tested for glucose levels at half-hour intervals after drinking a cup of sugar water.
The results show that their muscles grew bigger and stronger after just a fortnight.