Ever wondered why you struggle to get yourself to the gym? Well, the answer may lie in your genes.

Scientists now claim a desire to keep fit and do regular exercise is hereditary and passed down through the generations. The discovery means that people who suffer from laziness could be treated in the future with drugs, which target the genes that promote activity, reports express.co.uk.

This could provide a major breakthrough in the battle against obesity.

Experts have long said that dieting without increasing exercise is unlikely to result in significant weight loss.

A scientific study earlier this year confirmed this finding and experts also insisted that combining a healthy diet with regular bouts of exercise is the best way to stave off cancer, heart trouble, diabetes and even Alzheimer's disease.

Now researchers have found activity levels can be enhanced in mice by selective breeding, the process of rearing animals for particular genetic traits.

Biology professor and the lead author of the research Theodore Garland Jr said: 'Our findings have implications for human health.'

'Down the road, people could be treated for low-activity levels through drugs that target specific genes that promote activity. Such interventions could also make it less comfortable for people to sit still for long periods of time,' he said.