The laddish culture promoted by men’s magazines has spawned a new medical condition: athletica nervosa, or an obsession with exercise.

New research shows that the magazines, whose titillating displays of female flesh were meant to liberate their readers from political correctness, may be trapping them into an unhealthy obsession with their own bodies.

Some readers become so anxious about their own physique that they embark on excessive exercise, spending hours running, swimming or in the gym. Athletica nervosa is already known to affect young women, but this is thought to be the first British study to link the phenomenon to men.

David Giles, a psychologist at Winchester University, who co-wrote the research, said: “We found that the more such magazines a man reads the more likely he is to be anxious about his physique.” In the study, Giles and co-author Jessica Close carried out interviews and surveys of 161 men aged 18-36 to find out how many lads’ mags they read and for how long. They also scored them for dietary habits, exercise regimes and attitudes towards appearance.

“Men who read the most lads’ mags seemed to internalise the appearance ideals portrayed by them,” said Giles. “Models in these magazines are impossibly good-looking and seeing them can make readers anxious about their own bodies.”

Recent features in lads’ mags played on men’s anxieties, with one claiming that the right gym kit adds to a man’s sex appeal, and another claiming that superb physical fitness is the only way to snare a good-looking girlfriend.

David Clarke, 33, runs his own PR agency in Borough, central London, and goes to the gym five times a week. He said: “When I started working out, looking at other people did have an effect on me although it was more to do with fashion and style magazines like GQ, Arena and Esquire rather than Men’s Health.”

A separate study at the University of Illinois two years ago showed that the influence of computer gaming magazines drove boys as young as eight to try to build their muscles.

The researchers, Kristen Harrison and Bradley Bond, said: “Exposure to video gaming magazines predicted a significant increase in [a] drive for muscularity. Research on these genres shows that the desire for a more muscular physique among adolescent males is predicted by increased exposure to health and fitness magazines.”

Single men are most likely to be influenced. Giles said: “All men who read these magazines were affected, but non-dating men much more so than those in stable romantic relationships. It could be that they become less anxious or it could be they just have less time to go to the gym when they have a partner.”

Clarke confirmed this, saying: “I’m single and a lot of friends of mine who are single work out more than those who are in a relationship.

“People get their ideas of what they should look like from the media and the amount of imagery of men and women just keeps growing,” said Giles. “None of us is immune.”

A recent study by researchers at the University of Florida showed that young men’s beliefs about the perfect body shape had changed over the past two decades, moving towards a much more muscular ideal.

Magdala Peixoto Labre, who conducted the study, said: “Adolescent males are increasingly experiencing body dissatisfaction, engaging in disordered eating and using anabolic steroids and untested dietary supplements to control their weight and to gain muscle. These behaviours can have serious, long-term health consequences.”

The emergence of athletica nervosa comes despite a slump in some parts of the lads’ mags sector. Loaded – the publishing success story of the late 1990s – lost nearly 30% of its circulation in the second half of 2007 as circulation dropped by 47,000 year on year.

FHM shed 56,114 sales and Maxim lost 53,034 sales. However, sales of Men’s Health are stable.

Thin issues

Women's magazines have long been blamed for encouraging teenagers to smoke and diet by glamorising an unhealthy “size zero” body shape.

Research last year by the Schools Health Education Unit found that 40% of 14 and 15-year-old girls skipped breakfast. Many missed out lunch as well.

The charity Beat has blamed the media and fashion industry for making girls worry about their own body image by the age of seven. It says that magazine editors doctor photographs of celebrities to make them look thinner.