By Daisy Dumas
Buff: Jake Gyllenhaal and Heidi Montag are extreme exercisers. Gyllenhaal became addicted while training for Prince of Persia while Montag exercised for up to 14 hours a day before the MGM Grand pool party last month
We all know that exercising is a vital part of staying healthy.
But, even when it comes to fitness, anything in excess can be damaging.
A worrying new trend points to some Americans over-exercising, in what is known as ‘extreme exercising’.
High-profile addicts include Hollywood actor, Jake Gyllenhaal, and reality TV star, Heidi Montag.
Gyllenhaal, who completely transformed his body for the buff title role in Prince of Persia, admitted in March that he became addicted to exercise after working out for the blockbuster movie.
In an interview with Men’s Journal, the ‘cardio monster’ said he even suffered shin splints and has ‘had to teach [him]self to slow down a bit.’
Montag has replaced an apparent addiction to plastic surgery with a hours at the gym. Following drastic facial augmentation in 2009 - in which she underwent 10 dangerous procedures in a single day - Heidi Montag told ABC News in an interview last year that she ‘almost risked everything, all my relationships and myself, for vanity.’
Whether or not driven by the same urge, the fake-breasted celeb reportedly worked out for up to 14 hours a day before the MGM Grand's Wet Republic VIP pool party in Las Vegas last month.
Her dedication to the gym has raised alarm with experts.
Fitness expert, Michael Shaw, owner of New York Personal Training, told MailOnline, 'Like anything in the extreme, extreme exercise is a problem.'
'The most obvious danger is injury, overusing and overloading joints. The body's not meant to withstand that type of training.'
He says that the central nervous system can be affected, causing sleeplessness, while problems can also arise from 'the body not being fuelled right.'
Perhaps most worrying is his observation that extreme exercisers 'tend to have an unrealistic view of what the body is', suffering from body dismorphia.
Extreme exercise can lead to anorexia athletica, when working out becomes compulsive.
Addicted: Extreme exerciser, Brooke Mora, works out for up to 30 hours a week
Shaw recommends that his clients do not work out for more than 45 minutes to an hour at any one time.
The U.S. Department of Health and Human Services recommends just 2 and a half hours of moderate aerobic activity a week for adults, while the American College of Sports Medicine recommends doing moderately intense cardio 30 minutes a day, five days a week, or vigorously intense cardio 20 minutes a day, three days a week.
Both Gyllenhaal and Montag's work-out routines far exceed the recommendations – and it's not limited to celebrities, either.
In an interview with Good Morning America, extreme exerciser Brooke Mora described how a bad break-up lead to a fitness compulsion.
Forgetting the balanced lifestyle mantra, 'everything in moderation', the 31 year old works out for up to 30 hours a week, fitting training in before and after work and on her lunchbreak.