Exerceise ‘junkies’ have the same withdrawal symptoms as heroin addicts when they try to stop, a study has shown. Being weaned from physical activity produces the trembling, teeth chattering and drooping eyelids exhibited by drug addicts who go cold turkey, researchers said. Obsessive exercising to shed weight can lead to the potentially fatal condition anorexia athletica, they added. The report by neuroscientists from Tufts University in Boston suggests that as soft drugs can lead to hard drugs, so mild exercise such as jogging or bike riding can turn into triathlons and 100-mile bike rides. Health News