A recent study linking e-mail to stress comes as no surprise to Temple psychology professor Don Hantula. The study put 13 workers on heart monitors as they went through their daily grind, with and without e-mail. It found a cardiac marker of stress during the e-mail period. "The sort of results we see, of heightened vigilance being associated with other markers of stress, is something that has been part of our history forever," Hantula said.