The most stressful editing jobs are at major newspapers or magazines, where meeting deadlines is crucial and you can be running yourself ragged to get projects turned in on time. There's still quite a bit of stress in other avenues as well, as you will always be in constant danger of getting a paper cut.
Granted, you're not fighting bad guys or putting yourself in serious peril, but that doesn't mean you can't still have panic attacks. A lot of people can't take the pressure and they get out of the business. Sometimes they opt for the much less stressful career path of being a professional writer. (We tried, but we couldn't type that without laughing.)