If you get through the training, you've known stress. Your early career will test your knowledge and you'll be asked to do your work in record time. The average work week for a resident is 51 hours, which isn't too bad until you realize that the maximum number of hours you can be put on the job is 18. You'll have to identify and sometimes treat diseases with the latest, sometimes risky technology. You really need to be right. Misdiagnosing a patient not only hurts the patient, it costs the healthcare industry billions of dollars in repeat testing. So if you can perform at a superhuman level and at superhuman speed without freaking out, the stress is no big deal.