Abdominal exercises can be done every day if you are able to. Most people perform abdominal exercises 1-3 days a week. People with chronic low back pain can perform abdominal exercises 3-5 times a day to relax their muscles and burn off the stress that is stored in their bodies.  Abdominal exercises should not be performed every day because excessive strain on the abdominal muscles can lead to aftershocks that can cause injury, which is why abdominal exercise routines for most people should be performed 1-3 times a week.