Physical activity should be an integral part of weight loss therapy and weight maintenance. Initially, moderate levels of physical activity for 30 to 45 minutes, 3 to 5 days a week, should be encouraged. Physicians and other health care professionals are encouraged to consult other sources and confirm the information contained within this site. Consumers should never disregard medical advice or delay in seeking it because of something they may have read on this website. Physical activity causes the discs to swell with water and then squeeze it out, which exchanges nutrients between the discs and other spinal structures. When the patient does not engage in enough physical activity, the spinal discs are deprived of the nutrients they need to stay healthy and functional.