Arthur D. Sculco, MS, Norwich, CT, USA; Donald C. Paup, PhD, Larry F. Hamm, PhD, Washington, DC; Bo Fernhall, PhD, Syracuse, NY, USA; Mario J. Sculco, MD, Norwich, CT, USABackground: There is a paucity of data concerning the effects of aerobic exercise as a treatment for patients with chronic low back pain. Aerobic exercise (AE) is an accepted treatment modality in selected clinical patient populations but has not been previously studied as a sole treatment for patients with symptomatic lumbar herniated nucleus pulposus (HNP).Purpose: The purpose of this study was to assess the effects of moderate intensity AE as the sole exercise intervention in patients with symptomatic lumbar HNP. Clinical outcome measures included assessment of low back pain/symptoms and low back flexibility and function. In addition, changes in body mass index (BMI) and selected cardiovascular fitness variables were analyzed.Study design: This study was a randomized prospective trial involving 75 patients with symptomatic lumbar HNP.Patient sample: After screening 87 symptomatic patients with lumbar HNP being treated in a private neurosurgical practice, 79 patients met study inclusionary criteria, and 75 volunteered for this prospective AE research study.Outcome measures: Clinical outcome measures included the sit-and-reach (SR), functional reach (FR) and trunk forward flexion (TFF) tests and the following five visual analog scales: low back pain/symptoms (LBPS), pain/symptoms above knee (AK), pain/symptoms below knee (BK), activities of daily living (ADL) and occupational work capacity (OWC). Physiologic outcomes included BMI, resting heart rate (HR) and blood pressure (BP), oxygen pulse and pulse recovery test.Methods: A total of 75 patients with symptomatic lumbar HNP were randomized into an AE and a control group (C) group. All were assessed at baseline after randomization and again after 12 weeks of AE training. The AE prescription was walking or cycling at 70% of age-predicted maximal heart rate, 4 days per week, for 45 minutes per session. All patients exercised unsupervised at home. The C group patients continued receiving usual care, as did the AE patients. In addition to descriptive statistics, group mean differences were analyzed using t tests. Statistical significance was set at the .05 level.Results: AE training resulted in significant improvements in HR, oxygen pulse and the pulse recovery test. The only functional test result reaching significance was SR. Three of the five visual analog scores assessing symptoms or function improved significantly: LBPS, ADL and BK. Improvement in the remaining two visual analog scales approached significance (OWC, p=.076; AK, p=.056). Patients reported no untoward effects of the AE program.Conclusions: Moderate-intensity AE training in patients with symptomatic lumbar HNP is safe and associated with improvements in physiological variables, functional scores and symptomatic pain.