Effects of aerobic exercise on low back pain patients in treatment

Abstract

Background context: Aerobic exercise (AE) has been prescribed to improve fitness and well-being in apparently healthy individuals and cardiac, orthopedic, and other patient populations. AE has not previously been studied as a sole treatment for low back pain patients (LBPP).

Purpose: This study evaluated the effects of low to moderate aerobic exercise as an adjunct treatment for LBPP, 30 to 60 years of age, in a neurosurgical practice during a 2.5-year follow-up to an initial 10-week exercise program. The purpose of this study was to determine the effects of short- and long-term AE on LBPP. The initial 10-week phase compared AE and nonexercising controls on mood states and pain/symptoms.

Study design/setting: A matched stratified design was used to input LBPP with similar previous clinical treatments as well as age and sex into AE or control groups.

Patient sample: After screening 68 LBPP from a New England private neurosurgical practice, 40 patients met qualification criteria, and 35 volunteered for this AE research study. The LBPP in this study were 30 to 60 years old and had the following medical diagnoses: herniated nucleus pulposus at one or more lumbar levels, degenerative discopathy, lumbosacral strain, and spinal canal and/or foraminal stenosis.

Outcome measures: The measure of mood states was the Profile of Mood States, and the measure of pain was the Brief Pain Inventory. The 2.5-year follow-up phase compared AE and nonexercise patients on the following treatment variables: medical office visits for pain/symptoms, physical therapy referrals, epidural steroid injections for pain/symptoms, prescription of pain medications, and work status.

Methods: Thirty-five LBPP were matched stratified into an AE or nonexercise control group for a 10-week exercise program. After the 10-week exercise program, all subjects were given the opportunity to cross over to the opposite group. Those patients choosing to exercise were advised to follow a low to moderate aerobic exercise prescription (walking or cycling, 60% age-predicted maximal heart rate, 4 days per week for 45 minutes per day). None of the original AE group crossed over to the nonexercise group because of symptoms relating to their previous exercise participation. All participants were contacted at 6-month intervals, and the number of medical office visits for pain/symptoms, physical therapy referrals, number of epidural steroid injections, and number of prescriptions for pain was charted for 2.5 years. Work status was evaluated by comparing the change in number of patients not working, working part time, working full time, or number changing from full time to part time or not working from randomization to the end of follow-up. Patients following the exercise prescription at least 50% of the time were compared with those exercising less than 50% of the time during the 2.5-year follow-up. Significance was determined at the .05 level using Fisher's exact test or the Kruskal-Wallis test.

Results: The initial 10-week AE phase of the study indicated that low to moderate AE significantly improved mood profile (AE X=−9.58; control X=19.11; p<.01) but did not alter pain levels. AE patients in the 2.5-year follow-up phase received significantly fewer pain medication prescriptions (AE X=2.76; control X=13.35; p<.02) and were given fewer physical therapy referrals (AE X=0.17; control X=1.64; p<.002). There was no significant difference in the number of medical office visits for pain or epidural blocks administered to either group. Work status was improved only in exercising patients (AE X=+0.24; control X=−0.35; p<.04).

Conclusions: Low to moderate aerobic exercise appears to improve mood states and work status and reduce the need for physical therapy referrals and pain medication prescriptions for LBPP in the care of a neurosurgeon.

Introduction

Low back pain (LBP) with related symptoms is a common and pervasive problem in today's society, affecting 60% to 90% of all US adults during their lifetime 1, 2. The cost of medical care and lost work time have been estimated to be in the billions of dollars annually 2, 3, 4, 5, 6.

Current nonsurgical and noninvasive treatment modalities for LBP include bed rest, medication (analgesic and/or anti-inflammatory), manipulation, patient education with emphasis on biomechanics/ergonomics, physical therapy (PT), strength training, and aerobic exercise (AE). In previous research, AE has been used in combination with other treatments 1, 3, 7, 8, 9 in the rehabilitation of LBP, but not as a sole intervention. AE may contribute to the overall treatment plan for patients with LBP because of the benefits for the general population, which include improvements in mood state 10, 11, 12, 13, strengthening the supporting low back musculature 12, 14, increasing nutrition for the disc [15], prevention of further low back injuries 16, 17, and prevention of general disease states 18, 19, 20.

AE may be important in LBP rehabilitation and maintenance of low back health, because it is a form of exercise that can minimize spinal loading while presenting low back muscles with a sufficient load to lead to a training effect 21, 22, 23, 24. Low back tissues may need mild stressing (stimulation from walking or other forms of exercise) to enhance their health, but too much loading can be detrimental 22, 23, 24. Some of the benefits of AE for patients with LBP may include enhanced oxidative capacity of skeletal muscle and improved neuromotor control and coordination 25, 26. Prevention of low back injury has been suggested by Cady et al. 16, 17, who found that firefighters who were less fit had more episodes of low back injury and incurred more cost for work-related injuries. Nutter [20] found that AE can improve strength and endurance and prevent fatigue. This effect of AE could prevent improper body mechanics resulting from fatiguing muscles and thus reduce low back pain and injury. AE offers potential psychological benefits to patients with LBP by improving mood state and overall feeling of well being 10, 13, 27, 28, 29.

Exercise studies of 6- to –20-week durations are generally associated with decreased depression and an enhanced self-esteem [13]. Martinsen [28] found patients with mild to moderate depression to benefit from aerobic exercise and weight training. In young adults, running and aerobic dance were shown to be more effective in improving mood state than weight training as measured by the Profile of Mood States (POMS) [10]. In addition, normal 40-year-old male and female adults showed improved self-concept and decreased tension (POMS) resulting from a prescribed 8-week program of walking, jogging, or cycling [29].

Because of the potential positive physical and psychological benefits of AE and benefits from reduced medical services and return to work, the purpose of this study was to evaluate the effects of AE as a sole exercise intervention for patients with LBP. This included a 10-week exercise phase to determine the effects of a low to moderate program of AE on mood profile and pain severity in patients with LBP and a 30-month follow-up comparing use of medical services and changes in work status between AE and nonexercising patients with LBP.