Effects of physical exercise on low back pain and cortisol levels: a systematic review with meta-analysis of randomized controlled trials.

To verify the effects of physical exercise on low back pain (LBP) and serum cortisol levels in individuals with chronic LBP. Randomized controlled trials evaluating the effects of exercise on LBP perception and cortisol levels in adults with nonspecific chronic LBP were included. Four randomized controlled trials were included, with a total of 85 participants in the exercise group and 84 in the control group. The interventions reduced -1.61 (95% CI: -2.36 to -0.85) with inconsistency I = 72% (p = 0.031) the LBP level and increased 1.05 (95% CI: 0.22-2.32) with inconsistency I = 86% (p < 0.0001) the cortisol levels. The practice of physical exercise for 6 weeks or more reduced LBP levels, whereas the rate of progression of an exercise-training program in people with chronic LBP is greater than 4 weeks, but increased the cortisol serum levels in individuals with LBP.