Aim: To verify the effects of physical exercise on low back pain (LBP) and serum cortisol levels in individuals with chronic LBP. Materials & methods: Randomized controlled trials evaluating the effects of exercise on LBP perception and cortisol levels in adults with nonspecific chronic LBP were included. Results: 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 I2 = 72% (p = 0.031) the LBP level and increased 1.05 (95% CI: 0.22-2.32) with inconsistency I2 = 86% (p < 0.0001) the cortisol levels. Conclusion: 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.