Long Term Effect of Different Exercise Intensities on Serum Cortisol Level in Osteoarthritis Patients

Background: Exercise intensity has a significant impact on the levels of several hormones such as cortisol, adrenalin and testeseron.

Purpose: To compare between the effect of low intensity (40-60%) and high intensity (65-80%) aerobic exercises training on serum cortisol level, knee pain, stiffness and difficulty performing ADL activities in over weight osteoarthritic patients.

Methods: Forty overweight, knee osteoarthritic patients were selected between Jan and Mar 2016 from Elmenia University Hospitals, their ages ranged from 45-50 years. Patients were assigned randomly into two equal groups. Group A received aerobic exercises intensity 45% to 60% of maximum heart rate (MHR) and Group B received aerobic exercises intensity 65% to 75% of MHR. Both groups received aerobic exercises for 30 min / 3 sessions/week for 4 weeks. Serum Cortisol level and WOMAC questionnaire were assessed before the study and after 4 weeks of training.

Results: Serum Cortisol level after training in comparison to before training significantly decreased in Group A (P-value < 0.001) and significantly increased in Group B (P-value < 0.001). Also WOMAC questionnaire pain section, stiffness section and difficulty performing daily activities (ADL) section show statistically significant decrease after 4 weeks of training in both groups (P-value < 0.001). There was no significant difference in post training serum cortisol level, pain, stiffness or difficulty performing ADL activities between all groups (P-value > 0.05).

Conclusion: High intensity exercise (65-75%) significantly increased Serum Cortisol level while low intensity exercise (45-60%) significantly decreased Serum Cortisol level. Both high and low intensity aerobic exercises are effective in improving Knee OA symptoms.