The Effect of Chiropractic Spinal Manipulative Therapy on Salivary Cortisol Levels

OBJECTIVE This study examines the effect of chiropractic spinal manipulative therapy on salivary cortisol levels. DESIGN Prospective case series over six weeks duration. The trial consisted of establishment of each individual's baseline cortisol level, a two week treatment period (4 treatments), and a two week post treatment period. SETTING Macquarie University Chiropractic Research Centre. PARTICIPANTS Nine subjects (six male, three female), employed in a large corporation, volunteered to the trial of spinal manipulative therapy. MAIN OUTCOME MEASURES Saliva samples were analysed using an Amerlex Radioimmunoassay Kit to determine the cortisol concentrations present. RESULTS Statistical interpretation, after exclusion of an apparent outlying subject, revealed results of statistical significance (p<0.001) for reduction of salivary cortisol over the complete five week study. In addition, there was no apparent alteration in salivary cortisol levels immediately preceding and 15 minutes after spinal manipulative therapy. CONCLUSION The initial evidence is inconclusive, however, the potential relationship demands further investigation. Additional research is necessary in measuring the physiological effects of Chiropractic spinal manipulative therapy. This method is currently being used in a larger randomised controlled trial.